Air Pollution: Types, Sources, and Health Effects

Particulate Matter (PM) / Aerosols

None (complex mixture)

Lead

Pb

Ozone

O3

Nitrogen Oxides

NO, NO2, NOx

Carbon Oxides

CO, CO2, COx

Sulfur Dioxide

SO2

Volatile Organic Compounds (VOCs)

VOCs (e.g., CH4, Benzene)

Chlorofluorocarbons (CFCs)

CFCs (e.g., CCl3F)

Particulate Matter (PM) / Aerosols

Solid or Liquid

Lead

Solid (condensed particles)

Ozone

Gas

Nitrogen Oxides

Gas

Carbon Oxides

Gas

Sulfur Dioxide

Gas

Volatile Organic Compounds (VOCs)

Gas (or liquid that evaporates easily)

Chlorofluorocarbons (CFCs)

Gas

Particulate Matter (PM) / Aerosols

Wildfires, dust storms, volcanoes, sea spray

Lead

Volcanic emissions, soil erosion (trace amounts)

Ozone

Stratospheric chemical reactions involving UV light

Nitrogen Oxides

Lightning strikes, soil bacteria, forest fires

Carbon Oxides

Volcanoes, forest fires, animal respiration

Sulfur Dioxide

Volcanic eruptions, hot springs

Volatile Organic Compounds (VOCs)

Plant emissions (pine/citrus trees), wetlands

Chlorofluorocarbons (CFCs)

None (Purely human-made)

Particulate Matter (PM) / Aerosols

Fossil fuel combustion, construction, wood burning

Lead

Leaded aviation fuel, metal smelters, battery manufacturing

Ozone

Secondary pollutant (sunlight acting on vehicle emissions)

Nitrogen Oxides

Vehicle exhaust, coal and gas power plants

Carbon Oxides

Burning fossil fuels, deforestation, incomplete combustion

Sulfur Dioxide

Coal-burning power plants, oil refining, metal smelting

Volatile Organic Compounds (VOCs)

Solvents, paints, glues, gasoline evaporation, vehicle exhaust

Chlorofluorocarbons (CFCs)

Old air conditioners, refrigerators, aerosol propellants

Particulate Matter (PM) / Aerosols

Triggers asthma and lung diseases; causes heart attacks; creates atmospheric haze

Lead

Powerful neurotoxin; causes brain damage and learning disabilities in children

Ozone

Inflames airways and triggers asthma; damages plant tissues and reduces crop yields

Nitrogen Oxides

Lung irritant; primary precursor to both photochemical smog and acid rain

Carbon Oxides

CO2 drives global climate change. CO blocks oxygen transport in blood, which can be fatal

Sulfur Dioxide

Respiratory irritant (bronchitis); reacts in air to form acid rain, damaging forests and aquatic life

Volatile Organic Compounds (VOCs)

Precursor to ground-level ozone/smog; causes eye irritation; some (like benzene) are carcinogens

Chlorofluorocarbons (CFCs)

Destroys the stratospheric ozone layer (increasing harmful UV radiation); acts as a potent greenhouse gas