Atmospheric Pollution
What you must know
Learn the six criteria pollutants (CO, lead, NO₂, ozone, particulates, SO₂), their sources and health effects. Distinguish primary from secondary pollutants (ozone and PAN are secondary). Understand photochemical smog (NOx + VOCs + sunlight) and industrial smog (SO₂ + particulates). Know acid deposition (SO₂ and NOx → sulfuric and nitric acid) and its effects on soils, lakes, and structures. Study stratospheric ozone depletion by CFCs and the Montreal Protocol, and do not confuse it with tropospheric ozone as a pollutant. Understand indoor air pollution (radon, CO, VOCs, asbestos, mold) and thermal inversions that trap pollution.
Traps
- Confusing ozone depletion (stratosphere) with smog (troposphere) - opposite problems.
- Calling ozone a primary pollutant; ground-level ozone is secondary.
- Mixing acid deposition chemistry: it is sulfur and nitrogen oxides, not CO₂.
- Forgetting indoor air can be more polluted than outdoor air.
Worked example / rule of thumb
On a sunny, windless day with heavy traffic, expect high photochemical smog: NOx and VOCs react in sunlight to form ozone. Rule: sunlight + NOx + VOCs + still air = smog.