EPA 310, 9-78-055A
United States
Environmental Protection
Agency
Reaion 10
1200 Sixth Avenue
Seattle WA 98101
Air
December 1978
Part 1
Carbon Monoxide Study
Boise, Idaho
November 25 -
December 22, 1977
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EPA 910/9-78-055a
Part 1. CARBON MONOXIDE STUDY - BOISE, IDAHO
NOVEMBER 25 - DECEMBER 22, 1977
EXECUTIVE SUMMARY
PREPARED BY
C. B. Wilson and J.W. Schweiss
SURVEILLANCE AND ANALYSIS DIVISION
FOR
AIR PROGRAMS BRANCH
AIR AND HAZARDOUS MATERIALS DIVISION
U.S. ENVIRONMENTAL PROTECTION AGENCY, REGION 10
1200 SIXTH AVENUE
SEATTLE, WASHINGTON 98101
DECEMBER 1978
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DISCLAIMER
This report has been reviewed by the Environmental Protection Agency
Region 10 and is approved for publication. Approval does not signify that
the contents necessarily reflect the views and policies of the Environmental
Protection Agency nor does mention of trade names or commercial products
constitute endorsement or recommendation for use.
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PREFACE
Under the Clean Air Act of 1970 the U.S. Environme ital Protection Agency
has established standards for carbon monoxide in air external to buildings
to which the public has access. In a number of cities, including Boise,
these standards have not yet been attained. Plans to achieve the standards
are now required under the Clean Air Act Amendments of 1977 (PL 95-95).
It is hoped that the material presented in this report will assist in
achieving progress towards attainment of the standards.
iii
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ACKNOWLEDGMENTS
We gratefully acknowledge the assistance of many members of the Idaho State
Department of Health and Welfare, the Idaho Transportation Department, and
Ada Planning Association in providing information for the planning and con-
duct of this study. We especially wish to thank the Idaho State Department
of Health and Welfare for providing facilities to establish a field labora-
tory in Boise for use by the EPA contractor. A number of individuals gave
freely of their time and information and their efforts contributed materially
to this study, though they are not, of course, responsible for any errors
herein. These people include: Richard Johnson and Doss Terrel (IDHW), John
Hamrick, Keith Longnecker, and Lee Hatch (ITD); Ervin Olen, Jr. and Robert
Winter, Jr. (APA).
Several firms and institutions graciously permitted installation of equipment
on their premises and without their cooperation, portions of this study
could not have been conducted. Our sincere thanks go to: St. Luke's Hospi-
tal, Idan-Ha Hotel, Sexty1s Jewelers, David's Fabrics, Singer's, Falk's, and
Boise State University.
Finally, we express gratitude to many members of the EPA staff for guidance,
encouragement, and assistance.
IV
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TABLE OF CONTENTS
Page
Preface ill
Acknowledgments iv
Table of Contents v
List of Figures vi
List of Tables vii
Abbreviations and Symbols viii
INTRODUCTION 1
SUMMARY 1
CONCLUSIONS AND RECOMMENDATIONS 3
METHOD OF STUDY 7
RESULTS AND DISCUSSION 8
Outdoor Sites 8
Indoor Sites 26
Pedestrian Routes 26
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LIST OF FIGURES
Figure
1 Sampling Locations ....................... 9
2 Time Distribution of Eight-Hour Averages Over 9.0 ppm
During November-December for 1975, 1976, and 1977 ........ 12
3 Characteristics of Weekday Carbon Monoxide Average
Concentrations for an 8-Hour Period at Each Site ........ 16
4 Maximum 8-Hour Values for Entire Sampling Interval ....... 18
5 Frequency of 8-Hour Values Greater than 9.0 PPM ......... 19
6 Second-Highest 8-Hour Values for Entire. Sampling Interval. ... 21
7 Day of Highest Average Over All Sites ............. 23
8 Characteristics by Day of the Composite Range of Carbon
Monoxide Concentrations for All Sites During an 8-Hour Period. . 24
VI
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LIST OF TABLES
Table Page
1 Boise Carbon Monoxide Sampling Sites 10
2 Maximum Values from Forty Sites and the Permanent Monitor 11*
3 Comparison of Maximum Study Site and Permanent Monitor
Eight Hour Averages 25
vii
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Abbreviations and Symbols
AM - The four-hour* interval from 10:00 a.m.* to 2:00 p.m.*
PM - The four-hour* interval from 2:00 p.m.* to 6:00 p.m.*
AVC - The eight-hour* average CO concentration for the 10:00 a.m.* to
6:00 p.m.* sample collected at an EPA special study site (average
calculated from AM and PM concentrations)
AVS - The eight-hour average from 10:00 a.m. to 6:00 p.m. of continuous
non-dispersive infra-red measurements at the permanent monitor
ODD - The permanent monitor operated by the State at the Odd Fellows Hall
at 115J Ninth Street
n/o - north of as in "Ninth n/o Idaho"
w/o - west of as in "Idaho w/o Eighth"
Exceedence of Standard** - An eight-hour average CO concentration exceeding
9.0 ppm
Violation of Standard - The second eight-hour, non-overlapping, running
average in a year to exceed 9.0 ppm
* plus or minus fifteen minutes
** This report discusses only the standard for the eight-hour average and
does not discuss the standard for one-hour average CO concentrations.
