The Southland’s air quality agency is working with local government to prepare a new dust control plan for the Coachella Valley this year to reduce particulate pollution levels and protect residents’ health.
"Dust control measures implemented in the early 1990s significantly reduced particulate pollution, but a building boom and other factors have led to unhealthful levels during the past three years," said Barry Wallerstein, executive officer for the South Coast Air Quality Management District.
At issue is PM10 or particles about 1/7 the diameter of a human hair that obscure visibility, and evade the respiratory system’s defense mechanisms to lodge deep in lungs. Exposure to unhealthful levels of PM10 is associated with exacerbation of chronic respiratory diseases, increased hospitalizations and even premature deaths.
To reduce particulate pollution, AQMD will work with the Coachella Valley Association of Governments, representatives from industry and the public to develop a new dust control plan by this summer. The U.S. Environmental Protection Agency and the California Air Resources Board must approve the plan.
In the Coachella Valley, PM10 is primarily comprised of windblown dust from land development activities, agricultural tilling, unpaved roads and dirt on paved roadways that is suspended in the air when vehicles drive over it.
After six years of meeting the federal three-year-average PM10 health standard, levels in the Coachella Valley slightly exceeded the standard in 1999, 2000 and 2001. (The 2001 level is preliminary and subject to final review.) The federal health standard is 50 micrograms of PM10 per cubic meter of air on an annual average basis. The level was 52.7 in 1999, 51.9 in 2000 and 50.6 in 2001, all at the Indio air monitoring station, which typically experiences the highest PM10 levels in the valley because it is downwind of particulate sources.
The reported annual PM10 levels do not include the impact from sand and dust storms that occur on days when winds exceed 25 miles per hour. EPA excludes these conditions if man-made dust sources are controlled and a system for notifying the public of high wind forecasts is in place.
AQMD first developed a PM10 control plan for the valley in 1990, and updated it in 1994, with an anticipated attainment demonstration by 2001. Due to the last three years of air quality data, AQMD now will request an extension from EPA to 2006, or sooner if possible, based on the new plan.
"The new plan will contain more stringent dust control measures than are now in effect," Wallerstein said. "It’s important to adopt these measures to prevent the federal government from imposing its own plan on the Coachella Valley."
The Coachella plan will need to incorporate so-called Most Stringent Measures, which already have been adopted in the Phoenix area. Based on measures adopted elsewhere, the Coachella Valley plan could include requirements such as:
Last year, in response to a significant increase in dust complaints from the valley, AQMD assigned a full-time air quality inspector to the area to enforce dust regulations and educate businesses and local governments on air quality requirements.
"Increased enforcement and a renewed commitment by businesses and local governments to control dust have contributed to a downward trend in PM10 levels during the past three years," Wallerstein said. "Now we need to redouble our efforts with this new plan to restore healthful air quality to the valley."
AQMD is the air pollution control agency for Orange County and major portions of Los Angeles, San Bernardino and Riverside counties.
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AQMD Home Page
This page updated: March 01, 2004
URL: http://www.aqmd.gov/news1/Coachella_Plan.htm