History of Lead Air Quality Standard

This page reviewed November 24, 2009.
What is lead?
Lead is a relatively soft and chemically resistant metal. Lead forms compounds with both organic and inorganic substances. As an air pollutant, lead is present in small particles. Sources of lead emissions in California include a variety of industrial activities. Because it was emitted in large amounts from vehicles when leaded gasoline was used, lead is present in many soils (especially urban soils) and can get resuspended into the air.
Health and Welfare Effects from Exposure to Ambient Levels of Lead
Because lead is only slowly excreted, exposures to small amounts of lead from a variety of sources can accumulate to harmful levels. Effects from inhalation of lead near the level of the ambient air quality standard include impaired blood formation and nerve conduction. Lead can adversely affect the nervous, reproductive, digestive, immune, and
blood-forming systems. Symptoms can include fatigue, anxiety, short-term memory loss, depression, weakness in the extremities, andlearning disabilities in children. Lead also causes cancer.
History of Lead Air Quality Standard
  • In 1970, the ARB set a standard for lead at 1.5 µg/m3 for a 30-day average.

  • In 1976, the ARB reviewed and retained this standard.

  • In 1993, the ARB identified lead compounds (including inorganic lead) as toxic air contaminants, due to
    cancer effects.

  • In 1996, the ARB established a cancer potency value of 1.2 x 10-5 per µg/m3 for inorganic lead exposure.
    This value also applies to lead acetate, lead phosphate and lead subacetate.
Ongoing Regulatory Activities
Based on the identification of lead as a toxic air contaminant, the ARB staff is involved in risk management activities for lead. For more information on Lead Risk Management Activities, please click here.

 For more information on Ambient Air Quality Standards, please contact
Linda Smith at (916) 327-8225 or email at lsmith@arb.ca.gov.



Ambient Air Quality Standards

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