UNITED STATES ENVIRONMENTAL
PROTECTION AGENCY
Report to Congress
4TH & M STREET SOUTH WEST
WASHINGTON, D.C.. 20460
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PREFACE
The Clean Air Act, as amended in 1970, initiated a coordinated
national effort toward reducing air pollution through research,
regulations, enforcement, and related programs.
Section 202(b)(4) of the Clean Air Act requires the EPA
Administrator to report yearly on measures taken in relation to motor
vehicle emission control. Section 202(b)(4) reads as follows:
"On July 1, 1971, and of each year thereafter, the
Administrator shall report to the Congress with respect
to the development of systems necessary to implement
the emission standards established pursuant to this
section. Such reports shall include information regarding
the continuing effects of such air pollutants subject
to standards under this section on the public health
and welfare, the extent and progress of efforts being
made to develop the necessary systems, the costs
associated with development and application of such
systems, and following such hearings as he may deem
advisable, any recommendations for additional
Congressional action necessary to achieve the purposes
of this Act. In gathering information for the purposes
of this paragraph and in connection with any hearing,
the provisions of Section 307(a) (relating to subpoenas)
shall apply. "
This report covers the period July 1, 1974 through June 30, 1975.
It has not been updated to reflect changes that have occurred since
June 30, 1975.
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TABLE OF CONTENTS
Page
PREFACE
LIST OF FIGURES iii
LIST OF TABLES. iv
I. INTRODUCTION AND SUMMARY. . . . . 1
II. EPA ACTIONS 5
A. Decisions on 1977 Emissions Standards 5
B. Waiver of Federal Preemption for 1977 Motor
Vehicle Emissions Standards for California. 6
C. Motor Vehicle Regulations 7
1. Light Duty Diesel Trucks 7
2. Light Duty Diesel Trucks in High Altitudes 7
3. 1977 Model Passenger Vehicles in High Altitudes 8
4. Exhaust Emission Standards for Hydrocarbons 8
5. Certification of Low-Emission Vehicle 8
6. Importation of Catalyst-Equipped Vehicles 9
7. Recall 10
8. Reporting of Defects. 10
D. Selective Enforcement Auditing 10
E. Certification and Surveillance Procedures 11
1. Certification Testing. 11
2. Inspections/Investigation Program. 12
3. Surveillance Testing. 12
F. Other EPA Programs 14
1. Antitampering Program. 14
2. Recall Program. 15
3. Imports Program. 15
4. Aftermarket Parts Program 16
5. Fuels Program, 16
6. Warranties Program. 16
7. Inspection/Maintenance Program. . 17
HI. PROGRESS-IN-EMISSION REDUCTION TECHNOLOGY 18
A. Catalyst Technology. 18
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TABLE OF CONTENTS (continued)
B. Lean-Burn Technology 20
C. Exhaust Gas Reclrculation 21
D. Questor System 21
E. Alternative Engines 22
IV. COSTS AND BENEFITS OF MEETING EMISSION
STANDARDS 23
A. Costs of Meeting Emission Standards 23
1. Passenger Vehicles .. . 23
a. Emissions Control Equipment, 1976 Model Year 23
b. Emissions Control Equipment,, 1977 Model Year 23
c. Emissions Control Equipment, 1978 Model Year 23
d. Maintenance 24
e. Fuel Economy Penalties. 25
f. Light-Duty Trucks. . 27
g. Fuel Cost Increase . . . 27
2. Heavy-Duty Vehicles 29
a. Emission Standards. 29
b. Gasoline Engine Controls. 29
c. Heavy-Duty Diesel Engine Controls. 29
B. Benefits of Meeting Emission Standards 29
1. Air Quality Improvement. 29
a. California 30
bo Philadelphia. 32
c. New Jersey, New York, and Washington State. ....... 33
2. Health Effects of Pollutants Generated
Mobile Sources. 35
a. Methodology of Assessing Benefits. 35
b. Qualitative Assessment of Health Benefits 40
Footnotes
11
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LIST OF FIGURES
Page
III-l OPERATION OF A DUAL BED CATALYST 18
IV-1 COMPOSITE AVERAGES OF SECOND HIGHEST
ANNUAL 1-HOUR OXIDANT VALUES FOR
LOS ANGELES AND SAN FRANCISO 30
IV-2 TOTAL OXIDANTS, NITROGEN DIOXIDE, TOTAL
HYDROCARBONS AND CARBON MONOXIDE
CONCENTRATIONS, PHILADEPHIA (29th and
Race Streets) 34
111
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LIST OF TABLES
Page
I-I EMISSION STANDARDS FOR LIGHT-DUTY MOTOR
VEHICLES 3
1-2 EMISSION STANDARDS FOR HEAVY-DUTY MOTOR
VEHICLES 3
1-3 MAJOR REGULATIONS PROPOSED/PROMULGATED
DURING FY 1975 4
II-l SURVEILLANCE AND COMPLIANCE TESTING OF
VEHICLES AT LOW ALTITUDES 13
II-2 SURVEILLANCE AND COMPLIANCE TESTING OF
VEHICLES AT HIGH ALTITUDES 13
II-3 RESULTS OF ANTI-TAMPERING SURVEY CONDUCTED
BY EPA 14
IV-1 ESTIMATED COSTS FOR EMISSION CONTROL
EQUIPMENT, PASSENGER VEHICLES 24
IV-2 ESTIMATED MAINTENANCE COSTS DUE TO EMISSION
CONTROL SYSTEMS, 1968-1980 PASSENGER
VEHICLES 25
IV-3 EFFECT OF EMISSION CONTROLS ON FUEL
CONSUMPTION OF PASSENGER VEHICLES 26
IV-4 ESTIMATED NATIONAL COSTS ATTRIBUTABLE TO
EMISSION CONTROLS FOR LIGHT-DUTY VEHICLES,
1973-1980 28
IV-5 OXIDANT POLLUTION IN LOS ANGELES AND
SAN FRANCISCO, 1970-1973 31
IV-6 CARBON MONOXIDE POLLUTION IN LOS ANGELES
AND SAN FRANCISCO, 1970-1973 32
IV-7 CO POLLUTION IN SELECTED STATES, 1970-1973 35
IV-8 ADVERSE HEALTH EFFECTS DUE TO EXPOSURE TO
NOx, CO, AND OXIDANTS . 37
IV-9 U.S. POPULATION DISTRIBUTION BASED ON
1970 CENSUS 38
IV-10 ESTIMATED POPULATION-AT-RISK FROM CO AND
OXIDANT AIR POLLUTANTS WITH PRE-EXISTING
DISEASES IN METROPOLITAN AREAS OVER 2
MILLION IN POPULATION . 39
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CHAPTER I. INTRODUCTION AND SUMMARY
The period for this report (July 1, 1974 - June 30, 1975) saw continued
development and refinement of EPA activities to control emissions from new
motor vehicles.
The Energy Supply and Environmental Coordination Act of 1974 enacted
new deadlines for the emissions standards originally established under the
Clean Air Act Amendments of 1970. The Energy Act changed the deadlines
for meeting the hydrocarbon (HC) and carbon monoxide (CO) emission
standards from 1975 (specified in the Clean Air Act) to 1977, with the
possibility of a 1-year suspension. On March 5, 1975, the EPA
Administrator suspended the 1977 HC and CO emissions standards and, as
required by law, established interim standards for the 1977 model year.
The standard for emissions of oxides of nitrogen (NOx) remained at the
interim level previously set by the Administrator. Standards are
summarized in Tables 1-1 and 1-2.
Legislative proposals to revise standards are now under considera-
tion. In March 1975, the EPA Administrator recommended that the
present interim standards of 1.5 grams/mile HC, 15 grams/mile CO, and
2.0 grams mile NOx be extended through 1979 and that a sulfuric acid
emission standard be adopted for 1979 model year vehicles. For 1980 and
1981 model years, the Administrator suggested levels of 0.9 grams/mile
HC, 9.0 grams mile CO, and 2.0 grams mile NOx. In July, 1975, the
President proposed that the present standards be extended through the!981
model year. The Congress is presently considering these and other
proposals for the revision of the statutory requirements for emission
reduction.
The past year saw a number of other developments as EPA:
Continued to support research on effects of motor vehicle
emissions and continued to assess the technology of emission
controls.
Through the recall program, tested vehicles in use and supervised
manufacturer initiated recalls of 428, 558 vehicles that had defective
or deteriorated emission control systems.
ซ Implemented Regulations requiring the availability of unleaded gasoline
needed to protect catalytic converters and making it illegal to sell
unleaded gasoline which is found to be contaminated with lead.
@ Published figures on fuel economy of 1975 model year vehicles
and urged manufacturers to participate in the voluntary program for
labelling new automobiles with fuel consumption data.
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Promulgated regulations requiring that manufacturers demonstrate
compliance with emission standards for vehicles initially to
be sold at altitudes of 4000 feet or above.
Developed a program for ensuring that vehicles driven abroad on
leaded gasoline are properly fitted with operational catalytic con-
verters upon reentry into the United States.
Initiated development of a program of voluntary self-certification for
manufacturers of aftermarket parts which are important to
performance of emission controls.
Proposed the Selective Enforcement Audit method of ensuring com-
pliance with exhaust emission standards at the point of automobile
production.
Held hearings and prepared technical reports on the status of
sulfuric-acid emissions.
Investigated tampering with emissions control systems.
Continued the new car certification testing program.
Continued program of periodic audits of vehicle manufacturers
to ensure that certification procedures are being observed.
Continued development of the short test necessary for implementation
of the performance warranty in Section 207(b) of the Clean Air Act.
The major regulatory actions undertaken by EPA are summarized in
Table 1-3.
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TABLE 1-1
EMISSION STANDARDS FOR LIGHT-DUTY MOTOR VEHICLES
(GRAMS/MILE)
MODEL YEAR
1975
1976
1977
1978
HC CO NOx HC CO NOx HC CO NOx HC CO Nox
LIGHT DUTY PASSENGER
NATIONAL
CALIFORNIA
LIGHT DUTY TRUCK
NATIONAL
CALIFORNIA
1.5
0.9
2.0
2.0
15
9.0
20
20
3.1
2.0
3.1
2.0
1.5
0.9
2.0
0.9
15
9.0
20
17
3.1
2.0
3.1
2.01
1.5
0.41
2.0
15
9.0
20
2.0
1.5l
3.1
0.41
2
3.4
2
0.4
2
1. Waiver granted
2. California will be in compliance with the Federal standards
for 1978 and beyond.
