Puget Sound Clean Air Agency

Where Does Pollution Come From?

FY2006 Sources of Pollution chart


Click on the chart to view a larger version in a new window.

Business and industry used to be the main source of air pollution, but regulated and voluntary efforts have greatly reduced pollution from these sources. The bulk of today’s air pollution is actually a result of our individual activities – exhaust from vehicles, yard and recreational equipment, and smoke from our chimneys and burn piles.

The following table summarizes the sources of the criteria air pollutants, their health and environmental effects, and steps you can take to reduce, or better yet, prevent pollution. You’ll note for the purposes of this chart that particulate matter has been broken down into two sub-categories.

Pollutant Sources Effects Prevention & Control
Fine Particulate Matter (PM2.5)
  • Burning in fireplaces & woodstoves, land-clearing, yard waste.
  • Exhaust from cars, trucks, buses and combustion sources.
  • Formed in the atmosphere from chemical reactions of pollutant gases.
  • Linked to respiratory disease, decreased lung function, asthma attacks, heart attacks and premature death.Reduced visibility.
  • Reduce mobile and diesel emissions.
  • Cleaner winter burning and heating practices.
  • Enforce winter burn bans.
  • Reduce use of uncertified woodstoves.
  • Conserve energy.
Particulate Matter (PM10)
  • Road dust.
  • Windblown dust and construction.
  • Also formed from other pollutants.
  • Linked to respiratory disease, decreased lung function, cancer, and premature death.
  • Reduced visibility.
  • Control dust sources.
  • Reduce wood burning in woodstoves and fireplaces.
  • Conserve energy.
Ozone (03)
  • Formed when reactive organic gases and nitrogen oxides react with sunlight.
  • Sources include emissions from gasoline & diesel vehicles, marine vessels, and evaporative and other sources, such as solvents, degreasing and painting operations, outdoor burning and large industrial facilities.
  • Linked to respiratory irritation, decreased lung function, weakened immune systems and tissue damage.
  • Reduction of motor vehicle emissions through emission standards, reformulated fuels, gas station vapor recovery compliance.
  • Smog Watches to encourage reduction of pollutant emitting activities on high ozone days.
  • Reduced vehicle use.
Carbon Monoxide (CO)
  • On-road gasoline vehicles, non-road vehicles, on-road diesel vehicles and marine vessels and aircraft.
  • Burning in woodstoves, fireplaces and outdoors.
  • Linked to cardiovascular and respiratory problems, headaches, chest pain, impaired vision, and reduced mental alertness.
  • Control motor vehicle and industrial emissions.
  • Use oxygenated gasoline during winter months.
  • Conserve energy.
Sulfur Dioxide (SO2)
  • Coal or oil burning.
  • Diesel engines.
  • Linked to a variety of respiratory diseases and breathing problems.
  • Reduce the use of high sulfur fuels.
  • Metal smelters.
  • Leaded gasoline.
  • Linked to learning disabilities, brain and kidney damage.
  • Control metal smelters.
  • Replace leaded paint with non-lead substitutes.
Nitrogen Dioxide (NO2)
  • On-road gasoline vehicles, non-road vehicles, on-road diesel vehicles and marine vessels and aircraft.
  • Burning in woodstoves, fireplaces and outdoors.
  • Lung irritation and damage.
  • Reacts in the atmosphere to form ozone and acid rain.
  • Control motor vehicle and industrial combustion emissions.
  • Reduce wood burning.