Particulate Matter
What is Particulate Matter?
Particulate matter (PM) refers to tiny solid particles and liquid droplets suspended in the atmosphere, classified by aerodynamic diameter: PM₁₀ (particles ≤10 µm) and PM₂.₅ (fine particles ≤2.5 µm). PM₂.₅ is of greatest concern for human health because it can penetrate deep into lung tissue and enter the bloodstream, causing respiratory and cardiovascular diseases. Sources include combustion (vehicle exhaust, power plants, wildfires), dust, and secondary formation from gaseous precursors such as SO₂ and NOₓ.
Key Facts
Frequently Asked Questions
Particulate matter (PM) refers to tiny solid particles and liquid droplets suspended in the atmosphere, classified by aerodynamic diameter: PM₁₀ (particles ≤10 µm) and PM₂.₅ (fine particles ≤2.5 µm). PM₂.₅ is of greatest concern for human health because it can penetrate deep into lung tissue and enter the bloodstream, causing respiratory and cardiovascular diseases. Sources include combustion (vehicle exhaust, power plants, wildfires), dust, and secondary formation from gaseous precursors such as SO₂ and NOₓ.