CO
\
TABLE 1-2
EMISSION STANDARDS FOR HEAVY-DUTY MOTOR VEHICLES
GRAMS/BRAKE-HORSEPOWER HOUR FOR HC & NOx;
CQ % OPACITY FOR SMOKE
MODEL YEAR
NATIONAL
CALIFORNIA
1975
HC &
NOx
16
10
CO
40
30
SMOKE l
15, 20, 50
1976
HC &
NOx
16
10
CO ; SMOKE -1
j
40 15, 20, 50
30
1977
HC &
NOx
16
5
CO
40
253
SMOKE 1
15,20.50
HC &
Nox
10 2
5
1978
CO
252
25*
SMOKE 1
15.20.352
1. Diesel only, lugging, acceleration, peak.
2. Recommended
3. Waiver requested.
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TABLE 1-3.
MAJOR REGULATIONS PROPOSED /PROMULGATED
DURING FY 1975
DATE PUBLISHED IN
FEDERAL REGISTER
July 8, 1974
September 10, 1974
October 3, 1974
October 18, 1974
October 21, 1974
October 22, 1974
November 12, 1974
November 12, 1974
December 23, 1974
December 31, 1974
February 27, 1975
March 5, 1975
April 25, 1975
April 30, 1975
REGULATION
STATUS
Regulations for Test Methods to Enforce
Lead and Phosphorus Levels for
Unleaded Gas
Regulations Governing Low-Emission
Vehicle Certification for Light-Duty
Passenger Vehicles
Amendment to Allow EPA to Enter Retail
or Distributor Outlets to Test and Sample
Gasoline to Determine Compliance with
No Lead Regulations
Regulations for High Altitude Certifica-
tion Testing
Regulations Requiring Retrofit of Imported
Catalyst Equipped Vehicles Driven on
Leaded Gasoline
Regulations for Light-Duty Diesel Truck
Emissions
Amendment to Require Submission of
Information Requested by EPA on the
Distribution, Sale, or Delivery of
Unleaded Gasoline
Regulations Requiring Increased Avail-
ability of Unleaded Gasoline in Rural
Counties
Recall Regulations
Regulations for Selective Enforcement
Audit
Amendment of Regulations Governing New
Gasoline-Powered Heavy-Duty Vehicles
Interim Standards for 1977 Model Year
Light-Duty Passenger Vehicle
Defect Reporting Regulations
Regulations Governing Certification
Procedures for 1977 Model Year Light-
Duty Diesel Trucks Offered for Sale in
High Altitudes
Promulgated
Promulgated
Promulgated
Promulgated
Proposed
Promulgated
Proposed
Promulgated
Promulgated
Proposed
Promulgated
Promulgated
Proposed
Promulgated
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CHAPTER II. EPA ACTIONS
A. DECISIONS ON 1977 EMISSIONS STANDARDS
On March 5, 1975, the EPA Administrator granted the request of Ford
Motor Co., General Motors Corp., and Chrysler Corp. for a 1-year
suspension of the HC and CO emissions standards for 1977 model year
vehicles. The original standards were applicable to light-duty vehicles
and engines manufactured during or after the 1977 model year. In reaching
the decision to grant the request, the Administrator considered criteria
specified in Section 202(b)(5) of the Clean Air Act (dealing generally
with the availability of effective technology, the good faith efforts of the
applicants to meet the standards, and the public health and welfare)
and information submitted during 3 weeks of hearings.
The Act also directs that if a suspension is granted, EPA must set
interim standards representing the best available technology. The
Administrator set interim standards of 1. 5 grams per mile of HC and
15 grams per mile of CO for the 1977 model year vehicles. The interim
NOx emissions standard of 2.0 grams per mile, set July 23, 1973, was
maintained.
On the basis of the information submitted during the hearing, EPA
determined that the catalytic technology was available for compliance
with the 1977 standards. However, the oxidative capability that makes
the catalyst effective at converting HC and CO into harmless products
also converts contaminant sulfur in gasoline into sulfuric acid.
An accurate model has not been developed to predict the ambient
concentration of sulfuric acid that will result in the urban and suburban
atmosphere from light duty, catalyst-equipped vehicles. Preliminary
and unverified results indicate that under adverse meteorological
conditions and traffic concentrations, there is a possibility of potentially
harmful ambient levels of sulfuric acid mist along freeways, street
canyons, and other facilities which attract a large number of automobiles.
EPA is concerned, therefore, that, as additional model years of
catalyst-equipped vehicles are introduced, the potential adverse health
effects to sensitive populations from sulfuric acid mist will outweigh
the benefits which catalytic converters provide in the reduction of HC,
CO, and NOx emissions.
Given these potentialities, the Administrator decided that the Nation's
interest would best be served by maintaining the interim standards
until the sulfuric acid question is resolved. The Administrator further
announced that, if possible, a sulfuric acid emission standard will be
issued for the 1979 model year to provide a long term solution to the
sulfuric acid problem. In the meantime, EPA is continuing research
to substantiate the results of preliminary studies.
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With respect to the good faith requirements of the Act, the Adminis-
trator noted that the domestic auto manufacturers had reduced their
efforts at meeting the statutory standards. However, he pointed out that
the industry had developed technology capable of meeting the standards,
even though it might not be the best technology, and that the industry
is not required to spend more than is necessary to meet the standards.
Therefore, he found that the manufacturers had made good faith efforts.
B. WAIVER OF FEDERAL PREEMPTION FOR 1977 MOTOR VEHICLE
EMISSION STANDARDS FOR CALIFORNIA"
On May 20, 1975, the EPA Administrator granted the request of
California to set automobile emission standards for 1977 model year cars
that are more stringent than Federal requirements applicable to cars in
other areas of the country. Section 209(b) of the Act requires that the
Administrator grant such a waiver, after public hearings if he finds that:
The State requesting preemption requires more stringent
standards to meet compelling and extraordinary conditions.
e Such State standards and enforcement procedures are not
inconsistent with Section 202(a) of the Act.
On the basis of these criteria and information submitted at a public
hearing in Los Angeles, California, on April 29, 1975, the Administrator
waived Federal preemption for the 1977 model year and permitted California
to set its HC emissions standards at .41 grams/mile, and its NOx standard
at 1.5 grams/mile. California did not request a change of its present CO
standard of 9.0 grams/mile.
The Administrator found that compelling and extraordinary conditions
existed in California. The Air Resource Board testified that the State
oxidant pollution problem continues to be the worst in the Nation. The
Board presented data demonstrating that the Ambient Air Quality
Standard for photochemical oxidants has been violated in the South Coast
Air Basin at a substantially greater frequency and at significantly higher
concentrations than in any other metropolitan area of the country.
The Administrator also found that technology exists to meet the requested
1977 California standards and that adequate lead time is available to imple-
ment the technology. General Motors and Ford agreed that the standard
could be met, while Chrysler and American Motors were somewhat pessi-
mistic; all asserted that compliance could be achieved only by paying
penalties in the form of high costs, restricted model lines, poorer fuel
economy, and reduced driveability.
The Administrator found that two additional factors strengthened the
basic conclusion that a waiver of Federal preemption was required:
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9 "Basic demand" for new cars could be more easily met in
California because California sales constitute but 10 percent
of the national total; thus greater potential exists for "model
switching" -- that is, each manufacturer has a high proba-
bility of certifying at least one model in each class of vehicles
for California.
The lead time considerations are not necessarily as severe
as the manufacturers stated.
Under California law, manufacturers may delay the introduction of 1977
models until January I, 1977. This could provide up to four additional
months of lead time, depending upon introdiiction dates presently planned.
The Administrator did not view the issue of whether the proposed
California standards would increase emissions of sulfuric acid as a
controlling issue in his decision to grant California a waiver, stating that
"the structure and history of the California waiver provision clearly
indicate both a Congressional intent and an EPA practice of leaving the
decision on ambiguous and controversial matters of public policy to
California's judgment. "
C. MOTOR VEHICLE REGULATIONS
1. Light-Duty Diesel Trucks
Regulations for control of emissions from light-duty diesel-fueled
trucks effective with the 1976 model year were promulgated on October
22, 1974 (39 F.R. 37609). Currently, no such vehicles are known to be
marketed in the United States although several manufacturers are under-
stood to be planning to market such vehicles.
The standards contained in the regulation are the same as those
promulgated for light-duty gasoline-fueled trucks. Manufacturers are
not expected to use special emission control devices or add-on equipment
to meet the standard. Hence, the only additional cost to the manufacturer
will be the cost of certification* The cost per truck cannot be estimated
at this time due to lack of projected sales data,
2. Light-Duty Diesel Trucks in High Altitudes
Regulations for control of emissions from light-duty diesel trucks
designed for initial sale at high altitudes, effective with the 1977 model
year, were promulgated on April 30, 1975 (40 F.R. 18778), High
altitude is defined as any elevation over 1219 meters (4000 feet). These
regulations are consistent \vith the high altitude regulations for light-duty
gasoline-fueled trucks, light-duty gasoline-fueled vehicles, and light-
duty diesel-powered vehicles,
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The standards are expected to be met without additional hardware or
tooling costs, so the only additional cost will be for certification. Lack
of data on projected sales for light-duty diesel trucks at high altitudes
prevents the estimation of the additional cost per truck at this time.
3. 1977 Model Passenger Vehicles in High Altitudes
Regulations for control of emissions from light-duty gasoline-fueled
vehicles, light-duty diesel vehicles, and light-duty trucks intended for
initial sale at high altitudes, effective for the 1977 model year, were
promulgated on October 18, 1974 (39 F.R. 37299).
In order to meet the standard, manufacturer's costs will increase from
$4 to $19 per affected vehicle, depending upon the method of emission
control.
4. Exhaust Emission Standards for Hydrocarbons
EPA is analyzing comments received in response to an Advance Notice
of Proposed Rulemaking (ANPRM) which would convert the current hydro-
carbon exhaust emission standard from a total to a nonmethane hydrocarbon
basis. The ANPRM (39 F.R. 16904) was published in response to a Ford
Motor Co. petition which stated that catalyst-equipped vehicles tended to have
a greater proportion of methane (a nonreactive and thus nonpolluting
hydrocarbon) in the exhaust than current vehicles. Therefore, Ford Motor
Co. reasoned that an emissons standard based on all hydrocarbons, including
methane, penalized vehicles with catalysts.
Emission control systems which selectively remove more reactive hydro-
carbons could more easily meet an emission standard based only on reactive
hydrocarbons. Advanced systems (for example, dual catalyst) would be
affected most directly by the regulations, especially if all hydrocarbons con-
sidered to be nonreactive (methane, ethane, propane, benzene, and acetylene)
were excluded.
Implementing a reactive hydrocarbon emission standard for mobile sources
would require both development of measurement instrumentation and extensive
testing of 1970 model vehicles to revise the baseline against which the
required 90% reduction in emissions is measured. This effort would
require at least 3 years. A revised emission standard which excluded
methane only and applied only to light-duty vehicles could be implemented
somewhat sooner, but would yield approximately half the benefits mentioned
above.
5. Certification of Low-Emission Vehicles
Revised regulations for certification of low emission vehicles under
Section 212 of the Clean Air Act were promulgated on September 10S 1974
(39 F.R. 32613).
