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Journal of the Air Pollution Control Association Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/uawm16
The Need for Representative Ambient Air Carbon Monoxide Sampling a
Timothy M. Gilmore & Thomas R. Hanna
a
a
Alaska Department of Environmental Conservation Published online: 13 Mar 2012.
To cite this article: Timothy M. Gilmore & Thomas R. Hanna (1976) The Need for Representative Ambient Air Carbon Monoxide Sampling, Journal of the Air Pollution Control Association, 26:10, 965-967, DOI: 10.1080/00022470.1976.10470345 To link to this article: http://dx.doi.org/10.1080/00022470.1976.10470345
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
The Need for Representative Ambient Air Carbon Monoxide Sampling
Timothy M. Gilmore and Thomas R. Hanna Downloaded by [University of Western Ontario] at 21:47 10 November 2014
Alaska Department of Environmental Conservation
Recent investigations have indicated that ambient air CO measurements may not reflect population exposure to CO. The lack of correlation may be due to improper siting of CO instruments, improper interpretation of air quality data, or both. Studies of population carboxyhemoglobin levels are evaluated and compared with ambient air data., No significant correlation was found between median population COHb levels and reductions in CO concentrations required to meet ambient air standards when calculations used to estimate reductions were based on the second highest 8 hour average. However, calculated reductions based on annual average concentrations and a trend analysis technique correlated significantly with COHb levels in five cities from which both CAMP and COHb data were available. Studies to determine the nature of the relationship between ambient air CO concentrations and population COHb levels are needed. The differences between the Occupational Safety and Health Act Regulations and the National Ambient Air Standards for carbon monoxide should be scrutinized to determine if a redefinition of the standards or their applicability is warranted. A reevaluation of the controls necessary to make reductions in population COHb burden may be necessary.
Since air quality planning and subsequent control strategy implementation involve a considerable economic cost, it is paramount that data upon which plans are formulated be both representative and accurate. The following paper contains a discussion of ambient air CO data interpretation. The document entitled Air Quality Criteria for Carbon Monoxide was published by the National Air Pollution Control Administration in 1970 to provide a background for the subsequent CO Air Quality Standards. 1 These standards were based on findings noted in the criteria document that demonstrable deleterious effects occur when the carboxyhemoglobin (COHb) level of a person exceeds 2%. This COHb level can be reached through an exposure to October 1976
Volume 26, No. 10
approximately 9 ppm of CO in air for 8 hr, which is the promulgated standard. However, there is current evidence that ambient air measurements may not reflect the COHb levels of the population. As the National Academy of Sciences recently concluded: "There is evidence that the monitoring systems currently used may not reflect human carbon monoxide exposure in the general population, and a reevaluation of standardization and operating techniques, as well as location of monitoring stations, is desirable." 2 Interpretation of Ambient Air CO Data
If the CO monitoring locations are representative of population exposure, then one should expect to find some
correlation between the population carboxyhemoglobin levels and the ambient air CO measurements. Recent investigations have revealed conflicting results, however. A study conducted in Seattle concluded that: "Exposure to ambient air in the CBD (Central Business District) can cause significant increases in the carboxyhemoglobin levels of non-smokers." 3 But a study conducted in St. Louis concluded that: "The data analyzed do not indicate a consistent relationship between ambient CO and COHb as would be expected... The increase in COHb levels for non-smokers (as a result of exposure to ambient CO) is quite small." 4 The average COHb levels in several cities in the U. S. described in another study exhibit no correlation with the 965
Downloaded by [University of Western Ontario] at 21:47 10 November 2014
