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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Summary: Federal Plan for Particulate Matter in Phoenix

In response to a court order, on July 17, 1998 EPA issued a Federal Implementation Plan (FIP) for reducing particulate matter (PM-10), or dust, in Maricopa County, Arizona. PM-10 is particulate matter with a diameter of 10 microns or less (a human hair has a diameter of 70 microns). It may affect the respiratory system and can cause severe damage to lung tissue and premature death. The elderly, children, and people with chronic lung disease, influenza, or asthma are especially sensitive to high levels of particulate matter.

What does the Federal plan require?

The federal plan requires owners or operators of certain unpaved parking lots, unpaved roads and disturbed vacant lots to control dust. After May 1, 1999, EPA began conducting inspections to make sure that dust sources are properly controlled.

Who has to comply with the federal plan?

The rule applies to owners and operators of: 1) unpaved parking lots greater than 5000 square feet that have more than 10 cars parked on them per day; 2) unpaved roads which receive 250 or more vehicle trips per day; 3) vacant lots which are either greater than 5,000 square feet that are disturbed by vehicle trespassing or are ½ acre or greater with at least ½ acre of disturbed surface area. For lots disturbed by weed abatement, the person(s) responsible for the weed abatement, if not the vacant lot owner, must comply with the rule.

How can dust be controlled?

The federal plan includes several approaches, or control measures, for controlling dust. These include, but are not limited to:

  • applying gravel, chemical or organic soil stabilizers, or paving over unpaved parking lots and unpaved roads frequently travelled
  • applying water or other dust suppressants when vacant lots are weeded.
  • applying dust suppressants or revegetating vacant lots disturbed by vehicles or other activities.
  • fencing off or placing barriers on vacant lots to prevent vehicles from trespassing.

Two other major sources of dust are construction sites and agricultural fields. Maricopa County currently has a program which controls dust from construction sites. The State of Arizona is working with stakeholders to develop approaches, or "best management practices," which farmers can use to control dust from agricultural fields.

For more information:

Please contact Colleen McKaughan, Associate Director, air Division, U.S. EPA Region 9 at (520) 498-0118. Send questions and comments to r9.phoenixdust@epa.gov.
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