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Section 212 of the Clean Air Act provides for the creation of a Low
Emission Vehicle Certification Board (LEVCB). Upon submission of an
application, the EPA Administrator must determine whether a vehicle
qualifies as having emissions substantially lower than standard levels.
If so, LEVCB then must certify that a vehicle is suitable as a substitute
for any class of vehicles then in use by the Federal Government. Certified
vehicles may be purchased by the Government at premiums ranging up to
100 percent over prices normally paid for equivalent vehicles.
At a meeting on December 2, 1974, however, the LEVCB concluded
that Section 212 in its present form is not likely to result in certification
of any low emission vehicles or to achieve the objectives envisioned by
ts drafters.
Accordingly, the EPA Administrator (Chairman of LEVCB) sent to
Senator Edmund S. Muskie, Chairman, Subcommittee on Environmental
Pollution, Committee on Public Works, a letter containing these recom-
mendations:
The Subcommittee may be well advised to eliminate Section
212 from the Clean Air Act (Alternative 1). Federal agencies
able to integrate electric vehicles into their operations can
already do so without obtaining Section 212 certification.
If the Subcommittee concludes that there should be a Federal
program to introduce electrically powered vehicles, a program
much less cumbersome than that set up by Section 212 should
be employed.
One approach would be to simply authorize funds for the General
Services Administration (GSA) and other Federal agencies to use at their
discretion to cover the added costs of procuring electrically powered
vehicles. GSA advises that to implement such a program it would be
necessary to waive the statutory price limitations imposed by Public
Law 93-381 on purchase of sedan-type vehicles.
6. Importation of Catalyst-Equipped Vehicles
EPA has proposed an amendment to the regulations governing the
importation of motor vehicles and motor vehicle engines (Subpart P, Part
85 of Title 40 of the Code of Federal Regulations). The purpose of the
amendment is to assure that vehicles equipped with catalytic converters,
driven abroad on leaded gasoline, and later imported into the United
States are brought into conformity with U.S. emission standards. This
is necessary because lead poisons the catalyst and adversely affects
emission reduction.
The amended regulations prohibit the importation of catalyst-
equipped vehicles which have been operated outside the United States,
Canada, and Mexico unless the vehicle is:
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Part of a catalyst control program implemented by the
vehicle manufacturer and approved by EPA. This program
will ensure that a poisoned catalyst is replaced following
importation.
ฉ Part of a catalyst control program developed and administered
either by the State Department and the Department of Defense
for their own personnel.
ฉ Entered conditionally under bond posted by the importer
(generally an individual consumer). The vehicle and duty
bond are released once a new catalyst is installed.
Manufacturers with control programs have incorporated them within
existing service programs and estimate the cost to be nominal. An
importer of a car requiring a catalyst change will pay $75 for a pellet
catalyst and $150 to $200 for a monolithic catalyst.
7. Recall
On December 23, 1914, EPA promulgated regulations effective January
22S 1975 requiring that a manufacturer, following notification by the
Administrator that a substantial number of his vehicles do not conform
to emissions standards or regulations, submit a recall plan to the
Administrator (39 F.R. 44369). Further actions relating to these regu-
lations are discussed in Section II-F-2.
8. Reporting of Defecrts^
On April 25, 1975, EPA proposed regulations requiring manufacturers
to report information concerning any emission-related defects they
discover. Each manufacturer would then be required to provide EPA
with advance notice of his plans to remedy such defects.
The Defect Reporting Regulations are designed around the systems
already employed by the industry to identify safety-related defects as
required by the National Highway Traffic Safety Administration. The
proposed regulations do not require a manufacturer to establish a program
to locate emission-related defects but require him to report both the defects
he discovers and his voluntary repair efforts as well.
D. SELECTIVE ENFORCEMENT AUDITING
Under Section 206 of the Clean Air Act, EPA proposes to test new
motor vehicles at the assembly line to determine if they conform with
regulations under which their Certificate of Conformity was issued.
Under the program, called the Selective Enforcement Audit (SEA),
EPA will issue an administrative order requiring that a manufacturer
select and test certain production vehicles. If the test results indicate
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a violation of the Certificate of Conformity, EPA may revoke it. SEA
regulations were proposed in December, 1974. Regulations are scheduled
to be promulgated in FY 1976 after a public hearing.
E. CERTIFICATION AND SURVEILLANCE PROCEDURES
1. Certification Testing
Certification of new passenger cars for compliance with Federal emission
standards began with 1968 model year vehicles. The program includes
testing of prototype vehicles which represent all new motor vehicles sold
in the United States.
EPA requires the manufacturer to submit data from two tests. First,
through the Emissions Fleet Test, prototype fleets are tested at 4000
miles to determine their emissions levels at close to the "break in"
point. Second, through the Durability Fleet Test, fleets are tested at
5000 mile intervals to 50,000 miles to determine the deterioration of the
emission control system. To check manufacturers' data, EPA can and
does require that a vehicle being tested be brought to the EPA laboratory
in Ann Arbor, Mich., for confirmatory tests. Approximately 2200 such
confirmatory tests were conducted by EPA during the period covered by
this report.
During FY 1975, certification of most 1975 model year light-duty
vehicles and light-duty trucks was completed, and certification of 1976
models began. Approximately 50 manufacturers of light-duty vehicles
and trucks applied for certification of about 315 engine families for the
1975 model year. Approximately 240 certificates of conformity were
issued. The two major reasons for engine families not receiving certi-
fication were withdrawal of application and failure to meet certification
standards.
A significant development during the 1975 model year was the certifi-
cation of approximately 160 engine families equipped with catalytic
converters. These families correspond to about 85% of anticipated sales
of light-duty vehicles.
In addition to the requirements for original certification of motor
vehicles, EPA has regulations governing vehicles and engines changed
during production of new models. Approximately 2000 requests for
change in new models were reviewed, and more than 650 tests were
conducted to determine compliance with standards.
Certificates are also issued to cover gasoline-fueled and diesel
heavy-duty (truck-type) engines. In this segment of the industry,
approximately 1,000 emission tests were performed by 25 manufacturers.
EPA monitored the test programs to ensure program integrity. After
the emissions testing, over 100 Certificates of Conformity were issued.
Approximately 300 requests to make changes during mass production of
new engines were processed.
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In conjunction with the Federal Energy Administration, EPA published
fuel-economy data in "The 1975 Gas Mileage Guide for New Car Buyers. "
These data include fuel economy results from EPA testing of emission
certification prototypes. Cold start, city cycle testing began with 1973
model year vehicles. A hot start, highway cycle was added with the 1975
model year. Both agencies also sponsored a voluntary fuel economy labeling
program for new cars.
2. Inspections/Investigation Program
EPA schedules periodic audits of certification procedures used by
vehicle manufacturers and inspects facilities to ensure that certification
procedures are being observed. Also, vehicle assembly plants are
inspected to ensure that new vehicles are assembled in certified con-
figurations. In the past year, EPA conducted 43 in-depth inspections
of vehicle manufacturer and assembly plants. EPA's inspection team
visited 11 foreign manufacturers, all four major domestic manufacturers,
and 12 low-volume manufacturers.
During the past year, EPA also initiated seven investigations of
potential Clean Air Act violations by manufacturers and made one referral
to the Department of Justice.
3. Surveillance Testing
Two kinds of tests were performed on vehicles in use during FY 1975.
The first, known as the FY 1973 Emission Factors Program involved the
testing of 1080 vehicles "as received" in six cities. Its purpose was to
determine the emission levels of autos as they are actually maintained
by their owners.
The second, known as the FY 1973 In-Use Compliance Program,
involved the testing of 1385 well maintained vehicles after a tune-up to
manufacturer's specifications. The purpose of these tests was to determine
the capability of properly maintained autos to meet the emission standards
for which they were certified.
The results of those two test programs indicate that properly main-
tained 1973 and 1974 model cars meet their certification emission standards
on the average; however, 1973 autos, as actually maintained by their owners
do not. Tables II-l and II-2 show that the amount by which the average
automobile exceeds its design standards is small for relatively new cars,
and, as shown by the 1967-1974 average, increases with age or mileage.
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-13-
Table II-l
FY 1973 EMISSIONS AND COMPLIANCE
TESTING OF VEHICLES AT LOW ALTITUDES_!/
EMISSION LEVELS, grams/mile
Precontrol
As maintained by
owners 1967-74 2/
1972
1973
1974
After a tuneup to manufacturer's
specifications 1973
3/
Federal Emission Standards 1972-1974
HC
8.7
5.0
4. 1
3.6
3.0
2.8
3.0
CO
87
61
54
45
36
28
28
NOx
3.5
4.3
4.6
3.4
2.8
2.8
3.1
I/ Below 4000 feet
"2 / Average
]T/ Approximately equivalent standards. Actual emission standards based
on a different test procedure.
Table II-2
FY 1973 EMISSIONS TESTING OF
VEHICLES AT HIGH ALTITUDES !_/
MODEL YEAR EMISSION LEVELS, grams/mile
HC CO NOx
Precontrol
As maintained by
Federal Emission
owners 1967-1974
1972
1973
1974
21
Standards 1972-1974
10.
6.
5.
4.
4.
3
2
2
4
5
2
.0
127
99
91
85
79
28
1.
2.
3.
2.
1.
3.
9
9
3
0
8
1
_!/ Above 4000 feet
2/ Approximately equivalent values. Actual emission standards determined
~~ by different test procedure.
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-14-
F. OTHER EPA PROGRAMS
1. Antitampering Program
Section 203(a)(3) of the Clean Air Act prohibits any manufacturer or
dealer from knowingly removing or rendering inoperative a vehicle's
emission control system following sale of the vehicle to the ultimate
purchaser. During the past year, 15 investigations of potential violations
of the tampering prohibition were conducted. Five new cases were
referred to the Department of Justice for action. The referrals resulted
in prosecutions of four car dealers for removal of emission control
systems; $5700 in fines were collected. EPA is continuing to urge
enforcement of State antitampering statutes, which are applicable to
most commercial auto repair businesses. Approximately 40 states have
antitampering laws, but few are actively enforced.
EPA conducted surveys to determine whether tampering is a significant
problem (Table II-3). The surveys, conducted in cooperation with State
and city motor vehicle departments, consist of a visual check of the
emission control systems of vehicles as they pass through annual
inspection. The results indicate significant tampering.
To encourage mechanics to refrain from tampering with emission
control systems, EPA has emphasized the development of training courses
for emission control tuneup. To aid investigators on tampering cases,
EPA has updated its "Inspectors Guidebook" to include a pictorial display
of emission control systems of 1974 and 1975 domestic and foreign vehicles.