viii
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INTRODUCTION
Frequent violations of the national ambient air quality standard* for
carbon monoxide (CO) have occurred at the only continuous monitor in down-
town Boise which is operated at 115J Ninth Street by the Idaho Department of
Health and Welfare (Figure 1). However, more information on the severity of
the CO problem and its geographical extent was desired to assist in selec-
tion of candidate sites for additional routine monitoring and to examine the
representativeness of the existing site. The levels of CO encountered by
pedestrians in the city and indoor occupants were also of interest. There-
fore, a study was planned and conducted to address these needs. This report
(Part 1) presents the major results and conclusions. A more detailed de-
scription of the methods, additional discussion and analysis and the data
obtained in this study appear in a separate volume (Part 2).
SUMMARY
In 1977, a 20-day study involving forty outdoor sites, six indoor sites, and
two pedestrian walking routes was conducted in Boise, Idaho during
* Federal Register, 42 FR8186, April 30, 1971. The standard for carbon
monoxide addresses two averaging periods. Eight-hour average CO concen-
trations shall not exceed 9 ppm more than once per year. One-hour average
CO concentrations shall not exceed 35 ppm more than once per year-
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November-December, the season when high carbon monoxide levels frequently
occur. The purpose of this study was to obtain additional data regarding
the magnitude and spatial extent of the carbon monoxide problem, the repre-
sentativeness of the only permanent monitor in the central business district,
and to assist in selection of candidate sites for routine monitoring. On
each week-day, four-hour bag samples were collected from about 10:00 a.m. to
2:00 p.m. (AM sample) and from about 2:00 p.m. to 6:00 p.m. (PM sample) at
33 of the outdoor sites and two of the indoor sites. In addition, bag sam-
ples of air were collected on two pedestrian walking routes over two to four
hours during the AM and PM periods.
Data are summarized in bar charts, which show the measurement distribution
for each site or for each day of the study period; in histogram-maps showing
the spatial distribution of carbon monoxide; and in tables. Results from
the study sites were compared in several ways with data from the permanent
monitor. Comparisons were also made between study sites along the same
corridor, between indoor sites and adjacent outdoor sites, and between the
two pedestrian routes. Eight-hour averages were compared with the 9.0 ppm
eight-hour standard.
The study results indicate that the carbon monoxide problem is widespread
and not restricted to the downtown commercial district. The magnitude of
the problem may be somewhat greater than shown by data from the permanent
monitor. The permanent monitor was generally representative of the higher
but not the highest concentrations. Even higher concentrations and more
frequent exceedences of the standard occurred on Idaho Street and Main
- 2 -
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Street as well as at a few other sites. Exceedences occurred at other loca-
tions and were more than 1.5 to 3 times greater than at the permanent monitor
when no exceedences were noted at the permanent monitor. Increases in carbon
i
monoxide at outdoor sites were frequently reflected by increases at indoor
sites. Pedestrians and some of the indoor population were exposed to concen-
trations above the standard.
Future monitoring should address the development of control strategies
(short-term) and then track progress towards achievement of the ambient air
quality standards (long-term). Planning for such studies should consider
the need for related data on traffic characteristics coupled with meteoro-
logical data.
CONCLUSIONS AND RECOMMENDATIONS
The major conclusions of a 20-day study conducted in Boise during about
10:00 a.m. to 6:00 p.m. on week-days of November-December 1977 are:
1. The magnitude of the carbon monoxide problem was somewhat greater than
indicated by the permanent monitor.
