EPA is proposing to expand the lead air quality monitoring network to ensure that the most vulnerable Americans are protected from exposure to lead. Even at low levels, exposure to lead can impair a child’s IQ, learning capabilities, memory and behavior.

EPA is proposing to require air quality monitoring around sources that emit a half ton or more of lead a year, lowering the current threshold from one ton a year to include more sources. The proposal also modifies the current requirement for monitoring in larger urban areas. Monitors would be placed at each of the multi-pollutant monitoring stations being established in urban and rural areas.

These changes would allow monitoring at the largest sources of lead emissions and would more accurately track long-term trends and assess typical lead levels in communities throughout the country.

This proposal is in response to a petition for reconsideration requesting EPA to reevaluate the air monitoring requirements finalized in 2008 along with the tightened national air quality standards for lead.

EPA is not reconsidering, nor is it delaying the implementation of, the 2008 lead standards. States will still need to deploy lead monitors around sources emitting at least one ton of lead a year by January 1, 2010.

Lead emitted into the air can be inhaled or can be ingested after it settles. Ingestion is the main route of human exposure. Children are the most susceptible because they are more likely to ingest lead, and their bodies are developing rapidly. There is no known safe level of lead in the body.

EPA will accept comments on the proposal for 45 days after it is published in the Federal Register.