Table II -3
RESULTS OF ANTITAMPERING SURVEY CONDUCTED BY EPA
% of vehicles with major % of vehicles with
SURVEY AREA components of emission missing air/fuel
control system removed limiter caps I/
Washington, D. C. 15 33
New Jersey 15 50
Cincinnati, Ohio 2j 17
1. Suggests degradation of emission control through poorer control of
air -fuel mixture.
2. Not available.
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-15-
2. Recall Program
Section 207(c) of the Clean Air Act requires the EPA Administrator
to notify a manufacturer to recall and repair vehicles of a given type when
the Administrator determines that a substantial number do not conform to
applicable emission standards during their useful lives. The objective is
to provide incentives to manufacturers to build vehicles which conform
with emission standards for 5 years or 50, 000 miles of actual use.
The recall program consists of surveillance and investigation,
recall order implementation, and public reporting.
Surveillance is comprised of Federal in-use vehicle testing, defects
reporting from government and commercial fleets, review of data from
State and local inspection/maintenance programs, other emission test
results, consumer complaints, and manufacturer's defects reporting.
As a result of surveillance activity during part of FY 1975 12 manufacturer
initiated recalls and one ordered campaign were completed; 428,558 vehicles
were affected. To date 1,514, 933 vehicles have been recalled to correct
emission-related nonconformities. Twelve investigations initiated in FY
1975 are continuing.
Public reporting of recall campaigns instituted under the Clean Air
Act will be initiated in FY 1976. By issuing periodic reports of emission
recall campaigns, EPA hopes to establish communication with the public
on the compliance of in-use vehicles with the Clean Air Act. Not only
will the public receive valuable information on the vehicles subject to
recall, but, through exposure to the existence of such campaigns, public
participation will be encouraged as well.
3. Imports Program
In conjunction with the U.S. Customs Service, EPA monitors imported
vehicles to ensure that they conform with U.S. emission standards. Those
not conforming may be imported under a U. S. Customs bond pending modi-
fication of the vehicle to meet the standards. Vehicles that can not be
modified to conform must be exported or destroyed.
EPA periodically vists Customs ports in the United States to inspect
imported vehicles, and to meet with customs officials concerning enforce-
ment of the joint EPA-Customs regulations. During the past year, EPA
made at least one visit to 36 ports of entry in the United States. EPA
monitored entry ^f approximately 200,000 commercial and privately owned
vehicles, issued orders which resulted in 314 vehicles being modified to
conformity and exported 68 nonconforming vehicles. 152 vehicle owners
were penalized by Customs in the amount of approximately $411,000 for
not complying with the joint EPA-Customs regulations,,
EPA initiated 80 investigations of potential violations of the import
provisions of the Act. One of these cases was in referred to the
Department of Justice. In some of the remaining cases, Customs was
requested to assess civil penalties against the vehicle owners.
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-16-
4. After-market Parts Program
On November 14, 1974, EPA published in the Federal Register an Advance
Notice of Proposed Guidelines describing a program of voluntary self-
certification for manufacturers of automotive parts for replacement of
defective or worn-out emissions control systems. The proposed aftermarket
parts program will attempt to develop certification standards that will enable
manufacturers to design and build their parts in conformity with the standards.
The manufacturer would then be able to advertise the aftermarket parts as
being on a par with the original equipment they replace. The program is
intended to help alleviate any adverse competitive impact of the emission
control warranty by providing an objective basis for ensuring that after-
market parts do not degrade performance. EPA is working closely with
the aftermarket industry to develop acceptable procedures for testing.
5. Fuels Program
In order to protect catalytic converters from debilitating contamination
caused by lead in gasoline, EPA is authorized under Section 211 of the
Clean Air Act to regulate the lead content of gasoline to be used in cata-
lyst-equipped vehicles.
EPA has established a field sampling inspection system to assure the
general availability of lead-free fuel at the retail outlet. Each of EPA's
10 Regional Offices has a mobile fuels test laboratory to sample and test
lead-free gasoline at the retail outlets. All tests indicating contamination,
plus 10% of all field samples, are sent to the laboratory. A control program
has been implemented to monitor the quality of laboratory and field analyses.
Each Region inspected 1,000 to 2,000 retail outlets during FY 1975. In
total, 17, 000 samples of unleaded gasoline were collected and analyzed
by EPA personnel. In addition, more than 3, 649 notices of violation were
issued for minor violations and over 300 formal complaints assessing penalties
issued for more serious problems.
States are being encouraged to sample lead-free gasoline and to adopt
lead-free gasoline regulations. During FY 1976, at least seven States will
inspect unleaded gasoline under contracts with EPA.
6. Warranties Program
Section 207(a) of the Clean Air Act provides for a defects warranty
starting with the 1972 model year. The warranty provides that when through
no fault of the owner, an automobile fails to comply with applicable emissions
standards, the manufacturer must remedy such nonconformity and bear the
costs. EPA has concluded that consumers do not understand this warranty,
which is contained in all owner's manuals, and, therefore, are making
few claims under it. To overcome this difficulty, EPA will soon publish
an Advance Notice of Proposed Rulemaking (ANPRM). ANPRM includes
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-17-
two lists --a "defects" list and an "emissions control system" list. Defects
(specified failure modes of specified emissions-related parts) would be
presumed to cause emission standards to be exceeded and would thus be
covered by the warranty. The emissions control system list would include
all parts which, if they fail, could potentially cause the vehicle to exceed
standards and thus be covered by the warranty. Under regulations proposed
in this ANPRM, EPA intends to monitor the vehicle manufacturers' efforts
under the warranty.
The 207(b) performance warranty of the Clean Air Act, running from
initial to ultimate purchasers cannot be implemented until EPA develops
a short test which reasonably correlates with the sophisticated Federal
Test Procedure used on prototypes of new vehicles. At the present time
EPA is continuing its efforts to develop a short test and has set as a target
date for implementation the 1978 model year.
1, Inspection/Maintenance
Inspection/Maintenance (I/M) of in-use vehicles is intended to cause
the public to realize more fully the benefits of the emission controls installed
on their vehicles. The program consists of either measurement of emissions
while the car is running in neutral or a dynamometer test which measures
emissions during a simulated short driving cycle. Development work
for the program began in 1971 with EPA studies undertaken to determine
the emission reductions associated with State Implementation Plans pursuant
to Section 110 of the Clean Air Act, I/M programs are required in
28 areas of the country as part of a State Implementation plan for meeting
auto related primary standards. Seven States (or local areas) have programs
either underway or nearly underway. Seven notices of violation have been
issued to jurisdictions failing to take steps necessary to implement I/M
programs. Implementation is expected to increase in the future as
institutional steps necessary to implement the program (legal changes,
construction of facilities* etc. ) are accomplished.
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-18-
CHAPTER IE. PROGRESS IN EMISSION REDUCTION TECHNOLOGY
A. CATALYST TECHNOLOGY
Several types of catalytic converters are presently in use or under develop-
ment. The oxidizing catalytic converter, a device in the exhaust stream, which
stimulates oxidation of unburned fuel, changes HC and CO emissions into
harmless carbon dioxide (CO2)and water. The reducing catalytic system
stimulates conversion of NOx into nitrogen gas (N2^
These two converters can be combined in a dual-bed system. Figures 111-1).
In such a system, the exhaust first passes through a reducing catalyst where
NO is transformed into N 2 and small amounts of ammonia (NH ). The exhaust
then passes through an oxidizing catalyst where CO and HC are changed into
CO and H^Q, and the small amounts of ammonia are oxidized to NOX
Figure ml. Operation of * Dual-ied Catalyst
INTAKE
AIR & FUEL
UNTREATED
EXHAUST
REDUCING
CATALYST
TREATED
EXHAUST
}
V
CO + HC +
N-, + NHo
OXIDIZING
CATALYST
FINAL
EXHAUST ,
CO, + H,O +
N2 + /CO + HC + NO
I WITHIN LEGAL
\L1MITS
The final basic catalytic system is the three way catalyst in which
HC, CO, and NOx are converted in one catalyst bed.
A problem with the widespread use of present catalyst systems
is that they may emit sulfuric acid in concentrations that are projected to be
a possible threat to the public health. For this reason, EPA contracted
with Exxon Research and Engineering Co. to investigate various means for
control of sulfuric acid emissions from catalyst-equipped motor vehicles.
The most promising technology to date is the three-way catalyst
reformulation (using different metals in the catalyst), combined with the
control of excess air in the catalyst. Widespread use of the three-way
catalyst is not expected to be feasible until 1979-80, due to the long
production lead times required for the very precise fuel metering needed
with these systems. In addition, the durability of these systems continues to
require investigation.
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-19-
Exxon also identified chemical traps using a calcium-oxide-based
absorbent as a potentially effective sulfuric acid and sulfate control method;
the initial design tested by Exxon revealed, however, that with extended use,
the trap when properly placed in the exhaust line, tended to restrict exhaust
flow and, therefore, resulted in increased exhaust back pressure. This
increase is undesirable because of its effect on overall engine efficiency.
Further research and development are needed if a satisfactory trap is to
be produced.
Other problems accompanying the widespread use of catalytic converters
include objectionable odors and the possibility of overheating or fires.
The primary odorous material is believed to be hydrogen sulfide, formed
in the catalyst from sulfur in the gasoline, usually during engine idling
conditions, when the air-fuel mixture in the carburetor has become too rich.
Vehicle manufacturers have informed EPA that these odors should be
eliminated if the carburetor is adjusted within the manufacturers' specified
limits and other sources of rich mixtures (clogged air filter) are repaired.
With respect to catalyst overheating, the information available to EPA
indicates that if the engine is running properly catalyst surfaces are no hotter
than surfaces of exhaust systems containing no catalyst. However, if there
is a partial failure of the ignition system, such as misfiring spark plugs,
catalyst temperatures may rise to over 1200 F because of the abnormal
amount of fuel delivered to it by the non-firing cylinders. In most catalyst-
caused fires reported to EPA, the vehicles involved have been found to be
running badly.
Currently, EPA is cooperating with the U. S. Forest Service to evaluate
the possibility that vegetation fires in the National Forests and Parks are
caused by hot exhaust systems, both catalytic and noncatalytic. In addition,
EPA is cooperating with the National Highway Traffic Safety Administration
in obtaining information as to measures being taken by the manufacturers
to minimize the likelihood that vehicles equipped with catalysts will increase
fire hazards. Further, EPA has publicly urged that vehicle manufacturers
install temperature sensors on their catalysts which will activate lights
and buzzers to warn the driver that the catalyst has overheated. Such
devices may not only reduce fire hazards, but could, in addition, save
fuel and control emissions better since higher-than-usual catalyst
surface temperature usually indicates engine malfunction.
Less than optimal control of the basic engine operating parameters
(especially air-fuel mixture control) has, in the past, led to catalyst
deterioration, attrition (loss of catalyst material), and formation of ammonia.
