The EPA natural events policy as applied to high-wind PM10 exceedances in the Coachella Valley

Conference · Thu Dec 31 04:00:00 EST 1998

OSTI ID:361953

Durkee, K R ^[1]

---

1. South Coast Air Quality Management District, Diamond Bar, CA (United States)

In May of 1996, the US Environmental Protection Agency (EPA) promulgated a natural events policy for particulate matter having a nominal aerodynamic diameter less than or equal to 10 microns (PM10). The policy permits the exclusion of ambient air quality data attributable to certain extraordinary natural events (i.e., volcanic and seismic activity, wildland fires and high winds). If a state or local air district can adequately document that an exceedance of the PM10 national ambient air quality standards (NAAQS) is caused by a qualifying natural event, the data will be flagged in the EPA Air Information Retrieval System (AIRS) database and it can be excluded from the determination of NAAQS compliance. Southern California`s Coachella Valley has had five days with 24-hour average PM10 concentrations above the NAAQS (i.e., exceeding 150 m g/m{sup 3}) during the period from 1993 to the present, as measured every six days with size selective inlet (SSI) samplers. Each of these has been documented and submitted by the South Coast Air Quality Management District (SCAQMD) as a high-wind natural event under the natural events policy. In this paper, three case studies provide a comprehensive range of meteorological conditions that lead to high winds and windblown dust events and illustrate the variety of analytical techniques used to prove each case as a natural event.

• OSTI ID: 361953
• Report Number(s): CONF-980632--
• Country of Publication: United States
• Language: English

Related Subjects

29 ENERGY PLANNING, POLICY, AND ECONOMY
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
CALIFORNIA
ENVIRONMENTAL POLICY
ENVIRONMENTAL TRANSPORT
METEOROLOGY
PARTICLE SIZE
PARTICULATES
STANDARDS
WIND