Lead is a toxic, naturally occurring metal used in some manufactured products found in and around the home (such as paints made before 1978). The major source of lead emissions was once from the combustion of leaded gasoline. Removing lead from gasoline reduced lead emissions by 95 percent between 1980 and 1999. Today the sources of highest lead emissions are from lead smelters, waste incinerators, coal combustion, lead-acid battery manufacturers, and piston aircraft burning leaded aviation gasoline.
The EPA health standard for lead emissions was recently lowered from 1.5 micrograms per cubic meter of air (μg/m3) to 0.15 (μg/m3) to increase protection for children and others at-risk for lead exposure. Lead is persistent in the environment and accumulates in soils and sediments when lead emitted into the air settles to the ground or is captured in falling raindrops. Lead which has previously accumulated on the ground or in the soil can be re-emitted if disturbed, for example, by a construction project.
Airborne lead can be inhaled or ingested. Ingestion is the main route of human exposure. Once in the body, lead distributes throughout the blood circulation system and builds up in the bones. Lead is associated with a broad range of health effects, including the oxygen-carrying capacity of the blood, central nervous system, cardiovascular system, kidneys and immune system.
Children are more vulnerable than adults to the damaging effects of lead. They breathe 1.5 times as much air proportionately than adults. Children typically spend more time outdoors and are more physically active. Lead exposure also occurs through hand-to-mouth activities. Because children’s brains are still developing, they are more susceptible to the poisonous effect.
Federal regulations require lead ambient air monitors be placed at facilities that emit at least.0.5 tons per year and where urban areas have a population of 500,000 people or more beginning in 2012.
For more information about lead, go to www.epa.gov/air/lead/.