Refinements in reduction catalysts and dual catalyst systems have,
however, resulted in catalyst systems with greater tolerance for less than
ideal operating environments. In one such refinement, developed by Gould
Inc., an oxygen removal catalyst or "getter" is added to Gould's metallic
dual catalyst system; this eliminates the occasional overly lean mixtures
(too great a percentage of air in the air-fuel mixture) that cause deterioration
of the NOx catalyst itself. By controlling air-fuel mixture in this way,
catalyst-engine matching has been significantly improved. The Gould system
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-20-
has demonstrated NOx levels close to 0.4 during durability tests of over
25, 000 miles. When used in conjunction with advanced engine modifications
and exhaust gas recirculation systems, (see ง111-3), certification to the
statutory 0.41/3.4/0.4 levels may be possible, provided the catalyst is changed
at 25,000 miles. An unresolved issue with the Gould system is particulate
emissions. Preliminary data suggest some attrition or loss of metal in the
nickel-based catalyst is occurring when cars equipped with the Gould system
are run on gasoline containing moderate amounts of sulfur. Additional
testing is necessary to assess the extent of this potential problem.
Catalyst-engine matching has also been significantly improved by feedback
control systems that closely control air fuel ratios. Oxygen sensors, which
respond to excess oxygen in the exhaust gases, can signal the carburetor
or the fuel injection system to control the ratio. To date, fuel injection systems
have provided the most rapid and accurate response. When the excess oxygen
in the exhaust is closely controlled by a feedback system, it is possible either
to extend the life and efficiency of a NOx catalyst, or to convert simultaneously
HC, CO, and NOx in one catalyst bed (three-way catalyst).
Prototype exhaust sensors with 20,000 mile life and modest ($5) replace-
ment costs are now available. Two problems remain with the feedback approach:
No three-way catalyst has yet been able to maintain
0.4 NOx levels at high mileage in a standard vehicle.
The costs of fuel injection systems are much greater
than the costs of carburetors, and U. S. manufacturers
are hesitant to bear this added cost in addition to the
already increased costs of other necessary emission controls.
Even if the durability problems with reducing or three-way catalysts are
solved, it appears that the cost of any technology capable of meeting the
0.4 NOx standard will be high. Initial costs are estimated to range between
$350 and $550 for systems meeting the full statutory standards, compared to
estimated costs of $200 for the typical 1975 oxidation catalyst system.
B. "Lean Burn" Technology
Engines calibrated for very lean air fuel ratios achieve low emissions of CO,
HC, and sulfuric acid even without a catalytic system. An advanced form of "lean
burn" technology would utilize various sensors, including an oxygen sensor, a mini'
computer, and feedback circuits to optimize spark timing, exhaust gas recircu-
lation rate, air-fuel ratio, and transmission shift points. These improvements
might cost no more than present catalyst technology and would control emissions
to the 1975 California levels (0.9/9.0/2.0) with little or no fuel economy decrease
compared to uncontrolled cars. However, to achieve emissions much below these
levels, a catalyst will most likely be needed in conjunction with some or all
of the "lean burn" system components. At present, one domestic manufactuer
is actively considering full scale production of lean burn type vehicles.
The Dresser carburetor is one of the major developments in air-fuel
mixture control. Its primary application to date is in lean burn engine
systems, although it is compatible with other systems. It achieves a high
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-21-
degree of fuel atomization by use of high speed air flowing through a variable
area venturi. The Dresser system produces an unusually homogeneous air-fuel
mixture. This overcomes much of the cylinder-to-cylinder variation in air-fuel
ratio which hampers current attempts to operate engines with very lean air-fuel
mixtures. The Dresser carburetor's ability to control air-fuel ratios may enable
it to be used with three-way catalysts, thus providing an alternative to expensive
fuel injection systems.
C. Exhaust Gas Recirculation
Recirculating exhaust gas through the intake system controls NOx emissions
by reducing the peak combustion temperature. The exhaust gas, an inert
substance, does not contribute to the combustion process. Refinements have
been made in the laboratory to exhaust gas recirculation (EGR) systems,
with the most significant recent work being that of Gumbelton.l/ He reported
an EGR system which resulted in 1. 0 gpm NOx levels from fulTsize cars
without fuel economy penalties. However, the conditions that promote low
NOx emissions also promote high HC emissions. Achieving low NOx emissions
control can increase HC emissions to the point that 0.41 HC standard
becomes tougher to meet than the . 4 NOx standard.
It is clear that optimum EGR operation will require more sophisticated
systems than are available on current cars. Work on electronically modulated
EGR and spark timing systems has been reported as encouraging in the
laboratory, but there have been no commitments to produce such systems.
D. Questor System
The "Questor" system combines high temperature oxidation of HC and
CO with catalytic reduction of NOx and has shown considerable potential for
achieving the 0.41/3.4/0.4 standards. In tests (on standard size cars) by
several manufacturers, emissions were reduced below the standards. Problems
remain, however, with the degree of mixture enrichment required and high
temperatures necessary to achieve adequate control of HC, CO, and NOx.
The rich mixtures used with the Questor system increase fuel consumption
and exhaust temperatures, which degrade the system with use. Over 3 years,
however, the fuel economy associated with the Questor system has been
improved to a position of parity with 1974 models (13% lower than 1975
models).
E. Alternative Engines
Several alternatives to the conventional internal combustion engine are under
development and may have some bearing on emissions in the next few years.
The stratified charge engine employs a layered fuel mixture in the
combustion chamber. The idea is to keep a fuel-rich mixture near the point
of ignition inside the cylinder while keeping the rest of the mixture lean.
Honda's CVCC stratified charge engine uses a small-volume, fuel-rich
prechamber at the fuel ignition point, with the main combustion chamber
containing a fuel-lean mixture. The CVCC principle has been shown capable
-------
22
of bringing even full size cars into compliance with 0.41/3.4/2.0 levels with
essentially no increase in fuel consumption over average 1975 cars. Using
spark retard and EGR, NOx can be lowered to 0.25 on small cars providing
adequate cushion to meet a 0.4 standard. A problem at this calibration
level is fuel consumption which, in the initial testing, was increased by
about 20%.
Ford's Proco stratified charge engine employs an open combustion chamber
differing from the Honda prechamber system. The Proco can achieve 0.4 NOx in
4500-pound cars without catalytic control of NOx because of the combination of
stratified charge combustion and high EGR. HC emissions, rather than NOx
have presented the greatest problem. While the Proco vehicle can simultaneously
achieve 0.41/3.4/0.4 with oxidation catalysts, HC levels have exceeded 0.41 prior
to 25,000 miles at the 0.4 NOx calibration. In an uncontrolled state, the Proco
engine uses substantially less fuel than conventional engines, but it has high HC
emissions. Reducing HC levels has so far required throttling, which makes the
engine's fuel consumption comparable to conventional engines. Once throttling
is used to control HC emissions, further measures, such as EGR to lower NOx,
have little effect on fuel consumption. At present, there are no production
versions of the Proco engine.
The rotary engine uses rotating drive elements to replace the reciprocating
pistons currently used in internal combusion engines. Toyo Kogyo has made
major improvements in control technology for engines in the past 5 years.
Current stratified-charge rotary engine prototypes show potential for meeting
the 0.41/3.4/0.4 standards. Prototypes have achieved 0.33/1.7/0.38, while
consuming less fuel than current 1974 and 1975 production versions of the engine.
Diesel engine passenger cars currently produced by several manufactuers show
potential for meeting the 1978 standards. Greater use of diesel engines in passenger
cars continues to be studied by industry. At this time, it appears that diesel-
powered passenger cars can be designed to achieve emission levels of 0.41 HC and
3.4 CO, with NOx levels in the range of 1.0 to 1.5. The prospects for meeting
0.4 NOx with a diesel automobile are not known, due to limited developmental
efforts, but are considered unlikely.
During the period covered by this report, the Federal program on alternative
automotive power systems, was transferred to the new Energy Research and
Development Administration. The projects on Rankine cycle, gas turbine, and
Stirling cycle engines started under EPA will be redirected and in some cases
expanded in response to the energy conservation mission of that agency. While
these systems continue to offer long-term potential for meeting very low
emission standards, their large-scale manufacture will be later than any of the
other systems discussed here certainly post-1980.
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-23-
CHAPTERIV. COSTS AND BENEFITS OF MEETING
EMISSION STANDARDS
A. COSTS OF MEETING EMISSIONS STANDARDS
1. Passenger Vehicles
a. Emissions Control Equipment, 1976 Model Year
Because the 1976 emissions standards are the same as the 1975
interim levels, only minor changes in control systems will be made
from 1975 models and, thus, no increased cost is attributed to the
1976 model year emission control equipment. Estimates of the
equipment or engine modification costs per car for 1976 emissions
control equipment over baseline (pre 1968) vehicle costs are:
e EPA -- $200
NAS -- $159
Industry -- $100 - $450
b. Emissions Control Equipment, 1977 Model Year
With the suspension of the statutory 1977 emissions standards,
the automobile manufacturers should be able to meet the interim 1977
standards with minor engine and control device modifications.
The interim standards are the same as the 1975/76 standards for
HC and CO. The 1977 standard of 2.0 grams/mile NOx is 35 percent
lower than 1975/76 level. The needed engine modifications could take
the form of improved EGR systems. EPA estimates that the
incremental cost of meeting the 1977 standards is $20 per vehicle.
c. Emissions Control Equipment, 1978 Statutory Standards
Additional technology will be required to meet the full statutory Federal
emission standards. Systems which involve modification of conventional
internal combustion engines have shown capability of meeting the 1978
standards at low mileage. Dual and three-way catalysts are considered
the most advanced of the systems being investigated. Estimates of the
cumulative initial costs of meeting the 1978 standards are:
ซ EPA -- $470
* NAS -- $304
ซ Industry -- $315 - $950
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-24-
Table IV-1 summarizes the estimated cost of meeting the emissions
standards for 1968-1980 model years. For 1979 and 1980, the incremental
cost of added emission control equipment is expected to be minimal.
TABLE IV-l. ESTIMATED COSTS FOR EMISSION CONTROL
EQUIPMENT, PASSENGER VEHICLES
List price (December 1974 dollars)
27 2T" 3/
Model year standards EPA~ NAS~ Industry
Cumulative costs 100 84 50-120
through 1974
1975/76 incremental 100 75 50-330
costs
1978(full statutory standards)
incremental 20 -- 4_/ --jj
costs
1978 incremental 250 145 215-500
costs
Cumulative costs 470 304 5_/ 315-950 5/
through 1980
T7 Includes~dealer and factory profits.
~2_/ Data obtained primarily from "Automobile Emission Control--The
~~ Technical Status and Outlook as of December, 1974", a Report
of the EPA Administrator, January 1975.
3_/ Data submitted by domestic manufacturers.
ฅ/ Data not available.
