&EPA
United States Office of Air Quality
Environmental Protection Planning and Standards EPA/453-F-99-002
Agency Research Triangle Park, NC 27711 July 1999
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Health Risks in Urban Areas
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Why is EPA concerned about air
toxics?
Millions of people live in areas where toxic air
pollutants can potentially pose serious health
concerns. Since 1970, the Clean Air Act has provided
the principal framework for protecting people and
the environment from the harmful effects of air
pollution. When Congress passed the Clean Air Act
Amendments in 1990, they directed the
Environmental Protection Agency (EPA) to address
toxic air pollutants coming from sources such as
chemical plants, steel mills, cars and trucks.
Progress has been made by EPA, state and local air
pollution agencies, and industry in reducing air
toxics, but more needs to be done. One component of
EPA's efforts focuses on toxic air pollutants in urban
areas. Toxic air pollutant emissions in and around
urban areas are usually caused by the heavy
concentration of factories, the large number of
vehicles and other commercial activities in these
areas. EPA has developed an urban strategy to target
air toxics emissions that potentially pose the greatest
health threat.
What are toxic air pollutants?
Under the 1990 Amendments to the Clean Air Act,
EPA is required to regulate sources emitting major
amounts of 188 toxic air pollutants. Toxic air
pollutants include heavy metals (like mercury and
lead), volatile chemicals (like benzene), combustion
byproducts (like dioxin), and solvents (like carbon
tetrachloride and methylene chloride). Exposure to
these pollutants under certain conditions causes a
wide range of potential human health and
environmental effects. For example,benzene is
known to cause cancer, while lead is known to cause
developmental delays.
Where do toxic air pollutants come
from?
There are literally millions of sources, ranging from
cars to industrial facilities, that emit toxic air
pollutants. Air toxics emissions come from mobile
Potential Effects
of Toxic Air Pollutants
Human Health
• Cancer
• Birth defects
• Developmental delays
• Reduced immunity
• Difficulty in breathing and respiratory damage
• Headache, dizziness, and nausea
Environmental
• Reproductive effects and developmental delays in
wildlife
• Toxicity to aquatic plants and animals
• Accumulation of pollutants in the food chain
sources, and large and small commercial and
industrial sources. Air toxics emissions occur
throughout the United States, but the highest
concentrations of sources occur primarily in urban
areas.
What has EPA done about air toxics
emissions so far?
As of June 1999, EPA has issued 43 air toxics
regulations for many of the larger industrial sources,
including chemical plants, steel mills, and lead
smelters, as well as some categories of smaller
commercial and industrial sources, like dry cleaners.
When fully implemented, these regulations will reduce
air toxics emissions by more than 1 million tons per
year.
Mobile sources can include cars, trucks,
buses, and non-road vehicles like ships or con-
struction equipment.
Small commercial and industrial sources
can include dry cleaners, gas stations, and
landfills.
Large commercial and industrial sources
can include chemical plants, oil refineries, and
steel mills.
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Other regulatory programs targeting mobile sources
and large and small commercial and industrial
sources have also indirectly helped reduce air toxics
emissions. For example:
• Controls to reduce volatile organic compounds
(VOC) emissions and small particle emissions
from all types of sources (both mobile and sta-
tionary) have resulted in reductions of air toxics
emissions.
• Eliminating leaded gasoline has resulted in a
sharp decline in airborne lead.
• Vehicles designed to meet the next generation of
emission standards ("Tier 2" emission levels) will
emit approximately 99% less VOC (many of
which are toxic pollutants).
What is EPA's Integrated Urban Air
Toxics Strategy?
EPA's Integrated Urban Air Toxics Strategy focuses on
reducing the human health threats of air toxics in
urban areas. Toxic air pollutants are of special
concern in urban areas because large concentrations
of people live and work near a variety of pollution
sources. In this Strategy, EPA outlines future actions
that it will take to reduce emissions of air toxics and
improve its understanding of the health threats posed
by air toxics in urban areas.
Goals
EPAs goals for the Strategy include reduction of
cancer and noncancer risks associated with air toxics
in urban areas (see Goals). In urban areas, air toxics
may threaten the health of some people more than
others, depending on factors such as where they live
in relation to toxic sources. EPA also has a specific
goal to prevent this type of unfair or disproportionate
exposure to air toxics.
Pollutants Posing the Greatest Health Threat
As a first step, EPA identified 33 of the 188 toxic air
pollutants posing the greatest threat to public health
in urban areas (see List). This list is based on the
quantity of pollutants released to the air, the harm (or
toxicity) caused by these pollutants, and the
estimated concentration in the air.
Goals of the Integrated
Urban Air Toxics Strategy
Reduce by 75% the risk of cancer associated
with air toxics from both large and small commer-
cial and industrial sources.
