Lead in Outdoor Air
Sources of Lead in the Air
Sources of lead emissions vary from one area to another. EPA has a national database that shows which types of sources contribute to the total lead emitted into the air each year on a national, state, and local level. At the national level, major sources of lead in the air are ore and metals processing and piston-engine aircraft operating on leaded aviation fuel. Other sources are waste incinerators, utilities, and lead-acid battery manufacturers. The highest air concentrations of lead are usually found near lead smelters.
As a result of EPA's regulatory efforts to remove lead from motor vehicle gasoline, levels of lead in the air decreased by 89 percent between 1980 and 2010.
Lead in the air is a problem not only because people may breathe it in, but also because people, particularly children, can swallow lead dust that has settled onto surfaces like soil, dust, and water. Lead in soil and dust stays around for many years because it does not decay or decompose.
National Standards for Lead in the Air
To protect public health and the environment, the Clean Air Act requires EPA to set National Ambient Air Quality Standards (NAAQS) for six common pollutants including lead. EPA works with state, local, and tribal air quality agencies to meet these standards.
EPA also uses the monitoring data to determine which areas are not meeting the national lead standards. If an area continues to have air pollution levels greater than the standards, it may be designated "nonattainment." EPA keeps a list of current nonattainment areas for lead.
If an area is designated nonattainment, its state must make a plan to clean up the polluted area and keep it clean. This plan is called a State Implementation Plan (SIP).
Read more about EPA regulations related to the national standards for lead and monitoring.
Emissions Limits for Lead from Industries
The Clean Air Act includes lead in its list of toxic air pollutants (also known as hazardous air pollutants). EPA sets limits called NESHAPs (National Emission Standards for Hazardous Air Pollutants) for industrial sources that emit significant amounts of one or more of the toxic air pollutants. Most NESHAPs limit lead as part of a group of hazardous air pollutant metals, but the NESHAPs for Primary and Secondary Lead Smelting have limits specifically for lead.