57 Includes a "zero" value for data not available in 1977.
d. Maintenance
Maintenance costs for emissions control systems are expected to
fluctuate for 1975-1980 model vehicles. The increasing complexity of
the systems will cause increased maintenance costs. There are, however,
certain benefits in reduced maintenance cost derived from the use of high
energy ignition systems, increasingly durable exhaust systems and unleaded
fuel.
Changes in annual maintenance cost for the various model years
are shown in Table IV-2.
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-25-
TABLE IV-2. ESTIMATED MAINTENANCE COSTS DUE TO
EMISSION CONTROL SYSTEMS, 1968-1980
PASSENGER VEHICLES
Changes in annual maintenance cost per vehicle
1968-1974 +$16
1 2
1975-1977 -$7 (December 1974 dollars)
3
1978-1980 +$6 (December 1974 dollars)
_]./ Assuming that 85% of vehicles sold in 1975 will be catalyst
equipped, 80% in 1976, 75% in 1977.
2_/ Assuming oxidation catalysts used all three years and based on
standards of 1. 5 HC, 15CO, 3.1 NOx (1975-76 models); 2.0 NOx
1977 models.
3_l Assuming use of oxidation catalysts and based on statutory
standards of 0.41 HC, 3.4 CO, and 0.4 NOx.
Source: The Cost of Clean Air 1975--Annual Report of the Administrator,
1975, unpublished draft.
e. Fuel Economy Penalties
The average fuel economy of motor vehicles has decreased
gradually over the past few years (up to 1974 model vehicles). This
decrease is due in part to vehicle weight and optional equipment,
but emissions control mechanisms such as EGR and retarded
ignition timing also adversely affect fuel economy.
Fuel penalties for the 1968 model years are obtained from an
EPA study of nearly 4,000 passenger cars, from 1957 production
models to 1975 prototypes. For 1973 model cars economy
decreased 10.1 percent over pre-1968 cars. For the 1974 models,
fuel economy decreased 10.4 percent over the pre-1968 baseline,
based on estimates from 1974 certification data and sales data for
the first 6 months, A shift toward lighter cars was observed in the
first 6 months' sales, but the trend was reversed for the remainder
of the year.
Industry sources as well as EPA, have indicated that fuel
economy on vehicles equipped with catalysts increased compared to
1973 and 1974 model year cars. When weighted for estimated sales,
EPA's 1975 vehicle certification data showed a increase in economy of
approximately 1 percent over pre-1968 cars.
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26
An additional fuel savings, of about 12 percent compared to 1975 MY
cars, is anticipated for the 1976 model year. No change from 1976
figures is expected for the 1977 model year. However, meeting the full
statutory standards would mean that fuel economy may decrease 15-20
percent compared to 1976 MY cars, in the first year of implementation.
This fuel economy loss would be due primarily to the stringent NOx
emission control standards, for which control technology has not yet been
demonstrated. In subsequent years, as emission control technology is
further refined, it is probable that the fuel penalty will be reduced to the
point of 1976 levels.
These estimates of future fuel economy note only the changes due
to emission controls. Separate industry efforts to improve fuel
economy, such as reduction of size and weight and improvement
of engine efficiency, will increase fuel economy of all affected models.
The effect of emission controls on passenger-car fuel economy for
the period 1968 to 1970 is summarized in Table IV-3.
TABLE IV-3.
EFFECT OF EMISSION CONTROLS ON FUEL
ECONOMY OF PASSENGER VEHICLES
Model Year Standards
Yearly Incremen-
tal change in
fuel economy,
percent
Fuel economy
penalty over
baseline, percent
I/
1957-67
(Uncontrolled)
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
- 4.2
- 1. 9
+ 2.4
- 2.4
- 1.5
- 3.0
- 0.3
+ 13.5
+ 12.0
0.0
- 15 to 20%'
4.2
5.9
3.9
5. 9
7.3
10. 1
10.4
-1.7
-13.9
-13. 9
3.2-8. 9*
T7 Baseline city fuel economy of 196~T~mbdel year car = 13.5 miles/
gallon. All percentages shown are based on Urban Cycle Fuel
Economy tested on the 1975 EPA Federal Test Procedure.
Office of Mobile Source Air Pollution Control, March, 1976
Source:
data.
Statutory standards in effect for 1978 as of June 30, 1975 were
0.41 HC, 3.4 CO, 0.4 NOx (all gm/mi. ). Standards being re-
considered by Congress; any modification will affect fuel economy
of all vehicles.
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-27-
f. Light-Duty Trucks
For this report, emission control equipment costs for 1973 and
1974 model year light-duty trucks (under 6,000 pounds gross vehicle
weight) are assumed to be the same as for passenger cars for 1973
and 1974--that is, $87 per car in current dollars. Standards less
stringent than those for passenger vehicles were set for light-duty
trucks beginning with the 1975 model year; consequently, it is assumed
that emission control costs for model years 1975-1980 will be only
moderately higher than for the 1973-74 years ($150 per car in December
1974 dollars).
Annual incremental maintenance costs for emission controls on 1973
and 1974 model year light-duty trucks are estimated to be $16 per vehicle.
For the 1975 to 1980 model years maintenance cost will decrease an
estimated $10 per vehicle due to the use of catalysts, low-maintenance
emission-control components, and unleaded fuel in a significant portion
of light-duty trucks sold.
Fuel economy of light-duty trucks is expected to be the same as for
light-duty passenger cars for 1973 and 1974. Fuel consumption is
estimated to decrease 6 percent for the 1975 model year, and no further
emissions related change is expected for the 1976 to 1980 period.
g. Fuel Cost Increases
On January 10, 1973, EPA promulgated regulations requiring that by
July 1, 1974, gasoline marketers make 91 research octane number, lead-free
gasoline generally available for use in vehicles equipped with lead-sensitive
control systems. At the same time, for the purpose of public health,
EPA proposed regulations requiring that the lead content of leaded
gasoline be reduced to an average of 1. 25 grams per gallon (gpg) by
January 1, 1978. On November 28, 1973, EPA promulgated revised lead
regulations providing for a phased reduction in the average lead content of
all grades of gasoline produced by any refinery over a 4-year period.
Refineries were to be restricted to 1. 7 gpg beginning January 1, 1975,
with annual reductions to bring the level to 0.5 gpg by January 1, 1979.
A court decision set aside the 0.5 gpg by 1979 regulation making it
difficult to determine what the lead standards will be. For this report,
the lead phase-down is assumed to take place as directed in the revised
regulations.
The cost per gallon of fuel due to the lead regulations is expected to
increase by 1. 09 cents for 1975 and 1976, 1. 3 cents for 1977 through
1979, and 1.5 cents for 1980.
The total costs for light-duty vehicles due to emissions controls
and lead regulations are summarized in Table IV-4.
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TABLE IV-4 ESTIMATED NATIONAL COSTS - ATTRIBUTABLE TO
EMISSION CONTROLS FOR LIGHT-DUTY VEHICLES1, 1973-1980.
(BILLIONS OF DOLLARS)
CALENDAR
YEAR
1973
(Incremental)
1974
( Incremental)
1975
(Incremental)
1976
( Incremental)
1977
( Incremental)
1978 i/
(Incremental)
EQUIPMENT
1.00
. 76
1.64
2.06
2.46
4.89
MAINTENANCE- FOR
LIGHT-DUTY VEHICLES
.94
1.07
.99
.86
.71
.69
INCREASED FUEL
CONSUMPTION2
1. 36
2.37
2.29
1.93
1.38
1.29
FUEL PRICE
INCREASE3
-
-
.60
.63
.77
.93
ANNUAL
TOTAL
3.30
4. 20
5.52
5.48 1
r-
oo
1
5.32
7. 80
1. Vehicles under 6000 pounds gross vehicle weight.
2. Fuel prices assumed (cents.gal): 1973, 41.6; 1974-75, 55; 1976, 61; 1977, 63; 1978, 65, 1979. 67;
1980,69; this penalty will obviously increase further due to the increase in gasoline prices.
Current prices are already in excess of assumed figures.
3. Increases due to lead regulations (cents/gal): 1975-76, 1.09; 1977-79, 1.3; 1980, 1.5.
4. Current dollars used 1973-74; December 1974, dollars used 1975-80.
5 . Assumes full statutory standards.
SOURCE - Cost of Clean Air Act 1975 - Report of the Administrator, 1975, unpublished draft.
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2. Heavy-Duty Vehicles
a. Emission Standards
Separate emission-control regulations have been in effect since 1970
for new heavy-duty gasoline and diesel truck engines manufactured for
use in over-the-highway trucks and buses of over 6000 Ib. gross vehicle
weight. Trucks under 6000 Ib. gross vehicle weight are considered light-
duty vehicles and have been dealt with in the previous section of this
report.
b. Gasoline Engine Controls
Through 1973, the emission control technology used for heavy-duty
gasoline engines was similar to that employed for light-duty vehicles
through the 1972 model year. For this reason, and because EPA has
made no detailed equipment cost estimates of heavy-duty gasoline truck
engine controls, this report assumes that the per-vehicle cost increment
for control equipment on 1970-1973 engines is equal to that for 1972
passenger-car engines, minus the cost of fuel evaporation controls.
The equipment cost is estimated to be $24 per vehicle. For model
years 1974-1980, it is assumed that equipment costs will be equivalent
to 1973 passenger cars control costs, minus the cost of EGR and evaporative
controls. For 1974 and beyond, therefore, the equipment costs are
assumed to be $50 per vehicle.
Annual incremental maintenance costs for heavy-duty gasoline
engine controls for 1968-1980 are assumed to be equivalent to the
passenger car cost for 1968-1974, or $16 per vehicle.
Fuel consumption penalties are estimated to be 3 percent for 1970-73
period and 5 percent for 1974 and beyond. The baseline fuel economy
is assumed to be 8.5 miles per gallon.
Total cumulative estimated annual costs for heavy-duty gasoline
truck emission controls for the period 1970-1980 are $4.59 billion.
c. Heavy-Duty Diesel Engine Controls
Emission standards for smoke, HC, CO, and NOx, including those for
1974, have been attained largely through modifications to the fuel injection
system. NOx and smoke are the most difficult emissions to control. (Even
uncontrolled diesels are usually well within CO standards). Equipment cost
penalties are considered nominal. Further, it is estimated that no fuel
consumption penalties have been incurred. Accordingly, at this time, no
national cost penalty is attributed to diesel-truck engine emission controls.
B. BENEFITS OF MEETING EMISSION STANDARDS
1. Air Quality Improvement
The pollutants of concern in this report are CO, HC and NOx generated
by mobile sources and their relationship to ambient exposures to CO,
Oxidant (of which HC is a precursor), and NO (of which NOx is a precursor).
2
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Trends will be discussed for specific areas because there are insufficient
historical data to examine national trends. The analyses of specific areas
are based on data from the National Aerometric Data Bank (NADB) as well
as trend summaries from several State and local reports. While different
criteria were used for the NADB, State, and local analyses, data cover
a 3 year period at a minimum.