calculated "rollback" of CO concentrations reportedly needed to meet the ambient air CO standards, as shown in Table I and Table II.5 The "rollback" method is based upon the maximum measured outdoor CO concentrations. The poor statistical correlation suggests that the use of maximum measured ambient, or outdoor, concentrations of CO may be an inadequate measure of population COHb concentrations. Another investigation has indicated a great deal of uncertainty in projecting reductions in CO concentrations needed to meet the air quality standards.6 However, calculations of required pollutant reductions in 5 cities based upon annual mean CO concentrations rather than the second highest 8 hr average measurement resulted in a good correlation between the calculated necessary reduction and the median COHb levels in the population, as shown in Tables I and II. Use of annual averages rather than highest measured values may be more meaningful for evaluating population exposures to CO because missing data, instrument malfunctions and possible anomalous occurrences would not tend to be as significant in an annual average. The statistical correlation between population COHb and annual average CO concentrations in 13 cities was not significant, however, as shown in Tables I and II. The use of annual mean CO concentrations was proposed in a paper presented by Pierrard, Snee and Zelson, in which they demonstrated a consistent relationship between the standard deviation of 8 hr averages and the annual
Table II. Correlation between median COHb level and calculated necessary ambient CO concentration reductions for U.S. cities listed in Table I. 1) Calculated reduction from 1972—73 Federal Transportation Control Plans, based on 2nd highest eight hour average CO concentrations. Correlation Coefficient . . .r = —0.116 Number of Data Pairs . . . . n = 13 "t" Test on r t = -0.387 The correlation between the measured COHb and CO concentrations in the thirteen cities is not significantly different from zero 2) Calculated reduction from the 1971 annual average CO concentrations from CAMP sites. Correlation Coefficient. . . r = 0.937 Number of Data Pairs . . . . n = 5 " t " Test on r t = 4.66 Both CAMP and COHb data were available from only five cities. The correlation between measured COHb levels and calculated CO concentration reductions is significant at the 98% confidence level. 3) Calculated reduction from the 1972 annual average CO concentrations from the 13 cities. Correlation Coefficient. . . r = 0.230 Number of Data Pairs . . . . n = 13 "t" Test on r t = 0.786 The correlation between measured COHb levels and calculated CO concentration reductions is not significant. If only the five cities from which CAMP data were available are considered, however, the correlation is significant at the 90% confidence level with a correlation coefficient at 0.87.
mean value of data from several cities using CAMP data.7 This may indicate that a different technique should be considered as the basis for evaluating CO data. The data considered were taken only from CAMP stations for which several years data were available. The correlation may indicate that data from uniformly selected sites may be useful indicators of population COHb. However, it must be noted that the CAMP stations were designed to be representative of a portion of the business district in each city and not for documentation of long term changes in pollution levels.2'8
Table I. Median COHb concentration and calculated reductions necessary to meet ambient air CO standards in some U.S. cities.a
City Anchorage Chicago Denver Detroit Los Angeles New Orleans New York Phoenix St. Louis Salt Lake City San Francisco Seattle Washington, DC a
Median nonsmoker COHb concentration5 (%) 1.5 1.7 2.0 1.6 1.8 1.6 1.2 1.2 1.4
1.2 1.5 1.5 1.2
Calculated necessary reductions From 2nd highest eight hour average, 1972-73 Federal TCP data (%)
From the From the annual average annual average 1971 CAMP 1972 SAROAD data b (%) data b (%)
25'° 50" 64'" 0" 79' 3 0" 72-80'" 74 14 441 s 48-59'" 31" 55' 2 56' 6
57 66 52
48
34
34 64 68 0 60 0 23 26 C 57 50 30 56 57
Superscript numbers identify references. The reduction was calculated assuming that the eight-hour average standard would be met if the annual average concentration was 2.3 ppm or less, based upon the paper by Pierrard, Snee, and Zelson.7 c 1973— 74 data; valid 1972 data were unavailable. b
966
Also, there is a discrepancy between the two major COHb research efforts previously mentioned. Although both studies were conducted in the St. Louis area, the samples seem to be taken from entirely different populations. The median COHb levels and the standard deviations of the data differ considerably, as shown in Table III. It appears that some reconciliation of the numbers obtained from the two studies should be developed if these and similar studies are to be used as a basis for evaluating ambient air CO measurements. Discussion
