# Ambient Air Quality Surveillance for Lead
> **Rule** · Direct final rule. · Published 1997-11-05 · Effective 1997-12-22 · 62 FR 59813
## Document
- **Document number:** 97-29294
- **Category:** air-emissions
- **Federal Register citation:** 62 FR 59813
- **CFR reference:** 40 CFR 58
- **Publication date:** 1997-11-05
- **Effective date:** 1997-12-22
- **EPA docket:** AD-FRL-5903-5
## Abstract

Lead air pollution levels measured near the Nation's roadways have decreased 97 percent between 1976 and 1995 with the elimination of lead in gasoline used by on-road mobile sources. Because of this historic decrease, EPA is shifting its ambient air monitoring focus from measuring lead air pollutant concentrations emanating from mobile source emissions toward a focus on stationary point sources of lead air pollution. Today's action revises the part 58 lead air monitoring regulations to allow many lead monitoring stations to be discontinued while maintaining a core lead monitoring network in urban areas to track continued compliance with the lead National Ambient Air Quality Standard (NAAQS). This action also requires lead ambient air monitoring around lead stationary sources. This action is being taken at the direct request of numerous State and local agencies whose on-road mobile source-oriented lead monitors have been reporting peak lead air pollution values that are many times less than the quarterly lead NAAQS of 1.5 <greek-m>g/m\3\ for many years. Approximately 70 of the National Air Monitoring Stations (NAMS) and a number of the State and Local Air Monitoring Stations (SLAMS) could be discontinued with this action, thus making more resources available to those State and local agencies to deploy lead air quality monitors around heretofore unmonitored lead stationary sources.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1997/11/05/97-29294/ambient-air-quality-surveillance-for-lead)
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