The available information presents a somewhat mixed picture. Progress
is being made in achieving the NAAQS for oxidant and CO in the Los Angeles
Air Basin, the San Diego Air Basin, the San Francisco Air Basin, and in
Sacramento. In Philadelphia, total oxidants declined from 1965 through
1972 with a somewhat unexplained increased trend from 1972 into 1974. While
there is no clear trend in CO in Philadelphia, progress is being made in
achieving the 8-hour CO NAAQS in New Jersey, New York, and Washington
States.
HC levels are decreasing in the Los Angeles Air Basin and are unchanged
in San Diego and Philadelphia. In contrast NOx levels are increasing in
the Los Angeles Air Basin and Philadelphia and are relatively unchanged in
San Diego.
a. California
Oxidant, nitrogen dioxide, and hydrocarbon. California oxidant data from
NADB are examined for coastal Los Angeles, noncoastal Los Angeles, and
the San Francisco Bay Area. In general, oxidant trends for the three groupings
confirm the longer-term downward trends perviously reported. This improve-
ment can be seen in both the magnitude of peak hourly concentrations of oxidant
(Figure IV-1), as well as the number of values above the 1-hour National Ambient
Air Quality Standards (NAAQS) (Table IV-5).
i
FIGURE IV-1. Composite averages of second highest annual 1-hour oxidant
values for Los Angeles and San Francisco, 1970-1973
G
CD
O
G
O
U
U>o
foo
-400
300
lit
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TABLE IV-5. OXIDANT POLLUTION IN LOS ANGELES AND
SAN FRANCISCO, 1970-1973
Area
Number of
Sites
Average annual number of values above 1-hour
NAAQS oxidant standard I/
1970
1971
1972
1973
Coastal Los Angeles
Noncoastal
Los Angeles
San Francisco
Bay Area
4
5
309
886
110
202
768
77
188
698
80
299
703
49
_!/ 160 mg/m3.
Source: National Air Data Bank.
A notable deviation from the general pattern of decline in concentrations
did occur, however, at four coastal sites in Los Angeles. The California
Air Resources Board, in its report, "California Air Quality Data, January
through March 1973" states that under the influence of extensive warm air and
high pressure aloft, two oxidant smog episodes developed in the south coast
air basin in June 1973. In addition, the frequency of there adverse conditions
was unusual--high pressure aloft occurred on 20 days in June as opposed to
a long-term mean occurrence of 8 days. (This emphasizes the potential
impact of adverse meteorological conditions. ) These conditions contributed
to the slight increase in number of annual violations of the 1-hour NAAQS that
occurred within the Los Angeles Basin during 1973.
The sites selected from the San Francisco Bay area have improved
in both the second highest annual maximum and in the number of observations
exceeding the NAAQS. The Bay Area Air Pollution Control District states,
however,- that the downward trend in oxidant concentration has leveled off
somewhat since 1971.
Overall the general pattern seems to be one of the modest improvements
in peak oxidant levels and in the frequency with which the NAAQS are exceeded.
The improvements are consistent with legally scheduled reductions of HC.
The maximum 1-hour nitrogen dioxide (NOg.) levels have generally
remained unchanged with some random fluctuations. The fluctuations are due
to exhaust control systems for HC and CO emissions from 1966-70 model
automobiles. These controls increased NOx emissions and thus increased
ambient NOj,concentrations. Control of NOx emissions in California began
with the 1971 model year.
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The average of maximum 1-hour HC concentrations generally remained
constant from 1965 to 1973. Since the number of automobiles increased,
this constant average may be attributed to control of HC emissions from
automobiles. Control of crankcase emissions began in California in 1963,
and exhaust control began with the 1966 model year.
Carbon monoxide. According to data from the NADB, the percentage
of values in Los Angeles above the 8-hour CO standard declined from 14
percent in 1970 to 6 percent in 1973 (Table IV-6). During the same period,
the San Francisco Bay Area sites showed less than 0.5 percent violations
of the 8-hour CO standard. With respect to the annual second highest 1-hour
average CO concentrations, both groups of sites made progress. In particular,
Los Angeles sites, which have historically produced some of the highest
1-hour CO concentrations, have steadily declined from a composite level
of 32 milligrams per cubic meter (mg/m ) in 1970 to 26 mg/m in 1973.
TABLE IV-6. CARBON MONOXIDE POLLUTION IN LOS ANGELES
AND SAN FRANCISCO, 1970-1973
Average second highest
annual 1-hour CO con-
centration, mg/m3
Average percentage
above 8-hour NAAQS
CO standard I/
Number
Area of sites
Los Angeles 10
San Francisco 7
Bay Area
1970 1971 1972 1973 1970 1971 1972 1973
32 32 31 26 14 11 8
15 16 16 14 2/ 2/ 2/
3
6
^
_!/ Ten milligrams per cubic meter (mg/m ).
_2_/ Less than 0.5 percent.
Source: National Air Data Bank.
b. Philadelphia
Total oxidants. Total oxidants show a downward trend in Philadelphia
from 1968 through 1972, followed by an increase from 1972 through 1974
(Figure IV-2). The downward trend may be accounted for by the emissions
controls systems on new cars and Philadelphia's Air Management Regulation
V for controlling stationary sources of organic emissions, which reduced
the amount of reactive hydrocarbons emitted into the air. The significant
rise in oxidants since 1972 may be the result of the increased automotive
NOx emissions which could be counteracting the HC reductions. 5/ Another
explanation could be adverse meteorology. An EPA study6_/ reported high
ozone levels in rural areas of Ohio and Pennsylvania due to adverse
meteorology in 1973.
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Nitrogen dioxide. Nitrogen dioxide levels increased in Philadelphia from.
1972 through 1974 (Figure IV-2), possibly reflecting a temporary increase in
emissions associated with the 1970-73 model cars, 5_/ Future cars should
emit less NO^ (one component of NOx) and so ambie~nt NOg, concentrations
should be lower.
Total hydrocarbons. Total hydrocarbons in Philadelphia show no signi-
ficant upward or downward trend (Figure IV-2). 5/ This is expected since
approximately 80 percent of the hydrocarbons are methane which is thought
not to represent an air pollution problem, and which also comes from decay
of natural organic materials. The nonmethane hydrocarbons, on the other hand,
are of concern because of their role in the formation of photochemical oxidants.
With the exception of the past 12 months, these hydrocarbons are exhibiting
a slight downward trend. The upward trend since then is difficult to
explain since total HC emissions have been reduced by emission controls on
new cars and vigorous enforcement of Philadelphia Regulation V.
Carbon monoxide. Carbon monoxide in Philadelphia does not show a
clea'r trend (Figure IV-2), in spite of controls on automobiles and emission
reductions achieved at stationary sources. 5/ The downward trend over
recent months is attributed primarily to recEuced use of automobiles during
the 1973-74 fuel shortage. This trend may also be beginning to reflect
emission controls on new cars,,
c. New Jersey, New York, and Washington_State
Carbon monoxide emissions declined in New Jersey, New York, and
Washington, according to NADB (Table IV-7). The downward trend in the
percentage of annual values above the 8-hour standard is noteworthy because
this is the CO standard that is most frequently violated. The decreasing
trend can be explained, in part, by the success of the Federal Motor Vehicle
Emissions Control Program. In contrast* there appears to be no progress
in reducing the annual second highest 1-hour average CO concentrations
for each of the States. The apparent discrepancy between the two measures
is not surprising. Short-term statistics such as the 1-hour maximum are
notoriously influenced by irregular conditions, such as high CO levels due
to extraordinary traffice tie-up. Consequently, the 1-hour maximum may
be an unreliable indicator of real change. However, because of its relation-
ship to the NAAQS, the 1-hour measure should not be totally ignored. Yet
the percentage of values above a particular threshold, such as the 8-hour
NAAQS, takes into consideration an entire year of data, averaging out a
variety of conditions and is, therefore, a more stable indicator.
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Figure IV-2. Total Oxidants, Nitrogen Dioxide, Total Hydrocarbons
and Carbon Monoxide Concentrations, Philadelphia
(29th and Race Streets)
NITROGEN DIOXIDE (NOa)
TOTAL OXIDAHTS
iL ITi'.OARO
TOTAL K
NON-METMANE HYDROCARBONS
CARBON MONOXIDE (CO)
Source: "Emissions Inventory and Air Quality Report to the Air
Pollution Control Board. " Air Management Service,
Philadelphia Department of Public Health, Philadelphia,
Pa., October 1974 (Revised).
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TABLE IV-7. CO POLLUTION IN SELECTED STATES,
1970-73
Average second highest Average percentage
annual 1-hour CO con- above 8-hour NAAQS
Number centration, mg/m3 CO standard I/
Area
New Jersey
New York
Washington
of sites
15
8
7
1970 1971
20 30
20
21
1972
28
16
20
1973
30
18
23
1970 1971
16 9
1
5
1972
10
1
4
1973
7
1
3
3
_L/ Standard is 10 milligrams per cubic meter (mg/m).
Source: National Air Data Bank.
2. Health Effects of Pollutants Generated by Mobile Sources.
National emissions standards for mobile sources were established in the
late 1960's primarily to protect public health. Standards for CO, HC and NO
emissions were established by statute at levels aimed toward achievement
of the NAAQS established by EPA in 1971. In accordance with 1970 Clean
Air Act Amendments, the air quality standards were established at levels
intended to assure protection of the health of certain susceptible segments
of our population, with an adequate margin of safety. This assumes that
susceptible persons should not experience aggravation of their preexisting
diseases due to environmental pollution. If ambient exposures are below
such effects levels, it is assumed that the otherwise healthy population will
be unaffected. In reality, however, air quality standards must also be based
on a consideration of the nature, increased frequency, and severity of
reversible health disorders, as well as the increased risk of future and more
irreversible diseases in otherwise healthy persons. Table IV-8 summarizes
the adverse health effects which appear to be related to mobile source
pollutants.
a. Methodology of Assessing Benefits
Assessment of public health benefits associated with automotive pollutant
control is a complex process involving the following steps:
Calculate changes in automotive pollutant emission factors.
Project the impact of emission factors on ambient levels or
calculate ambient pollutant trends.
