Children at Risk from Ozone Air Pollution -- United States, 1991-1993

A national health objective for the year 2000 is to reduce exposure to air pollutants so that at least 85% of persons reside in counties that meet Environmental Protection Agency (EPA) standards (objective 11.5) (1). Ozone, the principle component of summer smog, is the most pervasive air pollutant in the United States. The risks associated with ozone and other air pollutants are especially increased for children and adults with asthma (2); however, children with no underlying pulmonary diseases also are at risk for adverse health effects associated with these pollutants (3). In addition, because children of racial/ethnic minorities are more likely to reside in areas with higher air pollution levels, they may be exposed to higher levels of ozone (4). This report presents the findings of an analysis by the American Lung Association (ALA) to characterize pediatric populations potentially at risk for adverse health effects from exposure to ozone air pollution in the United States during 1991-1993.

The National Ambient Air Quality Standard for ozone is 0.12 parts per million (ppm) averaged over 1 hour. * The federal standard is met if this value is not exceeded more than once per calendar year on average over a 3-year period. The federal "exceedance" of the 0.12 ppm standard is defined as all levels greater than or equal to 0.125 ppm. ** For this report, both the federal exceedance level (greater than or equal to 0.125 ppm, averaged over 1 hour) and an alternative level -- used in recent health studies (greater than or equal to 0.085 ppm, averaged over 8 hours) (5 ) -- were used as cutoff values.

The 1990 population census provided race/ethnicity-specific data for persons aged less than or equal to 17 years in each county (Bureau of the Census, unpublished data, 1992). The number of children with asthma was estimated by applying age-specific national prevalence rates from CDC's National Health Interview Survey (6) to age-specific population estimates at the county level. Information about ozone exposure was based on 1991-1993 monitored ozone data (EPA, unpublished data, 1994), the most recent data available from EPA. Although individual levels of ozone exposure may vary for persons who reside in a particular county and differ from those measured by the monitor in that county, ozone levels generally are consistent within specific geographic areas (7).

During 1991-1993, ozone levels exceeded 0.085 ppm over 8 hours on four or more occasions in 394 counties and cities; an estimated 136 million persons (54.7% of the U.S. population) resided in these areas. Of the total number of children aged less than or equal to 13 years in the United States (50,324,764), approximately 27.1 million (53.9%) resided in these areas. Among racial/ethnic groups, 61.3% of all black children, 67.7% of all Asian/ Pacific Islander children, and 69.2% of all Hispanic children resided in these areas Table_1. An estimated 2.0 million (5.8%) of the 34.3 million children (aged less than or equal to 17 years) residing in these areas were affected by asthma.

During 1991-1993, a total of 104 counties and cities had ozone levels greater than 0.125 ppm over a 1-hour period on four or more occasions. An estimated 60 million persons in the United States (24.1% of the U.S. population) resided in these areas, including an estimated 12.1 million children (aged less than or equal to 13 years) (24.1% of all children in this age group). Among racial/ethnic groups, 23.1% of black children, 39.9% of Asian/Pacific Islander children, and 44.2% of Hispanic children resided in these areas Table_2. Approximately 877,000 children (aged less than or equal to 17 years) in these areas were affected by asthma. Reported by: R White, MST, National Programs Div, S Rappaport, MPH, K Lieber, MPH, A Gorman, Epidemiology and Statistics Div, F DuMelle, D Maple, Government Relations Div, M Bhawnani, Communications Div, N Edelman, MD, American Lung Association, New York. Air Pollution and Respiratory Health Br, Div of Environmental Hazards and Health Effects, National Center for Environmental Health, CDC.

Editorial Note

Editorial Note: Ozone pollution results when hydrocarbons and nitrogen oxides emitted from motor vehicles and other sources react in the presence of sunlight. Exposure to ozone has been associated with adverse health effects, including hospital and emergency department visits for asthma and other respiratory problems; reductions in lung function; and exercise-related wheezing, coughing, and chest tightness (5). Children are at higher risk for detrimental effects of ozone than adults because they spend more time outdoors during summer months when ozone levels are higher and because their lungs are still developing (8).

Although air pollution has been recognized as a public health hazard in the United States since the 1950s, the disproportionate risks for racial/ethnic minorities with low incomes have only recently been recognized (4). The findings in this report underscore the increased risk for exposure -- particularly among children -- for racial/ethnic minorities who reside in areas where national air quality standards are not met (4). In addition, since the early 1980s, the risk for asthma-associated mortality and hospitalization has been consistently higher among young persons who are black (9).

ALA recently issued Danger Zones: Ozone Air Pollution and Our Children. The report is a national and county estimate of the number of children who are at potential risk from exposure to ozone. Copies are available from local offices of the ALA, telephone (800) 586-4872 or (212) 315-8700.

References

1. Public Health Service. Healthy people 2000: national health promotion and disease prevention objectives. Washington, DC: US Department of Health and Human Services, Public Health Service, 1991; DHHS publication no. (PHS)91-50213.