Substantially reduce noncancer health risks (e.g. birth
defects and reproductive effects) associated with
air toxics from small commercial and industrial
sources.
Address and prevent disproportionate impacts of air
toxics hazards, such as those in areas known as "hot
spots," and on sensitive populations in urban areas,
including: children, the elderly, minority and low-income
communities.
Although diesel emissions are not included as a
specific pollutant in this list, many of the hazardous
constituents of diesel emissions are included among
the 33 urban air toxics. EPA will address diesel
emissions specifically as part of an upcoming
regulation addressing air toxics emitted from mobile
sources. In addition, within the next year, EPA
expects to propose a rule lowering sulfur in diesel
fuel, which will significantly reduce levels of diesel
emissions.
List of 33 Urban Air Toxics
•acetaldehyde
•acrolein
•acrylonitrile
•arsenic compounds
• benzene
•beryllium compounds
•1,3-butadiene
•cadmium compounds
•carbon tetrachloride
•chloroform
•chromium compounds
•coke oven emissions
•dioxin
• 1,2-dibromoethane
• propylene dichloride
• 1,3-dichloropropene
•ethylene dichloride
•ethylene oxide
• formaldehyde
• hexachloro benzene
• hydrazine
•lead compounds
• manganese compounds
•mercury compounds
• methylene chloride
•nickel compounds
• polychlorinated biphenyls
(PCBs)
•polycyclic organic matter
(POM)
•quinoline
• 1,1,2,2-tetrachloroethane
• perchloroethylene
•trichloroethylene
•vinyl chloride
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Although these 33 air toxics are estimated to represent
approximately 20 percent of national air toxics emissions, they
are believed to be the most important air toxics contributing to
potential health risks in urban areas. Distribution of the
emissions of the 33 urban air toxics among the various source
types is shown below.
Large
Commercial
and
Industrial
Sources
20%
Small
Commercial
and Industrial
Sources
40%
Distribution of 33 Urban Air Toxics Emissions
(represents 1990 baseline)
How will EPA reduce urban air toxics and
address risk?
EPA's Strategy outlines the following steps that EPA will take to
reduce urban air toxics and address risk:
Achieve reductions through regulatory actions and related
projects. As one of the first steps in implementing the
Strategy, EPA will focus on reducing emissions from several
smaller commercial and industrial operations (referred to as
"area" source categories). Collectively, these types of sources
can emit large quantities of toxics in urban areas. By 2004,
EPA plans to complete regulations to address 13 such sources
(see Categories). These are in addition to 16 area source
categories for which regulation development is completed or
ongoing. EPA will also add to the list of categories in the future
as information about air toxics improves.
EPA will also continue to address emissions from all sources.
This includes an evaluation of the remaining health and
environmental risks from sources subject to existing air toxics
New Area Source Categories
• Cyclic Crude and Intermediate
Production
• Municipal Landfills
• Flexible Polyurethane Foam Fabrication
Operations
• Oil and Natural Gas Production
• Hospital Sterilizers
• Paint Stripping Operations
• Industrial Inorganic Chemical
Manufacturing
• Plastic Materials and Resins
Manufacturing
• Industrial Organic Chemical
Manufacturing
• Publicly Owned Treatment Works
• Mercury Cell Chlor-Alkali Plants
• Synthetic Rubber Manufacturing
• Gasoline Distribution (Stage I)
standards to
determine if
further controls are
needed. For
mobile sources,
EPA intends to
propose additional
regulations
addressing toxic
emissions from
motor vehicles and
fuels. EPA will
continue efforts
that target specific
pollutants (e.g.,
mercury) and
expects to initiate a number of pilot projects in the year 2000 to
identify and address specific community risks.
Collaborate with interested groups. EPA intends to work with
state, local, and tribal agencies, environmental groups,
environmental justice communities, and affected industries,
including small businesses, to assure that any actions under the
Strategy are responsive to health concerns while promoting
fairness, encouraging urban redevelopment, and minimizing
regulatory burden.
Expand knowledge about air toxics emissions and risks.
EPA recognizes that people want additional information about
air toxics in their community and the potential risk from these
emissions. In addition, EPA and state and local air agencies
would like this type of information to identify areas of concern,
set priorities, communicate risks to communities, and track
progress in reducing risks. EPA plans to do several assessments
of available air toxics emissions information that will be refined
over time as better information becomes available. The
information EPA provides to everyone will not only include
facts about exposure to air toxics, but also information on the
link between water quality and the deposition of air toxics.
As information about risks from air toxics emissions in urban
areas continues to improve, EPA will update the Integrated
Urban Air Toxics Strategy.
Where can I get more information on urban air toxics?
Visit EPA's Website at www.epa.gov/ttn/uatw/urban/urbanpg.html
or call the U.S. EPA Office of Air Quality Planning and Standards at (919) 5414487
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