- For nine study sites, (1, 10A, 11, 13, 17, 18, 20, 24, and 32) the
maximum 10:00 a.m. to 6:00 p.m. eight-hour average exceeded the high-
est observed at the permanent monitor (13-7 ppm) during the study
period.
- 3 -
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- The highest eight-hour average (17.2 ppm) and most frequent exceed-
ences of the 9.0 ppm standard (70% of the study days) were observed at
site 32 on Idaho Street west of Eighth Street which most often had the
highest eight-hour average of all sites (9 of the 20 days).
2. The spatial extent of the problem encompasses not only the downtown
commercial district but also locations along traffic corridors outside
the core area.
- When higher concentrations were observed in the core area, elevated CO
levels also occurred elsewhere.
- Altogether about 70% of the study sites (28 out of 40) experienced one
or more days when the eight-hour average exceeded the 9.0 ppm eiqht-
hour standard. (A total of nineteen sites experienced two or more
days).
3. The permanent monitor was generally representative of the higher concen-
trations but did not represent the highest concentrations or frequency
of exceedences within the study area.
- On every day but one, the eight-hour concentration at the state
site was exceeded at one or more study sites.
- 4 -
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- During the survey, the second-highest eight-hour average for 10:00 a.m.
to 6:00 p.m. at the state site (10.8 ppm) was nearly equalled or ex-
ceeded at a total of fourteen sites including three in the same block.
At four sites (10A, 11, 17, and 32), concentrations were more than
2 ppm greater.
- On 95% of the study days (19 out of 20) the eight-hour standard was
exceeded at one or more sites. Exceedences at the state site occurred
on 47% (9 out of 19) of the sampled days.
- Eight-hour concentrations above the standard were observed at other
locations and were up to three times greater than at the permanent
monitor when no exceedence was noted at the permanent monitor.
. - When concentrations exceeded the standard at the permanent monitor
they were also exceeded at other locations.
4. Changes in CO concentrations at outdoor sites frequently coincided with
changes in CO concentrations at indoor sites, but the relationship be-
tween indoor and outdoor values was not constant.
- Concentrations were usually lower indoors than at the adjacent outdoor
site.
- Indoors, the eight-hour average concentration of carbon monoxide ex-
ceeded 9.0 ppm at times.
- 5 -
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5. Pedestrians were exposed to eight-hour average CO concentrations exceed-
ing the standard at times.
- For sampling periods between two to four hours, concentrations ranged
from 3.9 ppm to 14 ppm.
For nearly sequential sampling periods totalling seven or more hours,
averages were equal to or above 9.0 ppm on four days.
It is recommended that:
1. The carbon monoxide problem in Boise be considered a widespread problem.
2. Increased local source emissions be avoided in areas where violations
have been observed unless a reduction in the background concentrations
which is at least sufficient to offset the increase can be demonstrated.
3- Concentrations at the permanent monitor above 9.0 ppm be considered as
indicative of concentrations equally high and very likely higher else-
where in the study area. (Note that concentrations at the permanent
monitor below 9.0 ppm do not mean that air quality standards are being
met throughout the study area.)
4. A site on Idaho Street (site 32 or 10A) be considered as a candidate
site to represent carbon monoxide concentrations in downtown Boise for
- 6 -
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routine ambient air quality monitoring or for short-term monitoring
during the late fall and winter season, (November-December).
5. Planning for future studies to aid development of control strategies and
track progress towards attainment of the standard should consider the
need for related data on traffic and meteorological characteristics.
METHOD OF STUDY
Forty outdoor sites (Figure 1 and Table 1) were selected after a review of '
traffic characteristics, potential population exposure, and planning for the
Boise downtown area. Traffic volumes were a significant factor in the selec-
tion of many sites because the motor vehicle is by far the major source of
carbon monoxide in Boise. However, locations where high CO from idling
vehicles might occur in situations, such as entrances or exits from large
parking lots, were deliberately avoided. At each site, the sample inlet was
about 3J meters above the sidewalk, more than 10 meters from an intersection,
and more than 2 meters from a vertical wall. Most samples were a little
over one meter from the street curb; two were at much greater distances.
