The Maricopa County Air Quality Department has the following purpose statement “Working to improve the air of Maricopa County so customers, residents, and visitors can live, work, and play in a healthy environment”. One way to accomplish this is to enforce a strict set of rules that govern specific types pollution and pollution producing activities. One specific pollutant that plagues arid desert areas is particulate matter. So, how much particulate matter, or PM for short is too much and where does it come from?

Air-born particulate matter is measured by both size and concentration. When particulates are grouped into classes based on size (parts per million); PM10: inhalable particles, with diameters that are generally 10 micrometers and smaller; and PM2.5: fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller. As for concentration the Environmental Protection Agency (EPA) has determined through hundreds of scientific research papers based on health indicators that the allowable concentration is defined as follows, per County Rule 510 s302 PARTICULATE MATTER - 10 MICRONS OR LESS (PM10), Primary and Secondary Ambient Air Quality Standard for PM10:

The primary and secondary ambient air quality standards for PM10 shall be 150 µg/m3 24-hour average concentration. The standards shall be considered attained when the expected number of days per calendar year with a 24-hour average concentration above 150 µg/m3, as determined in accordance with 40 CFR 50, Appendix K, is less than or equal to one.

How the standards are set: https://www.epa.gov/pm-pollution/setting-and-reviewing-standards-control-particulate-matter-pm-pollution

The Air Quality Department maintains a series of air monitor stations positioned throughout the county that constantly collect air samples and analyzes them for PM10 and PM2.5. This data is then reported back to the EPA to ensure that Maricopa County is meeting the set standard.

One identified source of both PM10 and PM 2.5 is the dust generating activities of the construction industry. Therefore, the County has dedicated itself to monitoring and inspecting the construction industry for adherence to the rules that are aimed at reducing the amount of particulate pollution that get into the air. Their job is to physically go on to construction sites and observe that the rules are being met. Most of the inspections find each site operating in compliance; however, some sites are also found to be operating in violation to the rules. If a site is found to be in violation of the rules the Department may choose to set a monetary fine for such activities.

Many of the violations found by the department are administrative in nature but some involve emitting particulate matter into the air above the set standards. It is hard to believe that in those instances the intention was to create air pollution; but rather simple inattention to proper procedures. When this does happen, practices need to be evaluated and maybe even changed.

Information on how to better control the dust problem can be found at Clean Air Make More or from the Environmental Consultants found at Earthworks Environmental.