PM25-Primary from certain diesel engines

Exhaust from heavy-duty trucks and buses, construction/mining equipment, locomotives, marine vessels, and older diesel generators, especially without particulate filters [1].

Breathing air near busy roads, ports, rail yards, truck depots, or while commuting; outdoor air can leak indoors and add to indoor levels [1][3].

Can trigger asthma and bronchitis, reduce lung function, worsen heart disease, and raise risks of heart attack and stroke; long-term exposure increases lung cancer risk [1][2][4].

Children, older adults, pregnant people, those with asthma/COPD/heart disease, outdoor workers, and residents near traffic corridors and freight hubs [1][3][4].

Check the AQI; time outdoor activity away from rush hours; choose routes away from heavy traffic; use recirculate in cars; keep windows closed and run HEPA air cleaners indoors; support diesel controls and anti-idling [1][3][5].