Each week-day, air was collected into a bag during two sequential periods
(about 10:00 a.m. to 2:00 p.m. and about 2:00 p.m. to 6:00 p.m.) so that an
eight-hour average could be calculated for comparison with the national
ambient air quality standard of 9.0 ppm which is not to be exceeded more
- 7 -
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than once per year. Samples were obtained during November 25 through Decem-
ber 22, 1977, on week-days from about 10:00 a.m. to 6:00 p.m. because this
period of the day seemed most likely to have high carbon monoxide levels
based on data from the permanent monitor (Figure 2). This appeared to be
true during the survey since the daily maximum eight-hour average at the
state site was within 1 ppm of the 10:00 a.m. to 6:00 p.m. average on all
but four days of the study. Carbon monoxide in the study samples was ana-
lyzed by an electrochemical oxidation method. Continuous analysis of air at
the indoor sites (in addition to bag sampling indoors and at the adjacent
outdoor site) monitored the daily pattern of indoor carbon monoxide levels.
Indoor sites representing exposure situations in downtown buildings within a
few blocks of the permanent monitor included three small retail shops, a
hotel, and a large department store. A hospital site about 0.8 mile east of
the permanent monitor was also sampled. At all locations, care was taken to
avoid non-vehicle sources of carbon monoxide such as tobacco smoke in the
immediate vicinity of the sampler or fuel combustion from building heating
systems. The nearest adjacent outdoor site was the basis for comparison.
RESULTS AND DISCUSSION
Outdoor Sites
The relative severity of the carbon monoxide problem at various outdoor
sites during the selected time period is indicated by several measures.
Maximum and second-highest eight-hour averages, the frequency of exceedences
observed at each site and maximum four-hour AM (10:00 a.m. to 2:00 p.m.) and
- 8 -
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FIGURE 1
Boise Carbon Monoxide Study
Location of EPA Sampling Sites
11725/77 to 12/22/77
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Table 1. BOISE CARBON MONOXIDE SAMPLING SITES
11/25 to 12/22, 1977
SITE NO.
1
2
3
4
5
6
7
8
9
11
12
13
14
15
16
17
18
19
20
21
22
MAIN STREET
Broadway
Broadway
Capitol
Capitol
Capitol
8TH
8TH
Main
9TH
9TH
State
9TH
Main
Main
10TH
Idaho
Main
11TH
Main
13TH
Front
CROSS STREET
n/o Myrtle
n/o Broad
n/o College
n/o Broad
n/o Idaho
n/o Idaho
n/o Main
w/o 8TH
n/o Main
n/o Idaho
w/o 8TH
n/o Main
w/o 9TH
w/o 9th
n/o Idaho
w/o 10th
w/o 10th
n/o Main
w/o 11th
n/o Idaho
w/o 15th
SIDE OF STREET
W
E
E
W
W
E
E
N
E
E
S
W
N
S
W
S
N
W
S
E
N
- 10 -
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Table 1 (cont'd). BOISE CARBON MONOXIDE SAMPLING SITES
11/25 to 12/22, 1977
SITE NO. MAIN STREET
CROSS STREET
SIDE OF STREET
23
24
25
26
32
10A
27A
27B
28A
28B
29A
29B
30A
30B
3U
31B
32B
33A
33B
Main
16TH
23RD
State
Idaho
Idaho
Capitol
13TH
Main
16TH
1ST
State
Capitol
State
Capital
15TH
16TH
9TH
Grove
w/o 15TH
n/o Main
n/o Fairview
w/o 22nd
w/o 8TH
w/o 8TH
n/o College*
n/o State
w/o Broadway
n/o State
n/o Idaho
w/o 18TH
n/o Myrtle
w/o 25TH
n/o Main
n/o Main
n/o River Road
n/o Main
w/o 11TH
S
W
E
N
N
S
W
E
N
E
W
S
E
S
W
W
W
W
N
* Actually n/o Sherwood
- 11 -
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Figure 2
Boise Carbon Monoxide
State Site* Data Summary
For the November - December
Periods in 1975, 1976 and 1977
Located til 115% N. 9th (Odd Fellows Building)
1975 Data
1976 Data
........ 1977 Data
Figure
Time Distribution of 8-Hour Averages Over 9.0 ppm
During November - December
(By Ending Hour)
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1000 1200 1400 1600 1800 2000
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ENDING HOUR
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PM (2:00 p.m. to 6:00 p.m.) averages in Table 2 may be compared with measured
values at the state site. Data distributions for each site's eight-hour
(10:00 a.m. to 6:00 p.m.) averages may be compared in Figure 3. Figures 4,
5, and 6 illustrate the spatial variation of the data in Table 2 on maps of
Boise.