The aforementioned research efforts and data point to one thing: although the clinical evidence of deleterious effects of COHb levels over 2% are well documented, the link between the measurement of CO in the ambient air and COHb levels in the population is not.2 This relationship must be clarified in order to make sense of a national program to protect the public from CO in the ambient air. One major obstacle in clearly defining this link is that most people do not spend the majority of their time in the "ambient" air, defined by the EPA to be: " . . . that portion of the atmosphere, external to buildings, to which the general public has access." 9 People spend most of their time living and working inside buildings, not in the ambient air. The standards which apply to people working in buildings are the Occupational Safety and Health Administration Regulations: the OSHA standard for CO is 50 ppm for an 8 hr average, which is over 5 times the 9 ppm
Journal of the Air Pollution Control Association
Downloaded by [University of Western Ontario] at 21:47 10 November 2014
standard from ambient air. Clearly, if a person spends most of the time in a building, the CO levels to which that person is exposed are a function of the ventilation rate, the place from which ventilation air is drawn, the number of smokers in the immediate vicinity exhausting 200-400 ppm CO with each smoke-laden breath, the work being done, and even the number of people in the vicinity (people are also CO sources). OSHA standards apply inside all buildings in which there is an employer-employee relationship including public buildings. Exposure to "ambient air" for short periods will have little effect on the COHb level of that person, since several hours are required to attain equilibrium between the personal COHb level and the CO concentration in the air the person breathes.1 In fact, the most important health effect related to "ambient air CO" may be that ambient air brought into a building for ventilation contains a "baseline" CO concentration.
. more directed to curbing personal exposure in the working place as is suggested by the St. Louis study.6 Ambient air standards are designed to protect individuals breathing community air. However, these standards do not apply inside public buildings. A careful analysis of the differences between the Occupational Safety and Health Act CO standard, 50 ppm for an 8 hr average, and the ambient air standard of 9 ppm should be conducted to determine if a redefinition of the standards or their applicability is warranted. COHb and ambient air CO data should be evaluated and correlated for several cities, sampling locations, and populations samples to determine if ambient air CO monitoring data can be used to estimate population COHb levels. If, as the St. Louis study suggests, the population COHb burden is more related to place of employment (and therefore the type of ventilation in the workplace, source of ventilation air, the
Table III. Differences between two COHb studies in St. Louis, Missouri.
Study source
Number of samples (Non-Smokers)
5
AMA Journal Archives of Enviro nmental Health4
671
10,157
Geometric mean COHb level (%)
Geometric standard deviation of data
1.4
1.29
0.55
2.55a
sented at the PNWIS-APCA meeting in Seattle, Nov. 28-30,1973. 4. A. Kahn, R. Rutledge, et al., "Carboxyhemoglobin sources in the Metropolitan St. Louis population," Arch. Environ. Health 29:127 (1974). 5. R. Stewart, E. Barrett, et al., "Carboxyhemoglobin levels in American blood donors," J. Amer. Med. Assoc. 229:1187 (Aug 26,1974). 6. W. A. Daniel and J. M. Heuss, "Ambient air quality and automotive emission control," J. Air Poll. Control Assoc. 24: 849 (1974). 7. J. M. Pierrard, R.'D. Snee and J. Zelson, "A new approach to setting vehicle emission standards," J. Air Poll. Control Assoc. 24: 841 (1974). 8. D. Lynn and T. McMullen, "Air pollution in six major U. S. cities as measured by the Continuous Air Monitoring Program," J. Air Poll. Control Assoc 16:186 (1966). 9. "National Primary and Secondary Ambient Air Quality Standards," Federal Register, 36:84 (April 30,1971). 10. Alaska Department of Environmental Conservation Data, 1974. 11. S. Provant, Alaska Operations Office, EPA, personal communication; (October 9,1974). 12. "Transportation Controls to Reduce Motor Vehicle Emissions in Major Metropolitan Areas," APTD 1942, Dec. 1972. 13. "Transportation Control Strategy Development for the Metropolitan Los Angeles Region," APTD 1372, Dec. 1972. 14. "A Transportation Control Strategy for the Phoenix-Tuscon Air Quality Area," APTD 1269, Feb. 1973. 15. C. Copley, Commissioner, Division of Air Pollution Control, City of St. Louis, personal communication; (February 1975). 16. "Transportation Control Plan—National Capital Interstate AQCR," Federal Register 38: 234 (December 6,1973).
a
Calculated from related data given in article.
