Coarse Particulate Matter (PM10)

PM10 includes road dust, construction dust, agricultural tillage dust, desert dust, pollen, mold spores, sea salt, and coarse industrial particles [1]. Unlike PM2.5, which can travel thousands of miles from its source, PM10 settles out within miles and is most concentrated near its origin — highways, dirt roads, farms, mines, and dry lake beds [2]. The Dust Bowl of the 1930s was an extreme PM10 event that caused 'dust pneumonia' deaths across the Plains states. Today, California's San Joaquin Valley routinely exceeds PM10 standards due to agricultural dust, and desert communities in the Southwest are exposed to natural windblown dust [1]. PM10 was EPA's first particle standard (1987); PM2.5 was added in 1997 after evidence showed smaller particles drove the health effects at lower concentrations [2].

Living near unpaved roads, construction sites, and agricultural fields is the primary exposure scenario [1]. Wind events in arid regions mobilize PM10 from dry soils; communities downwind of tilled fields or disturbed desert soils experience episodic high exposures [2]. Indoor PM10 from vacuuming, sweeping, and resuspension of settled dust is significant. Occupational exposure occurs in mining, quarrying, agriculture, cement manufacturing, and demolition [1]. Road cyclists and runners near construction zones inhale substantial PM10 doses during exertion [2].

PM10 deposits in the upper airways and bronchi, impairing mucociliary clearance and triggering inflammatory responses that worsen asthma, bronchitis, and COPD [1]. Valles Caldera desert dust carries biological material — spores of Coccidioides (causing Valley Fever), bacteria, and allergens — embedded in PM10 that add infectious and allergenic burden beyond the particle itself [2]. Epidemiological studies show PM10 elevations on dust storm days increase emergency room visits for asthma and COPD within 24-48 hours. Occupational PM10 from mining causes pneumoconiosis; construction dust (including crystalline silica-containing PM10) causes silicosis [1].

People with asthma and COPD experience exacerbations during high-PM10 events [1]. Agricultural workers, miners, quarry workers, and demolition workers with chronic high-dose occupational PM10 exposure develop occupational lung disease [2]. Children in farming communities have higher rates of respiratory symptoms on high-dust days. Desert and semi-arid region residents face both mineral dust and Coccidioides spore exposure [1]. Construction and renovation workers often work without adequate dust controls, particularly in smaller operations [2].

1. On high-PM10 days (AQI elevated, visible dust), wear an N95 or P100 respirator for outdoor activity — surgical and cloth masks provide inadequate PM10 filtration for high-exposure situations [1]. 2. Keep windows closed on windy days in agricultural or desert areas to reduce indoor infiltration. 3. Vacuum with a HEPA-filter vacuum rather than sweeping to reduce PM10 resuspension from floors [2]. 4. If you work in dusty occupations, advocate for wet-suppression methods, enclosed cabs with filtered air, and dust extraction at point sources. 5. After dust storms, avoid areas until settled [1]. 6. In agricultural areas, drive slowly on dirt roads to minimize dust generation for yourself and neighbors [2].