In general, the lowest values occurred at site 3 on the Boise State Univer-
sity campus which was the farthest from any roadway (about 192 feet east of
Capitol Boulevard). The nearest roadway's contribution may have been rela-
tively less here and thus more indicative of the varying background level of
carbon monoxide.
Depending on the purpose of the analysis, different measures are appropriate
for examination of the representativeness of the existing permanent monitor.
Day-by-day similarities are not required to compare the necessary reduction
of carbon monoxide levels implied by data from two different sites. The
relationships between data at the state site and at other sites are not
necessarily the same from day-to-day. Because attainment of the national
ambient air quality standard will depend on developing and carrying out
plans to reduce existing CO levels, it is useful to know whether or not the
higher CO levels are similar at sites when measurements are taken over an
extended period. Therefore, the maximum eight-hour average concentration
and the frequency with which it exceeded the 9.0 ppm standard at each site
are appropriate measures for comparison.
- 13 -
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Table 2. Maximum Values from Forty Sites and the Permanent Monitor
Carbon Monoxide in ppm
Site
1
2
3
4
5
6
7
8
9
1 10 A*
| i
11
i
12
13
.14
15
16
17
18
19
20
21
22
23
Maximum AM
10 AM-2 PM
12.9
10.9
5.0
9.0
11.5
11.0
9.2
12.0
14.2
13.5
13.2
6.3
15.1
12.1
8.0
10.0
13.9
15.6
11.3
16.5
9.0
10.2
14.1
Maximum PM
2 PM-6 PM
16.5
8.9
4.5
10.0
15.5
11.0
12.8
16.0
13.3
20.6
18.0
12.9
15.2
11.5
7.5
14.0
16.5
14.9
13.1
13.5
11.2
12.0
11.8
Maximum AVC
10 AM-6 PM
14.7
9.0
4.8
9.5
13.5
10.5
8.4
13.0
13.6
15.9
15.6
9.5
14.2
11.2
7.6
9.9
15.2
15.3
12.1
13.8
9.9
11.1
13.0
% AVC1
GT 9.0
60
0
0
5
15
10
0
8
35
50
44
6
56
6
0
11
19
37
25
37
5
10
18
Ratio2
1.4
1.0
0.5
0.9
1.3
1.0
0.8
1.5
1.3
1.5
1.5
0.9
1.0
1.3
0.6
0.9
1.5
1.5
1.2
1.3
0.9
1.1
Date of
Maximum AVC
12/02
11/25
11/25
12/02
12/02
12/02
11/30
11/25
12/02
12/02
12/02
12/02
12/22
11/25
12/22
12/02
12/02
12/02
12/02
12/02
12/02
12/02
12/01
Second-Hi
AVC
12.6
7.7
4.2
6.9
11.8
9.4
8.1
9.0
11.9
13.2
13.3
8.6
12.4
7.9
7.5
9.4
13.6
12.1
10.2
11.5
8.4
9.1
11.6
Second
Ratio3
0.9
0,6
0.4
1.3
0.9
1.5
1.6
0.7
1.9
1.3
2.2
1.0
1.1
0.7
0.7
0.7
1.5
1.4
1.2
1.9
1.0
1.1
Date of
Second-Hi
12/22
12/22
12/02
12/12
12/22
12/06
12/12
12/22
12/06
12/05
12/06
1 1/25
12/19
12/02
11/30
12/22
11/25
11/25
11/25
12/06
12/01
11/25
12/02
-------
Site
24
25
26
27 A*
27B**
28A
28B
29A
29B
30 A
30B
31A
31B
32
32B
33A
33B
ODD***
Maximum AM
10 AM-2 PM
12.6
11.0
8.1
10.1
4.7
10.0
9.0
9.0
7.0
11.2
8.0
9.9
7.1
15.2
10.3
10.5
7.0
12.4
Maximum PM
2 PM-6 PM
17.5
15.8
14.0
10.1
6.5
9.9
9.3
9.9
4.5
12.0
5.7
10.5
6.5
19.9
9.1
13.3
10.1
15.1
Maximum AVC
10 AM-6 PM
15.1
13.4
10.6
10.1
5.3
8.0
7.8
9.5
5.4
11.4
6.0
8.7
6.3
17.2
9.7
11.6
8.4
13.7
Table 2. (con
% AVC1
GT 9.0 Ratio2
10
11
5
10
0
0
0
10
0
30
0
0
0
70
14
50
0
47
1.4
1.3
1.0
1.0
0.4
0.8
0.6
0.9
1.0
1.1
1.5
0.9
0.5
1.3
1.9
1.1
2.1
t)
Date of
Maximum AVC
12/02
12/02
12/02
12/02
12/22
12/02
12/22
12/02
12/12
12/02