This concentration would be increased by CO sources or decreased by CO sinks in the building. Therefore, if conditions in a building generally result in substantial changes in this CO concentration "baseline," the COHb levels of people in the buildings will not correspond well with ambient air CO concentrations.
type of work being done, and number of smokers in the vicinity) then a reevaluation of the controls necessary to make reductions in population COHb burden must be made. If the air to which the general public has access is to be suitable for public consumption, then control strategies must be designed to clean up the "accessible air."
Conclusions
References
/ / the carboxyhemoglobin study published in the AMA Journal5 was of a representative sample of the population in the cities studied, and if the CAMP data on which trend analysis was performed came from uniformly sited analyzers,7 then the resulting correlation may be indeed highly significant: the required reductions in measured ambient CO levels may be directly related to the COHb concentration of the population. However, if this is not the case, the CO abatement strategies should be October 1976
Volume 26, No. 10
1. Air Quality Criteria for Carbon Monoxide, National Air Pollution Control Administration Publication No. AP-62, March 1970. 2. "Air Quality and Automobile Emission Control," A Report by the Coordinating Committee on Air Quality Studies, National Academy of Sciences, National Academy of Engineering, U. S. Government Printing Office Serial No. 93-24, Sept. 1974. 3. D. Vidmar and A. Rossano, "An Initial Evaluation of Personal Carbon Monoxide Exposures at Street Level in the Central Business District of Seattle, Washington," Paper No. 73-AP-50 pre-
Mr. Gilmore is an air quality engineer and Mr. Hanna is the air quality control supervisor for the Alaska Department of Environmental Conservation, Pouch O, Juneau, AK 99811.
967
Journal of the Air Pollution Control Association Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/uawm16
The Need for Representative Ambient Air Carbon Monoxide Sampling a
Timothy M. Gilmore & Thomas R. Hanna
a
a
Alaska Department of Environmental Conservation Published online: 13 Mar 2012.
To cite this article: Timothy M. Gilmore & Thomas R. Hanna (1976) The Need for Representative Ambient Air Carbon Monoxide Sampling, Journal of the Air Pollution Control Association, 26:10, 965-967, DOI: 10.1080/00022470.1976.10470345 To link to this article: http://dx.doi.org/10.1080/00022470.1976.10470345
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
The Need for Representative Ambient Air Carbon Monoxide Sampling
Timothy M. Gilmore and Thomas R. Hanna Downloaded by [University of Western Ontario] at 21:47 10 November 2014
Alaska Department of Environmental Conservation
Recent investigations have indicated that ambient air CO measurements may not reflect population exposure to CO. The lack of correlation may be due to improper siting of CO instruments, improper interpretation of air quality data, or both. Studies of population carboxyhemoglobin levels are evaluated and compared with ambient air data., No significant correlation was found between median population COHb levels and reductions in CO concentrations required to meet ambient air standards when calculations used to estimate reductions were based on the second highest 8 hour average. However, calculated reductions based on annual average concentrations and a trend analysis technique correlated significantly with COHb levels in five cities from which both CAMP and COHb data were available. Studies to determine the nature of the relationship between ambient air CO concentrations and population COHb levels are needed. The differences between the Occupational Safety and Health Act Regulations and the National Ambient Air Standards for carbon monoxide should be scrutinized to determine if a redefinition of the standards or their applicability is warranted. A reevaluation of the controls necessary to make reductions in population COHb burden may be necessary.