2. CDC. Populations at risk from air pollution -- United States, 1991. MMWR 1993;42:301-4.

3. Committee on Environmental Health. Ambient air pollution: respiratory hazards to children. Pediatrics 1993;91:1210-3.

4. US Environmental Protection Agency. Environmental equity: reducing risk for all communities. Volume 1: workgroup report to the Administrator. Washington, DC: US Environmental Protection Agency, Office of Policy, Planning, and Evaluation, June 1992; publication no. EPA-230/R-92/008.

5. Lippmann M. Health effects of tropospheric ozone: review of recent research findings and their implications to ambient air quality standards. J Expo Anal Care Environ Epidemiol 1993;3:103-6.

6. NCHS. Current estimates from the National Health Interview Survey, 1990. Hyattsville, Maryland: US Department of Health and Human Services, Public Health Service, CDC, 1991; DHHS publication no. (PHS)92-1509. (Vital and health statistics; series 10, no. 181).

7. Curran T, Fitz-Simons T, Freas W, et al. National air quality and emissions trends report, 1993. Research Triangle Park, North Carolina: US Environmental Protection Agency, Office of Air Quality Planning and Standards, October 1994; publication no. EPA-454/R-94/026.

8. World Health Organization. Principles for evaluating health risks from chemicals during infancy and early childhood: the need for a special approach. Geneva: World Health Organization, 1986; environmental criteria 59.

9. CDC. Asthma -- United States, 1982-1992. MMWR 1995;43:952-5.

* 44 FR 8202. 

** 40 CFR 50.

TABLE 1. Estimated number and percentage * of persons aged <= 13 years exposed to
ozone levels >= 0.085 ppm over an 8-hour period on four or more occasions, by
race/ethnicity and age group -- United States, 1991-1993
=========================================================================================================
                                               Age group (yrs)
                     -------------------------------------------------------------------
                             0-4                    5-13                    Total
                     -------------------     -------------------     -------------------
Race/Ethnicity           No.       (%)           No.       (%)           No.       (%)
----------------------------------------------------------------------------------------
White                 7,024,973   (51.5)     12,105,966   (50.4)     19,130,940   (50.8)
Black                 1,726,730   (62.0)      2,915,656   (60.9)      4,642,386   (61.3)
American Indian/
  Alaskan Native         57,562   (28.5)        102,586   (29.2)        160,149   (28.9)
Asian/ Pacific
  Islander              400,682   (67.6)        702,920   (67.6)      1,103,601   (67.7)
Hispanic +            1,665,225   (69.7)      2,628,432   (68.9)      4,293,657   (69.2)
Other &                 821,455   (72.9)      1,272,863   (72.4)      2,094,318   (72.6)

Total                10,031,403   (54.7)     17,099,991   (53.5)     27,131,394   (53.9)
----------------------------------------------------------------------------------------
* Percentage of race/ethnicity-specific and age-specific population (e. g., percentage of blacks
  aged <5 years) residing in these areas.
+ Persons of Hispanic origin can be of any race and therefore are represented in the other five
  racial categories.
& Includes all other persons not included in white, black, American Indian/Alaskan Native, or
  Asian/Pacific Islander groups (e. g., multiracial, multiethnic, mixed, and interracial) or a Spanish/
  Hispanic origin group (e. g., Mexican, Cuban, or Puerto Rican).
=========================================================================================================

TABLE 2. Estimated number and percentage * of persons aged <= 13 years exposed to
ozone levels >= 0.125 ppm over a 1-hour period on four or more occasions, by
race/ethnicity and age group -- United States, 1991-1993
===================================================================================================
                                            Age group (yrs)
                     -----------------------------------------------------------------
                            0-4                    5-13                   Total
                     ------------------     ------------------     -------------------
Race/Ethnicity          No.       (%)          No.       (%)           No.       (%)
--------------------------------------------------------------------------------------
White                3,077,213   (22.5)     5,155,003   (21.4)      8,232,215   (21.8)
Black                  658,805   (23.6)     1,089,974   (22.8)      1,748,779   (23.1)
American Indian/
  Alaskan Native        24,388   (12.1)        43,000   (12.2)         67,388   (12.2)
Asian/Pacific
  Islander             236,856   (40.2)       413,419   (39.8)        650,276   (39.9)
Hispanic +           1,070,046   (44.8)     1,667,656   (43.7)      2,738,062   (44.2)
Other &                558,082   (49.5)       857,686   (48.8)      1,415,768   (49.1)

Total                4,555,344   (24.8)     7,559,082   (23.6)     12,114,426   (24.1)
--------------------------------------------------------------------------------------
* Percentage of race/ethnicity-specific and age-specific population (e. g. percentage of blacks
  aged <5 years) residing in these areas.
+ Persons of Hispanic origin can be of any race and therefore are represented in the other five
  racial categories.
& Includes all other persons not included in white, black, American Indian/Alaskan Native,
  or Asian/Pacific Islander groups (e. g., multiracial, multiethnic, mixed, and interracial) or a
  Spanish/Hispanic origin group (e. g., Mexican, Cuban, or Puerto Rican).
===================================================================================================

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