Air Quality Standards for Lead Now 10 Times Stronger
EPA recently strengthened the nation's air quality standards for lead, improving public health protection, especially for children. The new standards tighten the allowable lead level 10 times to 0.15 micrograms of lead per cubic meter of air (ug/m3).
"America's air is cleaner than a generation ago," said EPA Administrator Stephen L. Johnson. "With these stronger standards a new generation of Americans are being protected from harmful lead emissions."
This decision marks the first time the lead standards have changed in 30 years. EPA strengthened the standards after a thorough review of the science on lead, advice from the Clean Air Scientific Advisory Committee, and consideration of public comments. The previous standards, set in 1978, were 1.5 ug/m3.
EPA's action sets two standards: a primary standard at 0.15 ug/m3 to protect health and a secondary standard at the same level to protect the public welfare, including the environment.
The existing monitoring network for lead is not sufficient to determine whether many areas of the country would meet the revised standards. EPA is redesigning the nation's lead monitoring network, which is necessary for the agency to assess compliance with the new standard.
No later than October 2011, EPA will designate areas that must take additional steps to reduce lead air emissions. States have five years to meet these new standards after designations take effect.
More than 6,000 studies since 1990 have examined the effects of lead on health and the environment. Some studies have linked exposure to low levels of lead with damage to child development, including IQ loss.
Lead can be inhaled or can be ingested after settling out of the air. Ingestion is the main route of human exposure. Once in the body, lead is rapidly absorbed into the bloodstream and can affect many organ systems including children's developing nervous systems.
Lead emissions have dropped nearly 97 percent nationwide since 1980, largely the result of the agency's phase-out of lead in gasoline. Average levels of lead in the air today are far below the 1978 standards. Lead in the air comes from a variety of sources, including smelters, iron and steel foundries, and general aviation gasoline. More than 1,300 tons of lead are emitted to the air each year, according to EPA's most recent estimates.
Since September 2006, EPA has strengthened air quality standards for lead, ground-level ozone and particulate matter.