Since air quality planning and subsequent control strategy implementation involve a considerable economic cost, it is paramount that data upon which plans are formulated be both representative and accurate. The following paper contains a discussion of ambient air CO data interpretation. The document entitled Air Quality Criteria for Carbon Monoxide was published by the National Air Pollution Control Administration in 1970 to provide a background for the subsequent CO Air Quality Standards. 1 These standards were based on findings noted in the criteria document that demonstrable deleterious effects occur when the carboxyhemoglobin (COHb) level of a person exceeds 2%. This COHb level can be reached through an exposure to October 1976
Volume 26, No. 10
approximately 9 ppm of CO in air for 8 hr, which is the promulgated standard. However, there is current evidence that ambient air measurements may not reflect the COHb levels of the population. As the National Academy of Sciences recently concluded: "There is evidence that the monitoring systems currently used may not reflect human carbon monoxide exposure in the general population, and a reevaluation of standardization and operating techniques, as well as location of monitoring stations, is desirable." 2 Interpretation of Ambient Air CO Data
If the CO monitoring locations are representative of population exposure, then one should expect to find some
correlation between the population carboxyhemoglobin levels and the ambient air CO measurements. Recent investigations have revealed conflicting results, however. A study conducted in Seattle concluded that: "Exposure to ambient air in the CBD (Central Business District) can cause significant increases in the carboxyhemoglobin levels of non-smokers." 3 But a study conducted in St. Louis concluded that: "The data analyzed do not indicate a consistent relationship between ambient CO and COHb as would be expected... The increase in COHb levels for non-smokers (as a result of exposure to ambient CO) is quite small." 4 The average COHb levels in several cities in the U. S. described in another study exhibit no correlation with the 965
Downloaded by [University of Western Ontario] at 21:47 10 November 2014
calculated "rollback" of CO concentrations reportedly needed to meet the ambient air CO standards, as shown in Table I and Table II.5 The "rollback" method is based upon the maximum measured outdoor CO concentrations. The poor statistical correlation suggests that the use of maximum measured ambient, or outdoor, concentrations of CO may be an inadequate measure of population COHb concentrations. Another investigation has indicated a great deal of uncertainty in projecting reductions in CO concentrations needed to meet the air quality standards.6 However, calculations of required pollutant reductions in 5 cities based upon annual mean CO concentrations rather than the second highest 8 hr average measurement resulted in a good correlation between the calculated necessary reduction and the median COHb levels in the population, as shown in Tables I and II. Use of annual averages rather than highest measured values may be more meaningful for evaluating population exposures to CO because missing data, instrument malfunctions and possible anomalous occurrences would not tend to be as significant in an annual average. The statistical correlation between population COHb and annual average CO concentrations in 13 cities was not significant, however, as shown in Tables I and II. The use of annual mean CO concentrations was proposed in a paper presented by Pierrard, Snee and Zelson, in which they demonstrated a consistent relationship between the standard deviation of 8 hr averages and the annual
Table II. Correlation between median COHb level and calculated necessary ambient CO concentration reductions for U.S. cities listed in Table I. 1) Calculated reduction from 1972—73 Federal Transportation Control Plans, based on 2nd highest eight hour average CO concentrations. Correlation Coefficient . . .r = —0.116 Number of Data Pairs . . . . n = 13 "t" Test on r t = -0.387 The correlation between the measured COHb and CO concentrations in the thirteen cities is not significantly different from zero 2) Calculated reduction from the 1971 annual average CO concentrations from CAMP sites. Correlation Coefficient. . . r = 0.937 Number of Data Pairs . . . . n = 5 " t " Test on r t = 4.66 Both CAMP and COHb data were available from only five cities. The correlation between measured COHb levels and calculated CO concentration reductions is significant at the 98% confidence level. 3) Calculated reduction from the 1972 annual average CO concentrations from the 13 cities. Correlation Coefficient. . . r = 0.230 Number of Data Pairs . . . . n = 13 "t" Test on r t = 0.786 The correlation between measured COHb levels and calculated CO concentration reductions is not significant. If only the five cities from which CAMP data were available are considered, however, the correlation is significant at the 90% confidence level with a correlation coefficient at 0.87.
