Work out pm2.5 exposure instantly with clear inputs, formula shown and shareable results.
Inhaled dose is concentration times exposure time times breathing rate. Eight hours at 45 ug/m3 with a 0.9 m3/h resting rate inhales 324 ug of fine particulate - about 0.015 of a cigarette's PM2.5 burden. Exercise multiplies the dose, because ventilation can rise five or tenfold above resting.
Inhaled dose
dose = concentration x hours x breathing rate
Cigarette comparison
roughly 22 mg of PM2.5 per cigarette
Because minute ventilation can rise from 0.5 to over 5 m3/h, so dose scales with it - which is why exercising near traffic is discouraged.
Only as a rough intuition pump. Cigarette smoke differs chemically and is delivered directly to the lung, so health effects are not proportional.