America's Children: Key National Indicators of Well-Being, 2011
Outdoor Air Quality
The environment in which children live plays an important role in their health and development. Children may be more vulnerable than adults to the adverse effects of environmental contaminants in air, food, drinking water, and other sources because their bodies are still developing. In addition, children have increased potential for exposure to pollutants because they eat, drink, and breathe more, in proportion to the size of their bodies, than adults. One important measure of children's environmental health is the percentage of children living in areas in which air pollution levels are higher than the allowable levels of the Primary National Ambient Air Quality Standards.51 These standards, established by the Environmental Protection Agency under the Clean Air Act, are designed to protect public health, including the health of susceptible populations such as children. Ozone, particulate matter, sulfur dioxide, and nitrogen dioxide are air pollutants associated with increased asthma episodes and other respiratory illnesses in children. These problems can lead to increased emergency room visits and hospitalizations.52, 53, 54, 55 Lead can affect the development of the central nervous system in young children,56 and exposure to carbon monoxide can reduce the capacity of blood to carry oxygen.57
Indicator Phys1.A: Percentage of children ages 0–17 living in counties in which levels of one or more air pollutants were above allowable levels, 1999–2009
NOTE: Data have been revised since previous publication in America's Children. Values have been recalculated based on updated data in the Air Quality System. This analysis incorporates the revised Primary National Ambient Air Quality Standards for nitrogen dioxide and sulfur dioxide that were promulgated in 2010. The PM2.5 24-hour standard, promulgated in 2006, has also been added to the figure. Averaging time of ambient pollutant concentrations varies by pollutant: 1 hour for nitrogen dioxide and sulfur dioxide; 8 hours for ozone and carbon monoxide; 24 hours for PM10; and 3 months for lead. Two different averaging times are considered for PM2.5: 24-hour and annual.
SOURCE: Environmental Protection Agency, Office of Air and Radiation, Air Quality System.
- In 2009, 59 percent of children lived in counties in which one or more air pollutants were above the allowable levels defined by the Primary National Ambient Air Quality Standards.
- Ozone is the pollutant that is most often above allowable levels. In 2009, 49 percent of children lived in counties in which ozone concentrations were above allowable levels.
- In 2009, approximately 32 percent of children lived in counties where levels of fine particulate matter (PM2.5) were above the 24-hour allowable level, compared with 55 percent in 1999. The term "particulate matter" (PM) includes both solid particles and liquid droplets found in air.55 Airborne particles measuring less than 10 micrometers in diameter (PM10) pose a health concern because they can be inhaled into and accumulate in the respiratory system. Particles less than 2.5 micrometers in diameter (PM2.5) are referred to as "fine" particles and are believed to pose the larger health risks because they can lodge deeply in the lungs, even with intermittent exposure.
- From 1999–2009, the percentage of children living in counties that exceeded the current 1-hour standard for sulfur dioxide declined from about 31 percent to about 11 percent. Over the same years, the percentage of children living in counties that exceeded the current 1-hour standard for nitrogen dioxide decreased from about 23 percent to about 9 percent.
51 This measure does not differentiate between counties in which the Primary National Ambient Air Quality Standards are exceeded frequently or by a large margin and counties in which the standards are exceeded only rarely or by a small margin. It must also be noted that this analysis differs from the analysis utilized by the U.S. Environmental Protection Agency for the designation of "nonattainment areas" for regulatory compliance purposes.
52 U.S. Environmental Protection Agency. (2008). Integrated Science Assessment for Sulfur Oxides—Health Criteria (Final Report) (EPA/600/R-08/047F). Washington, DC: U.S. EPA, National Center for Environmental Assessment. Retrieved from http://cfpub.epa.gov/ncea/isa/recordisplay.cfm?deid=198843.
53 U.S. Environmental Protection Agency. (2008). Integrated Science Assessment for Oxides of Nitrogen—Health Criteria (EPA/600/R-08/071). Research Triangle Park, NC: Author.
54 U.S. Environmental Protection Agency. (2006). Air quality criteria for ozone and related photochemical oxidants (EPA/600/ R-05/004aF). Research Triangle Park, NC: Author.
55 U.S. Environmental Protection Agency. (2009). Integrated Science Assessment for Particulate Matter (Final Report) (EPA/600/R-08/139F). Washington, DC: U.S. EPA, National Center for Environmental Assessment. Retrieved from http://cfpub.epa.gov/ncea/CFM/recordisplay.cfm?deid=216546.
56 U.S. Environmental Protection Agency. (2006). Air quality criteria for lead: Volume I (EPA/600/R-05/144aF). Research Triangle Park, NC: Author.
57 U.S. Environmental Protection Agency. (2010). Integrated Science Assessment for Carbon Monoxide (Final Report) (EPA/600/R-09/019F). Washington, DC: U.S. EPA, National Center for Environmental Assessment. Retrieved from http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=218686.