12/14
11/28
12/22
12/22
12/12
11/30
12/14
12/22
Second-Hi
AVC
9.1
11.0
8.6
7.2
4.1
8.0
6.4
8.5
4,9
11.0
4.6
7.7
5.7
16.5
8.1
10.6
7.2
10.8
i
Second
Ratio3
1.5
1.8
1.0
1.2
0.4
0.8
1.6
1.4
0.4
1.2
0.9
0,7
1.1
1.6
0.6
1.1
1.7
Date of
Second-Hi
12/06
12/06
11/25
12/06
12/21
12/02
12/14
12/06
12/22
11/25
12/12
12/02
12/12
12/02
12/22
12/05
12/20
12/19
* "A" suffix indicates sampled first 10 days.
** "B" suffix indicates sampled last 10 days.
*** State's permanent monitor at Odd Fellows Hall, 115^ Ninth Street.
1 Frequency of AVC's exceeding 9 ppm, expressed as a percentage of the number of samples,
2 Ratio of maximum AVC to the eight-hour average for the same time at ..the State site,
3 Ratio of second-highest AVC to the eight-hour average for the same time at the St,ate site.
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Boise Carbon Monoxide
November 25 to December 22, 1977
(Weekdays Only)
Figure 3
Characteristics of Weekday Carbon Monoxide Average Concentrations for
an Eight-Hour Period (10:00 A.M. to 6:00 P.M.) at Each Site.
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Maximum
2nd highest
Mean + one standard deviation
Median
Mean
Mean - one standard deviation
Minimum
Standard not to be exceeded
more than once per year
Sites - first 10 days
* Sites - last 10 days
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21 22 23 24 25 26 27A' 27B" 28A- 28B** 29A* 29B' 30A* 30B* 31A« 31B** 32 32B** 33A' 33B** ODD
Permanent Monitor
/ t i / y *? / / / / / / / / / / / ?# / / /
* O r» in f* ~. e* r* **. ^ s.w.O O^1 i-vOsT*
SITE NUMBER
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Note: Number of successful samples varies from site to site
-------
10 Scale in PPM CO
FIGURE 4
CARBON MONOXIDE
CONCENTRATIONS
11/25/77 to 12/22/77
BOISE CENTRAL BUSINESS DISTRICT
MAXIMUM 8-HOUR1 VALUES FOR ENTIRE
SAMPLING INTERVAL
Q Denotes 20-Day Sites (11/25/77)
| Denotes First 10-Day Sites (11/25/77-12/8/77)
I Denotes Last 10-Day Sites (12/9/77 - 12/22/77)
I Black Denotes Values Greater than 9 PPM CO
AM TO 6 PM
-------
FIGURE 5
- 100 Scale %
CARBON MONOXIDE
CONCENTRATIONS
st. 11/25/77 to 12/22/77
BA^°C* BOISE CENTRAL BUSINESS DISTRICT
ST
FREQUENCY1 OF 8-HOUR2 VALUES GREATER
ST THAN 9.0 PPM
%
*
^
U Denotes 20-Day Sites (11/25/77 - 12/22/77)
I Denotes First 10-Day Sites (11/25/77-12/8/77)
I Denotes Last 10-Day Sites (12/9/77 - 12/22/77)
| Black Denotes Frequencies Greater than 25%
'ROUNDED TO NEAREST 5%
210 AM TO 6 PM
-------
On 95% of the study days, the eight-hour standard was exceeded at one or
more sites. Several of the study sites experienced at least one eight-hour
average for 10:00 a.m. to 6:00 p.m. that was higher than the highest observed
at the state site during the survey period (13.7 ppm). These included sites
1, 10A, 11, 13, 17, 18, 20, 2H, and 32 with the highest, 17.2 ppm, at site
32 on Idaho west of Eighth Street (Figures 3 and 4). Site 32, which is a
block from the permanent monitorr had the most frequent exceedences of the
9.0 ppm standard (70$ of the sampled days) and most often had the highest
8-hour average of all sites (on nine days of the 20-day sample period).