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TABLE IV-8. ADVERSE HEALTH EFFECTS DUE TO EXPOSURE TO
NOx , CO, and OXIDANTS
Population-
Pollutant at-risk
Expected health effect
NOx
Those with pre-existing
disease
Aggravation of asthma
Aggravation of heart and lung disorders
Increased severity of acute respiratory disease
Otherwise healthy
Increased susceptibility to acute respiratory
disease
Diminished tolerance to exercise
Increased risk of chronic respiratory disease
Diminished lung function
Care ino genes is/mutagene sis (potential
hazard due to nitrate or nitrite exposure)
CO Pre-existing disease
Otherwise healthy
Oxidant Pre-existing disease
Otherwise healthy
Increased mortality among persons suffering
myocardial infarctions
Aggravation of heart disease
Increased risk of heart disease
Decreased mental activity
Tolerance to exercise diminished
Aggravation of asthma
Aggravation of chronic lung disease
Aggravation of heart disease
Decreased physical performance
Irritation of eyes and respiratory tract,
headache
Altered athletic performance
Increased susceptibility to acute
respiratory disease
Increased risk of chronic lung disease
Potential risk of mutagenesis/
care ino genie ity
Impaired fetal development
Decreased visual acuity
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Estimate what fraction of ambient pollution is attributable to
mobile sources.
Derive dose-response functions for adverse effects related to
automotive pollutants.
Estimate populations at risk.
Assess benefits by combining the data generated (synthesis).
This methodology will not necessarily furnish a quantitative assessment
due to the lack of sufficient data. The following discussion is, therefore,
a description of existing health benefits rather than a quantitative statement
of those benefits.
Changes in Emissions and Air Quality Factors
Changes in automotive emission factors for CO, HC, NOx can be readily
calculated. (See Section IV-6-1). Unfortunately, such changes cannot
be simply or quantitatively related to ambient air quality trend data. This
is due to a number of factors, not the least of which is the location where
a pollutant is sampled and the difficulty in relating localized pollutant
sources to the area-wide pollutant burden. The general air pollutant trends
for automotive related pollutants were presented in the previous section on
Air Quality Improvement.
Assessment of Mobile Source Contribution
Normally the fraction of ambient exposures due to automotive pollutants
is estimated by calculating the pollutant contribution from all sources within
an Air Quality Control Region based upon emission factors and number of
sources. While this approach gives a general picture of the contribution of
source emissions to the area-wide pollutant burden, it does not provide
information related to site-specific exposures to pollutants from various
sources, for example, CO exposure from mobile sources on a crowded
freeway. Such exposures are also linked to human activity patterns in
the urban-suburban area.
It is possible that greater public health benefits are being achieved
from mobile source control of CO, which causes direct adverse health
effects, than is evident from air quality data. Recent studies by Stewart
et al, regarding reduced blood carboxyhemoglobin levels in Chicago
blood donors from 1970-1975 lend support to this possibility. 8_/
In attempting to assess the difficult question of mobile source
contribution, the NAS estimated that approximately 1 percent of the total
urban health hazard was from air pollutants. The ranges of estimates
discussed was from 0.1 to 10 percent. The report further attributed
the health hazard associated with automotive-generated pollutants at
from 10 to 25 percent of the present air pollution related risk.
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Dose Response Functions
.Estimating dose-response for specific pollutant exposures
.c an extremely difficult task. While this has been attemptedlO/ such
functions must be viewed as preliminary at this time due to a number of
difficulties:
ซ Does-response functions assume no adverse health effects
below the NAAQS--that is the NAAQS is assumed to be a
"no-effect" exposure level.
ff Not enough is known about the magnitude and frequency
of exposure to environmental pollutants, thus making
the translation of environmental monitoring into human
exposure models a very complex undertaking.
ฎ Health effects studies are very limited.
ฉ There is usually no research base linking clinical,
occupational epidemiological, and toxicological
studies.
Pi-y;.lation-at-Risk
In estimating the population-at-risk, it is necessary to examine
both the relationship of populations to ambient pollution and the segment
of those populations of concern from a public health viewpoint. The
general population distribution can be determined from the 1970
Census (Table IV-9).
TABLE IV-9. U. S. POPULATION DISTRIBUTION BASED
ON 1970 CENSUS
Location
Total
Rural
Urban
Urban
in metropolitan
11
Population
203,211,926
53,886,996
149,324,930
52,182,000
areas over 2, 000, 000
in population
J7 County and City Data Bank Book, U. S.
Department of Commerce, 1972.
.'ming that the air pollution problem related to the automobile
is principally focused in urban centers exceeding 2 million in population,
then 52 million people are susceptible to adverse health effects from such
pollutants. 10/ The number of these people who experience aggravation
of existing dTseases can be approximated using baseline estimates for
adverse health effcts (Table IV-10).
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-39-
Reasonable predictions of premature death of increased mortality
from mobile source-generated pollutants are possible only for CO.
One estimate_2_/ suggests that the population-at-risk from increased
mortality due to CO exposure in cities larger than 100, 000 in population
is 70,000. One can assume that about 75 percent of the CO exposure
in such cities is related to mobile sources.
TABLE IV-10. ESTIMATED POPULATION-AT-RISK FROM CO AND
OXIDANT AIR POLLUTANTS, WITH PRE-EXISTING
DISEASES IN METROPOLITAN AREAS OVER 2
MILLION IN POPULATION_!/
Adverse Health Population Segment Estimated Population-
Effect Experiencing Effects at-Risk
Chronic Heart and 27% of those over 1, 231, 000
Lung Disease at 65
Asthma 3% of general 1,560,000
population
Excess acute lower 6% of all children 731,000
respiratory disease through age 13
Chronic bronchitis 2% in nonsmokers, 2,335,000
symptoms 10% for smokers
TOTAL 5,757,000
I/ From County and City Data Book, U. S. Department
~ of Commerce, 1972.
These 5. 7 million already susceptible persons constitute approximately
2. 5 percent of the U. S. population and are located in regions where
automotive-related pollutants contribute a greater percentage of the total
pollutant burden than in rural or less urbanized areas.
EPA is currently working to develop better estimates of population
exposure to support its health effects research and air pollution control
programs. These estimates will be based on actual ambient
concentrations as opposed to the crude population density basis used
above.
Synthesis
Though the methodology presented above for assessing public health
benefits is valid, it is not possible, with existing health effects data, to
state quantitatively the public health benefits derived from control of
mobile source emissions. The inability to make such an assessment
should not be interpreted to mean that no benefits are resulting from
emission control. Table IV-8, above, summarizes the available
information which suggests that mobile source generated pollutants
are related to definite adverse health effects in both the susceptible
and otherwise health segments of the population. It is logical to assume
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-40-
that by reducing the ambient levels of pollutants causing adverse health
effects the risk of the adverse effects themselves is decreased.
Therefore, while a quantitative assessment cannot be made, it is
possible to provide a qualitative assessment based on the air quality
data presented earlier. When ongoing health effects research is
completed, it is hoped that a more quantitative specific assessment
will be available.
b. Qualitative Assessment of Health Benefits
The analysis of oxidant, HC,~ NO , and CO trends have been
discussed in the previous section. "Air Quality Improvement. " As
noted therein, the data base is insufficient to examine national and
regional trends, thus a few major cities are examined. Carbon
monoxide, which is principally derived from mobile sources, appears
to be decreasing, although no clear trend is obvious in some areas
(Philadelphia). One would expect decreased localized exposures to
automotive-generated CO also, due to the significant reduction in CO
emissions from our current vehicle fleet. Thus, as suggested by
Stewart, the population may be experiencing definite health benefits
from decreased CO exposures.
Oxidant. appears to be decreasing in Los Angeles, San Diego, San
Francisco, and Sacramento, but has increased since 1972 in Philadelphia.
These changes are too small, however, to permit a statement of whether
specific health benefits have or have not been achieved. If the generally
decreasing trend noted in California continues it can be assumed that the
risk of oxidant related diseases will decrease.
Nitrogen dioxide trends suggest that levels are increasing in some
areas'!One can conclude, that, to a limited degree, public health risks
are increasing. Assessment of such risks is, however, extremely
difficult because the NAAQS is an annual standard. A short term NOx
standard, based upon health criteria, would permit a better assessment
of public health related to both area-wide and localized exposure to NOx.
The standard cannot be established, however, until further research is
completed on health effects.
It is also likely that health benefits are resulting from decreased
emissions of polynuclear aromatic hydrocarbons and certain other
nonregulated organic pollutants. The control of these pollutants has
indirectly resulted from control of HC and CO emissions.
In summary, mobile source control of CO is believed to be providing
a net public health benefit. Assessing the public health benefits of HC
and NOx control is more difficult because of the complex atmospheric
interactions which cause HC and NOx to form oxidant. Such an assessment
is also difficult because of the absence of a short-term health basis for
assessing NOx effects. In general, oxidant appears to be decreasing
while NOx is increasing. While the available data does not permit a
quantitative assessment of derived health benefits, it does suggest
strongly that where ambient levels of pollutants have been decreased,
public health benefits in terms of reduced risk to pollutant related diseases
have occurred.
-------
FOOTNOTES
1. Gumbelton, James J., et al. Optimizing Engine Parameters
with Exhaust Gas Recirculation. " Society of Automotive
Engineers, Paper No. 740104, New York, New York, 1974.
2. "The National Air Monitoring Program: Air Quality and
Emissions Trends Annual Report." U. S. Environmental
Protection Agency, Research Triangle Park, N.C.
Publication No. EPA-450/l-73-001a. 1973.
3. "Monitoring and Air Quality Trends Report, 1972," U. S.
Environmental Protection Agency, Research Triangle
Park, N. C. Publication No. EPA-450/1-73-004.
December 1973.
4. Simeroth, D., and D. Koberlein. "Air Quality in the San Diego
Basin. " California Air Resources Board, Division of
Technical Services, Sacramento, Cal., August 1974.
5. "Emissions Inventory and Air Quality Data Report to the Air
Pollution Control Board." Air Management Services,
Philadelphia Department of Public Health, Philadelphia, Pa.
October 1974 (Revised).
6. "Investigation of Rural Oxidant Levels as Related to Urban
Hydrocarbon Control Strategies. " U. S. Environmental
Protection Agency, Research Triangle Park, N. C.
Publication No. EPA-450/3-75-036. March 1975.
7. "Monitoring and Air Quality Trends Report, 1973." U. S.
Environmental Protection Agency, Research Triangle
Park, N. C. Publication No. EPA-450/1/-74-007.
October 1974.
8. Stewart, R. D., et al. "Carboxyhemoglobin Trend in Chicago
Blood Donors, 1970-1975. " EPA Scientific Seminar on
Automotive Pollutants, Washington, D. C. February 10, 1975.
9. "Air Quality and Automotive Emission Control. " A Report by
the National Academy of Sciences to the Committee on Public
Works, United States Senate, September 1974.
10. Finklea, John, et al. "Estimates of the Public Health Benefits
and Risks Attributable to Equipping Light Duty Motor Vehicles
With Oxidation Catalysts. "
11. "Impact of Using Oxidation Catalysts on Light Duty Motor Vehicles
on Human Exposures to Regulated and Non-Regulated Emission
Products." U. S. Environmental Protection Agency, Research
Triangle Park, N. C.
MJ.S. GOVERNMENT PRINTING OFFICE: 1976 624-542/655
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