The Mott Street air monitoring station was established to determine the effect air emissions on air quality in the vicinity of the primary lead smelter facility in Herculaneum.  The facility has since ceased the smelting of lead concentrates as per order of 2013 Consent Decree with the EPA but continue to operate lead refinery activities. Lead monitoring continues at the site to continue assessing lead concentrations in the lead non-attainment area, and monitoring is required by the consent agreement.  Monitoring at this location is done by both the State and the Doe Run Company. 



The primary and secondary ambient air standards for lead have remained at 0.15 micrograms per cubic meter since 2008. The primary standard reflects EPA's concern for public health while the second standard demonstrates concern for public welfare. EPA bases the standard on the highest rolling three-month average over a period of three years and two months. A monitoring site meets the standard when this rolling three-month average is less than or equal to 0.15 μg/m3.

Departmental information about lead

  • Health effects
  • Missouri's lead legacy
  • 2008 standard and pertinent documents

Sulfur Dioxide

EPA not only established a new one-hour standard in 2010, but it also introduced a new form for determining compliance. The new form requires three years of data — the average SO2 concentration from each hour of the year. The department and EPA calculate the design value, using the 99th percentile of one-hour daily maximum concentrations, averaged over three years.

Departmental information about sulfur dioxide (SO2)

  • Description
  • 2010 standard and related documents
Herculaneum Mott Street Air Monitoring Site

747 Mott St.
Herculaneum, MO 63048
United States

Date Established
Pollutants Monitored
Sulfur Dioxide
38.263394, -90.37967