Figure 5 shows that about 70* of the sampling sites (28 out of HO) experi-
enced one or more days when the eight-hour average exceeded the 9.0 ppm
standard. The frequency of exceedences for several study sites was greater
than for the permanent monitor (47/8). With the exception of Site 1 on Broad-
way north of Myrtle, these sites were within a couple of blocks of the exist-
ing monitor.
Figure 6 shows the second-highest eight-hour average at each site. During
the study period, the maximum second-highest AVC recorded for any site,
16.5 ppm at site 32, exceeded the second-highest eight-hour average for
10:00 a.m. to 6:00 p.m. at the permanent monitor, 10.8 ppm. Nineteen sites
/
experienced at least two days with an eight-hour period averaging above the
standard. These were widespread through the study area and included sites
on Broadway north of Myrtle; several blocks between Idaho and Main (on 9th,
11th, and 16th); several blocks north of Idaho (on 8th, 9th, and 10th); both
- 20 -
-------
FIGURE 6
-10
Scale in PPM CO
CARBON MONOXIDE
CONCENTRATIONS
11725/77 to 12/22/77
BOISE CENTRAL BUSINESS DISTRICT
SECOND HIGHEST 8-HOUR1 VALUES FOR
ENTIRE SAMPLING INTERVAL
| Denotes 20-Day Sites (11/25/77 - 12/22/77)
I Denotes First 10-Day Sites (11/25/77-12/8/77)
| Denotes Last 10-Day Sites (12/9/77 - 12/22/77)
I Black Denotes Values Greater than 9 PPM CO
'10 AM TO 6 PM
-------
blocks sampled on Idaho (west of 8th and 10th); several blocks on Main (west
of 10th, 11th, and 15th); Front west of 15th; Capitol north of Myrtle and
Idaho; and 23rd north of Fairview. Undetected violations may have occurred
at other sites or with greater magnitude at these same sites during the days
of the study.
On the day of the highest composite average of eight-hour values from all
sites, December 2, most sites experienced their highest concentrations. The
10:00 a.m. to 6:00 p.m. average carbon monoxide concentration for each out-
door study site on this day (Figure 7) shows that high concentrations were
not restricted to a few sites, but were widespread with twenty-four of the
twenty-nine sampled sites experiencing concentrations above 9.0 ppm. Eleven
of the sites had eight-hour concentrations more than 20? higher than the
state site's (10.5 ppm). Fourteen sites had averages similar to the state
site (ratios greater than or equal to 0.8 but less than or equal to 1.2);
only four sites had appreciably lower averages (ratios less than 0.8).
On some days at one or more study sites, a concentration above 9.0 ppm and
up to twice the concentration at the permanent monitor was noted when con-
centrations at the permanent monitor were below the standard (Figure 8).
However, a concentration above 9.0 ppm at the permanent monitor was usually
accompanied by equally high or higher concentrations elsewhere. The concen-
tration at the permanent monitor was higher than at any other site on only
one day of the study (Table 3).
- 22 -
-------
r10
-0
Scale in PPM CO
* No monitoring data for these sites this date
FIGURE 7
CARBON MONOXIDE
CONCENTRATIONS
11/25/77 to 12/22/77
BOISE CENTRAL BUSINESS DISTRICT
DAY1 OF HIGHEST AVERAGE OVER ALL SITES
Denotes 20-Day Sites (11/25/77 - 12/22/77)
I Denotes First 10-Day Sites (11/25/77-12/8/77)
I Denotes Last 10-Day Sites (12/9/77 - 12/22/77)
Black Denotes Values Greater than 9 PPM CO
AM TO 6 PM
12/2/77
-------
FIGURE 8
Boise Carbon Monoxide
November 25 to December 22, 1977
Characteristics by Day of the Composite Range of Carbon Monoxide
Concentrations for all Sites During an Eight-Hour Period.
(10A.M. to 6 P.M.)
