Golden fall colors in a vineyard with deep blue skies and clouds

Air Pollutants and Trends

Windblown Dust in Benton County

The Tri-Cities are located in the most arid part of Washington State. Learn how windblown dust affects our County.

What are the pollutants measured in Benton County?

There are six common air pollutants (also known as “criteria air pollutants”) established by the  Environmental Protection Agency (EPA) in accordance with the Clean Air Act.  In Benton County, we currently measure three primary air pollutants:  fine and coarse particulate matter (PM2.5 and PM10) and ground-level Ozone (O3).

Particulate Matter

What is Particulate Matter (PM)?

“Particulate matter,” also known as particle pollution or PM, is a complex mixture of extremely small particles and liquid droplets. Particle pollution is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

Where does Particulate Matter come from?

In the western United States, there are sources of PM in both urban and rural areas, major sources include:

  • Activity-related and wind blown dust from construction and agriculture
  • Windblown dust from open lands
  • Outdoor and agricultural burning
  • Wood burning stoves and fireplaces
  • Wildfires
  • Industrial sources
  • Motor vehicles

How can PM affect your health?

The size of particles is directly linked to their potential for causing health problems. EPA is concerned about particles that are 10 micrometers in diameter or smaller because those are the particles that generally pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.  EPA groups particulate pollution into two categories:

  • “Inhalable coarse particles,” such as those found near roadways and dusty industries, are larger than 2.5 micrometers and smaller than 10 micrometers in diameter.
  • Fine particles,” such as those found in smoke and haze, are 2.5 micrometers in diameter and smaller. These particles can be directly emitted from sources such as forest fires, or they can form when gases emitted from power plants, industries and automobiles react in the air. 
PM 2.5 Scale Graphic in comparison with Human Hair

What are the six criteria pollutants?

 The Clean Air Act requires EPA to set National Ambient Air Quality Standards for six commonly found air pollutants known as criteria air pollutants.  Those criteria pollutants are:

  • Particulate Matter
  • Carbon Monoxide
  • Sulfur Dioxide
  • Nitrogen Dioxide
  • Ozone
  • Lead

How does Benton County’s air quality compare with other areas?

Compared to other urban areas in Washington State, Benton County has some of the cleanest air over the majority of the year. Our average pollution levels are well below the national average. However, on occasion, Benton County does have problems with particulate matter pollutants.  

What can I do to reduce PM in Benton County?

  • Always check for burn restrictions before starting any fire.
  • Heat with wood? Burn wisely by using only dry, seasoned firewood and providing plenty of air to avoid a smoky, smoldering fire. Always check burning conditions before you start your fire. More wood heating information.
  • Use a broom instead of a leaf blower to clean sidewalks.
  • Keep the dust down. If you have to drive on an unpaved road, please travel slowly. 
  • Indoor air quality can be affected by particles – learn ways to reduce particles in your home and improve indoor air quality. EPA’s Indoor Air Quality webpage. 


What is Ozone?  Where does it come from?

Ozone can be found in two locations – in the Earth’s upper atmosphere where it protects us from UV radiation. That same ozone at the Earth’s surface is referred to as ground-level ozone. It is a harmful air pollutant that poses a risk to human, animal and plant life. 

Ground-level ozone is formed as a result of photo-chemical reactions between nitrogen oxides and volatile organic compounds in the presence of sunlight and heat. Ozone is only a concern during the hot, summer months when levels can pose a health concern.

Ozone-forming emissions come from many sources including motor vehicles, industrial solvents, gasoline refueling, gasoline-powered yard equipment, auto body paint shops, and consumer products such as charcoal lighter fluid, paints, etc.

How does Ozone affect our health?

Even at low concentrations, ozone causes respiratory problems and aggravates asthma in children. People with respiratory diseases and those who work or exercise outside should limit their time outdoors on hot, sunny days when ozone levels are likely to be elevated.

Children are at higher risk from exposure to ozone because they are often active outside during the summer and their lungs are not fully developed. Long-term exposure to ozone may lead to premature aging of the lungs and chronic respiratory illnesses. 

What can you do to help reduce Ozone?

  •  Reduce car trips by combining errands. Walk, bicycle or ride the bus once a week, instead of driving alone
  • Refuel in the evening. This keeps ozone-forming vapors out of the air during the heat of the day
  • Hold off using gas-powered lawn equipment until evening
  • Use manual or electric yard and garden tools instead of gas-powered tools
  • If you use a charcoal barbecue, start it with an electric probe instead of lighter fluid
  • Use low VOC paints and solvents