Outdoor Air Pollution and Health Impacts

Sources of Air Pollution in Washington

The main sources of outdoor air pollution in Washington State are motor vehicles, outdoor burning, and wood smoke. Gas and diesel-powered equipment, some industries and wildfires also contribute to air pollution. Air pollution in your community depends mostly on local sources; however, some types of air pollution can travel many miles such as ozone and smoke from wildfires. Air pollution can vary by time of year depending on weather and seasonal sources such as woodstoves. You can check current air quality conditions and burn bans in your area. Find out more about air quality in the region and sources of air pollution near you from the clean air agency in your area.

Ozone (O3)

  • Ozone is the main component of smog and occurs mostly during the summer.
  • Ground-level ozone is formed in the environment from the reaction of volatile organic compounds (VOCs) and nitrous oxides (NOx) in the presence of heat and sunlight.
  • Ground-level ozone is separate from the ozone layer that protects the earth from UV radiation.

Health effects of ozone: Ozone irritates the respiratory tract when you breathe it. Ozone can cause wheezing and shortness of breath, chest pain; aggravate bronchitis, emphysema and asthma; reduce lung function; and increase susceptibility to respiratory infections.

For more information, see Ground-level Ozone Pollution, EPA. 

Fine Particulate Matter (PM2.5)

PM2.5 refers to airborne particles 2.5 micrometers or smaller in size (PM2.5), and is also called fine particulate matter.

  • PM2.5 causes regional haze that reduces visibility in some areas.
  • Major sources of PM2.5 include vehicle exhaust, power plants, woodstoves, wildfires and some industries.
  • PM2.5 can be formed in the environment from other types of air pollutants including sulfur dioxide (SO2) and nitrogen oxides (NOx).

Health effects: PM2.5 is so small it can be inhaled deep into the lung and can cause a variety of serious health problems. PM2.5 has been linked to decreased lung function, increased respiratory symptoms including asthma attacks, aggravating existing heart disease, nonfatal heart attacks, irregular heartbeat and premature death among people with existing heart and lung conditions.

For more information see: Particulate Matter Pollution, EPA, Air Quality Guide for Particle Pollution, EPA, Particle Pollution, CDC, Health Impacts of Fine Particles in Air, CDC, Summary of Health Research on Ultrafine Particles (PDF). 

Carbon Monoxide (CO)

  • The major sources of carbon monoxide include vehicle exhaust and wood smoke.
  • Carbon monoxide can also be a serious indoor air contaminant. Indoor sources include furnaces or boilers, kerosene heaters, wood-burning stoves and fireplaces, gas ranges, gas-powered appliances and space heaters, improper use of generators and grills inside and improperly vented car exhaust.

Health effects: Carbon monoxide interferes with the body's ability to absorb oxygen into the blood stream. People with existing heart disease are particularly sensitive to health impacts from carbon monoxide. Exposures to carbon monoxide can result in reduced oxygen to the heart and cause chest pain.

For more information see Carbon Monoxide, EPA.

Nitrogen Oxides (NOx)

  • Nitrogen oxides refers to a group of compounds that include nitrogen dioxide (NO2).
  • NOx contribute to the formation of ozone and PM2.5 air pollution.
  • Major sources include vehicle exhaust, power plants (that burn fossil fuel), and non-road equipment including trains, diesel and gas-powered construction equipment and gas-powered lawn and garden equipment.

Health effects: NOx is a respiratory tract irritant and has been associated with asthma attacks and other respiratory problems and increased hospital visits for respiratory conditions.

For more information, see Nitrogen oxides Pollution, EPA.

Sulfur Dioxide (SO2)

  • O2 is a primary component of acid rain.
  • The main sources of SO2 are power plants that burn fossil fuels, refineries and other industries.

Health effects: SO2 can cause respiratory problems including increasing asthma symptoms.

More information: Sulfur dioxide Pollution (U.S. EPA)

Air Toxics (also called Hazardous Air Pollutants)

  • Air toxics consist of 187 pollutants including solvents and other volatile organic chemicals, other industrial chemicals and industrial by-products, combustion products, and metals including mercury.
  • Air Toxics are regulated differently than EPA's six criteria pollutants (PM, O3, NOx, SO2, CO and lead) because they do not impact large regions and come from many different sources.
  • The major sources of air toxics include vehicle emissions, factories, refineries, and power plants.

Health effects: Air Toxics includes a wide range of air pollutants that are linked to cancer and other serious health problems.

For more information, see Hazardous Air Pollutants, EPA and Air Toxics, Department of Ecology.

People Most Affected by Air Pollution

Air pollution can affect everyone, but some groups are especially sensitive. These include:

  • Children.
  • Older adults (over age 65).
  • People with existing health conditions including: respiratory infections, respiratory diseases including asthma and COPD, heart or circulatory disease, diabetes, or a history of stroke.

Check Air Quality in Your Community

  • Check with your local clean air agency for information about air pollution in your area.
  • Check current air quality in your area.
  • Check and follow burn bans for your area.
  • Replace uncertified wood stoves. Uncertified wood stoves are banned in Pierce County.
  • Avoid burning yard waste and other vegetation, especially in urban growth areas where burning is banned.
  • Drive less and don't let your car idle (PDF).
  • Use electric yard equipment instead of gas-powered equipment.

School Recommendations

When air pollution levels are high, see Air Pollution and School Activities Guide (PDF).

More Resources