mean value of data from several cities using CAMP data.7 This may indicate that a different technique should be considered as the basis for evaluating CO data. The data considered were taken only from CAMP stations for which several years data were available. The correlation may indicate that data from uniformly selected sites may be useful indicators of population COHb. However, it must be noted that the CAMP stations were designed to be representative of a portion of the business district in each city and not for documentation of long term changes in pollution levels.2'8
Table I. Median COHb concentration and calculated reductions necessary to meet ambient air CO standards in some U.S. cities.a
City Anchorage Chicago Denver Detroit Los Angeles New Orleans New York Phoenix St. Louis Salt Lake City San Francisco Seattle Washington, DC a
Median nonsmoker COHb concentration5 (%) 1.5 1.7 2.0 1.6 1.8 1.6 1.2 1.2 1.4
1.2 1.5 1.5 1.2
Calculated necessary reductions From 2nd highest eight hour average, 1972-73 Federal TCP data (%)
From the From the annual average annual average 1971 CAMP 1972 SAROAD data b (%) data b (%)
25'° 50" 64'" 0" 79' 3 0" 72-80'" 74 14 441 s 48-59'" 31" 55' 2 56' 6
57 66 52
48
34
34 64 68 0 60 0 23 26 C 57 50 30 56 57
Superscript numbers identify references. The reduction was calculated assuming that the eight-hour average standard would be met if the annual average concentration was 2.3 ppm or less, based upon the paper by Pierrard, Snee, and Zelson.7 c 1973— 74 data; valid 1972 data were unavailable. b
966
Also, there is a discrepancy between the two major COHb research efforts previously mentioned. Although both studies were conducted in the St. Louis area, the samples seem to be taken from entirely different populations. The median COHb levels and the standard deviations of the data differ considerably, as shown in Table III. It appears that some reconciliation of the numbers obtained from the two studies should be developed if these and similar studies are to be used as a basis for evaluating ambient air CO measurements. Discussion
The aforementioned research efforts and data point to one thing: although the clinical evidence of deleterious effects of COHb levels over 2% are well documented, the link between the measurement of CO in the ambient air and COHb levels in the population is not.2 This relationship must be clarified in order to make sense of a national program to protect the public from CO in the ambient air. One major obstacle in clearly defining this link is that most people do not spend the majority of their time in the "ambient" air, defined by the EPA to be: " . . . that portion of the atmosphere, external to buildings, to which the general public has access." 9 People spend most of their time living and working inside buildings, not in the ambient air. The standards which apply to people working in buildings are the Occupational Safety and Health Administration Regulations: the OSHA standard for CO is 50 ppm for an 8 hr average, which is over 5 times the 9 ppm
Journal of the Air Pollution Control Association
Downloaded by [University of Western Ontario] at 21:47 10 November 2014
standard from ambient air. Clearly, if a person spends most of the time in a building, the CO levels to which that person is exposed are a function of the ventilation rate, the place from which ventilation air is drawn, the number of smokers in the immediate vicinity exhausting 200-400 ppm CO with each smoke-laden breath, the work being done, and even the number of people in the vicinity (people are also CO sources). OSHA standards apply inside all buildings in which there is an employer-employee relationship including public buildings. Exposure to "ambient air" for short periods will have little effect on the COHb level of that person, since several hours are required to attain equilibrium between the personal COHb level and the CO concentration in the air the person breathes.1 In fact, the most important health effect related to "ambient air CO" may be that ambient air brought into a building for ventilation contains a "baseline" CO concentration.
. more directed to curbing personal exposure in the working place as is suggested by the St. Louis study.6 Ambient air standards are designed to protect individuals breathing community air. However, these standards do not apply inside public buildings. A careful analysis of the differences between the Occupational Safety and Health Act CO standard, 50 ppm for an 8 hr average, and the ambient air standard of 9 ppm should be conducted to determine if a redefinition of the standards or their applicability is warranted. COHb and ambient air CO data should be evaluated and correlated for several cities, sampling locations, and populations samples to determine if ambient air CO monitoring data can be used to estimate population COHb levels. If, as the St. Louis study suggests, the population COHb burden is more related to place of employment (and therefore the type of ventilation in the workplace, source of ventilation air, the
Table III. Differences between two COHb studies in St. Louis, Missouri.
