Air Quality Program
Air Quality Program Manager
928-269-6669
Environmental Department
Air Quality Program Manager
P.O. Box 99110
Yuma, Arizona 85369-9110
Fax: 928-269-5216
Particulate Matter PM-10
PM-10 is one of six criteria pollutants. Annual and 24-hour ambient air standards for criteria pollutants have been set by the Environmental Protection Agency (EPA). The standards are health-based.
Yuma was classified as a moderate non-attainment area by the Environmental Protection Agency. A State Implementation Plan (SIP) was sent to the EPA in November of 1991 and a revised SIP was sent to EPA in July of 1994. The control measures in this plan reduced the amount of PM-10 emissions significantly from pre-1991 levels. On August 18, 2002, during a dust storm, Yuma exceeded the established 24-hour average for PM-10 (150ug/m3) with an average of 170 ug/m3. Studies showed that one-third of the dust came from man-made activities. The highest dust-generating activity came from on-road travel, the next highest cause was from construction.
To be reclassified as "attainment", an area must meet the ambient air standards for 3 years and develop a plan to demonstrate how they will be able to maintain these standards on a continuing basis.
A Yuma area stakeholders group was formed consisting of state, city, county, tribal, and federal agencies, law enforcement, agriculture, construction, irrigation districts, businesses, and concerned citizens to developed a Natural Events Action Plan (NEAP). This Plan describes how Yuma is going to control man-made PM-10. This will lessen the impacts that naturally occurring dust storms have on our air quality. The Plan also discusses how to teach the public about the health effects of PM-10 and inform them of natural dust events that could cause health problems for people.
Controls were developed to control PM-10. These practices go into effect August 2005.
- Construction site sign ordnance.
- Best Management Practices for agriculture.
- Enforce no trespassing on canal roads and speed limits on dirt roads.
Particulate matter is divided into two types: coarse (PM-10) and fine (PM 2.5). PM-10 is caused by dust, smoke, and soot particles. PM 2.5 is caused by burning wood, diesel and other fuels, smoking, and industrial plants.
Particulate matter causes nose and throat irritation, causes breathing problems and aggravates asthma, bronchitis, and emphysema. It is most harmful to infants and young children, the elderly, and those with heart and lung disease.
Particulate matter can discolor structures, clothes and furniture.
Particulate Matter Size Comparison
Causes of PM-10
Undisturbed desert soil forms crust. It takes a high wind, over 15 miles per hour, to make undisturbed soil become airborne for any distance. When soil is disturbed, it becomes airborne with a much lower wind speed.
The main cause of PM-10 in Yuma is on-road travel. This includes dirt getting on the roads or driveways, falling from undercover loads, and falling from tires or vehicle bodies. When dirt gets onto the roadways, vehicle driving over it breaks it into smaller particles. These small particles can become airborne with very light winds.
The next highest cause is from disturbed soil at construction sites.
Other causes of PM-10 include:
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Travel on unpaved roads
- Travel on canal banks
- Agricultural tilling
- Milling, grinding, rock crushing operations
- Open burning
- Diesel and other exhaust
Imperial County, California is a serious non-attainment area for PM-10. On the CMAGR and Camp Billy Machen road speeds are limited:
- Maximum speed at Camp Billy Machen is 15 mph
- Maximum speed on semi-improved roads is 25 mph
- Maximum speed on unimproved roads is 15 mph
- Maximum speed through a troop area is 10 mph
- Military tactical vehicle during period of training
- The bus has passengers on board
- A bus may idle for 10 minutes while passengers are loading and unloading
- Idling when the vehicle is queuing up
- Idling due mechanical difficulties or adverse weather conditions that the driver has no control over
- Idling during a vehicle inspection to verify the equipment is in good working order
- During testing, maintenance, service, or diagnostic purposes