A
Maximum
Mean +. one standard deviation
Median
T
- Mean - one standard deviation
- Minimum
~l Permanent Monitor
20.0 T-
N>
15.0 - -
Op
||,0.0
oz
El
o
o
CO
5.0 - -
i
1
TT
W
I
T
o
T
T
r
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/ *'
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T
11/25 11/28 11/29 11/30 12/1 12/2 12/5 12/6 12/7 12/8 12/9 12/12 12/13 12/14 12/15 12/16 12/19 12/20 12/21 12/22
-------
Comparison of Maximum Study Site Each Day and Permanent Monitor
Eight-Hour Averages
(carbon monoxide in ppm)
STUDY SITES
Maximum
Study Site
32
32
1
33A
23
32
10A
11
32
13
32
1
11
11
32
32
13
20 and 11
32
32
Maximum
AVC»
16.2
11.3
11.0
11.6
13.0
16.5
13-2
13.3
8.7
9.4
12.1
11.1
9.8
11.9
9.9
11.0
12.4
10.1
12.6
17.2
Ratio
AVC/AVS«»
1.8
1.2
1.3
1.1
_
1.6
1.3
2.2
1.4
1.2
1.2
2.1
7.8
3.0
.9
1.8
1.1
2.4
1.2
1.3
PERMANENT MONITOR
AVS«»«
8.8
9.8
8.3
10.7
10.5
9.9
6.2
6.4
7.6
9.7
5.2
1.3
4.0
10.7
6.0
10.8
4.
10,
1
.2
Maximum
Eight-Hour
9.3
10.7
8.3
10.7
10.5
9.9
6.2
7.4
8.2
9.7
8.4
2.8
4.0
10.7
6.4
12.0
7,
10.
1
.5
13.7
13.7
End
Hour
1500
1600
1800
1800
1800
1900
1800
1500
2000
1800
1500
0100
1800
1800
1500
1900
1400
2000
1900
* Eight-hour average CO concentration for 10:00 a.m. - 6:00 p.m. (1000 -
1800) at a study site
** Ratio AVC/AVS - The ratio of the eight-hour average CO concentration at
the study site to that at the permanent monitor on the same day for the
10:00 a.m. - 6:00 p.m. period.
** Eight-hour average CO concentration for 10:00 a.m. - 6:00 p.m. at the
permanent monitor operated by the State at 115J Ninth Street.
- 25 -
-------
The study ended on Thursday, December 22, the day before the highest eight-hour
average for 1977 was recorded at the permanent monitor - 18.5 ppm ending at
6:00 p.m. Based on data collected during the study, it seems highly likely
that concentrations greater than this occurred at one or more study sites on
Friday, December 23.
Indoor Sites
At all six indoor sites, the concentrations were usually less than at the
adjacent outdoor sites. Otherwise, no consistent relationship between indoor
and outdoor levels was noted in this limited study. Nevertheless, the eight-
hour average concentrations on one or more days exceeded 9.0 ppm at four of
the indoor locations with maximum values ranging from 10.0 to 11.1 ppm. At
several sites, late afternoon increases in indoor CO were observed, suggesting
an influence from the afternoon peak traffic.
Pedestrian Data
Sampling periods ranged in length from about two to four hours on two routes
which varied from day to day. For these samples, concentrations ranged from
3.9 ppm to 14 ppm. On four days, the average of morning and afternoon samples
totalling about seven or more hours was equal to or above 9.0 ppm.
Correlations were examined between concentrations on Route A and those on
Route B and were surprisingly high. Better correlations were found between
the different routes on the same day than between morning and afternoon samples
from the same route.
- 26 -
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA 910/9-78-055a
3. RECIPIENT'S ACCESSIOWNO.
4. TITLE AND SUBTITLE
Carbon Monoxide Study - Boise, Idaho
Executive Summary
November 25 - December 22, 1977
5. REPORT DATE
December 1978
6. PERFORMING ORGANIZATION CODE
'. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
C. B. Wilson and J. W. Schweiss
9. PERFORMING ORGANIZATION NAME AND ADDRESS
U.S. Environmental Protection Agency
Region 10, Surveillance and Analysis Division
1200 Sixth Avenue
Seattle, Washington 98101
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
See also EPA 910/9-78-055b
16. ABSTRACT
This report is a summary of EPA 910/9-78-055b, a study of the carbon monoxide
problem in Boise.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
carbon monoxide
air quality data
air pollution sampling
Boise (Idaho)
13. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (This Report)
unclassified
21. NO. OF PAGES
35
20. SECURITY CLASS (This page)
unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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