Study source
Number of samples (Non-Smokers)
5
AMA Journal Archives of Enviro nmental Health4
671
10,157
Geometric mean COHb level (%)
Geometric standard deviation of data
1.4
1.29
0.55
2.55a
sented at the PNWIS-APCA meeting in Seattle, Nov. 28-30,1973. 4. A. Kahn, R. Rutledge, et al., "Carboxyhemoglobin sources in the Metropolitan St. Louis population," Arch. Environ. Health 29:127 (1974). 5. R. Stewart, E. Barrett, et al., "Carboxyhemoglobin levels in American blood donors," J. Amer. Med. Assoc. 229:1187 (Aug 26,1974). 6. W. A. Daniel and J. M. Heuss, "Ambient air quality and automotive emission control," J. Air Poll. Control Assoc. 24: 849 (1974). 7. J. M. Pierrard, R.'D. Snee and J. Zelson, "A new approach to setting vehicle emission standards," J. Air Poll. Control Assoc. 24: 841 (1974). 8. D. Lynn and T. McMullen, "Air pollution in six major U. S. cities as measured by the Continuous Air Monitoring Program," J. Air Poll. Control Assoc 16:186 (1966). 9. "National Primary and Secondary Ambient Air Quality Standards," Federal Register, 36:84 (April 30,1971). 10. Alaska Department of Environmental Conservation Data, 1974. 11. S. Provant, Alaska Operations Office, EPA, personal communication; (October 9,1974). 12. "Transportation Controls to Reduce Motor Vehicle Emissions in Major Metropolitan Areas," APTD 1942, Dec. 1972. 13. "Transportation Control Strategy Development for the Metropolitan Los Angeles Region," APTD 1372, Dec. 1972. 14. "A Transportation Control Strategy for the Phoenix-Tuscon Air Quality Area," APTD 1269, Feb. 1973. 15. C. Copley, Commissioner, Division of Air Pollution Control, City of St. Louis, personal communication; (February 1975). 16. "Transportation Control Plan—National Capital Interstate AQCR," Federal Register 38: 234 (December 6,1973).
a
Calculated from related data given in article.
This concentration would be increased by CO sources or decreased by CO sinks in the building. Therefore, if conditions in a building generally result in substantial changes in this CO concentration "baseline," the COHb levels of people in the buildings will not correspond well with ambient air CO concentrations.
type of work being done, and number of smokers in the vicinity) then a reevaluation of the controls necessary to make reductions in population COHb burden must be made. If the air to which the general public has access is to be suitable for public consumption, then control strategies must be designed to clean up the "accessible air."
Conclusions
References
/ / the carboxyhemoglobin study published in the AMA Journal5 was of a representative sample of the population in the cities studied, and if the CAMP data on which trend analysis was performed came from uniformly sited analyzers,7 then the resulting correlation may be indeed highly significant: the required reductions in measured ambient CO levels may be directly related to the COHb concentration of the population. However, if this is not the case, the CO abatement strategies should be October 1976
Volume 26, No. 10
1. Air Quality Criteria for Carbon Monoxide, National Air Pollution Control Administration Publication No. AP-62, March 1970. 2. "Air Quality and Automobile Emission Control," A Report by the Coordinating Committee on Air Quality Studies, National Academy of Sciences, National Academy of Engineering, U. S. Government Printing Office Serial No. 93-24, Sept. 1974. 3. D. Vidmar and A. Rossano, "An Initial Evaluation of Personal Carbon Monoxide Exposures at Street Level in the Central Business District of Seattle, Washington," Paper No. 73-AP-50 pre-
Mr. Gilmore is an air quality engineer and Mr. Hanna is the air quality control supervisor for the Alaska Department of Environmental Conservation, Pouch O, Juneau, AK 99811.
967
