Weather News

Scorching Tri-Cities summer will bring this threat. Here’s how to find out if there’s a warning

The Tri-Cities is in for a hotter than usual summer — and another threat that’s invisible.

Hot, dry days are just the type of weather that leads to high ozone levels in the Tri-Cities air.

This spring the Washington state Department of Ecology is launching an information campaign to warn people about the unusual ozone levels in the Tri-Cities — levels more commonly seen in big cities — and to give information on steps they can take.

It will be working with Washington State University to provide ozone forecasts and issue ozone alerts.

About $46,000 in state funding will be spent on the public awareness campaign.

The state has been concerned since 2015 when Tri-Cities ozone levels were found to be nearly as high as those downwind of Seattle.

A study conducted over the next several years by the state and the Benton Clean Air Agency showed that the readings were no fluke.

The average for 2015 through 2017 exceeded the federal regulatory limit for ozone, which can trigger sanctions from the Environmental Protection Agency.

What’s wrong with ozone

Ozone is good if it is in the Earth’s upper atmosphere, helping shield people from harmful ultraviolet radiation.

But it is harmful if it is near the ground and people are breathing it.

When traffic increases in the Tri-Cities so do harmful ozone levels. The average levels for 2015 through 2017 exceeded the federal regulatory limit for ozone. File Tri-City Herald

It can affect everyone’s health, but some people are more vulnerable. They include physically active people, children, older adults and people with lung disease.

Ozone can inflame and permanently damage lung tissue, according to the Department of Ecology. It also can increase the likelihood of developing pneumonia and bronchitis.

High readings of ozone are most common on hot summer days when there is a light wind from the north or northeast blowing into the Tri-Cities.

Pollutants are blown from the north until the air dams up against the Horse Heaven Hills. There particles bake in the sunshine on hot days, producing ozone, which spreads across the Tri-Cities.

The coming summer is expected to be a hot one in the Pacific Northwest, according to Accuweather. Temperatures could average three to five degrees above normal.

The American Lung Association found that the Tri-Cities had at least 14 days over three years with unhealthy ozone levels. The Department of Ecology estimates it could be six to 10 days a summer.

Steps you can take

If you want to prepare for those hot, high ozone days, you can check the newly launched

It includes a three-day forecast for ozone level in the Tri-Cities and allows residents to sign up for ozone alerts.

Capture ozone forecast.PNG
No ozone troubles now in the Tri-Cities, according to this forecast. But once the hot weather arrives, ozone can reach unhealthy levels. Courtesy Washington State University and Department of Ecology

Current daily information on ozone levels, and also other air pollutants, is available at

People can use the forecast and current data to make plans to stay indoors until temperatures drop and to cut back on strenuous physical activity outdoors.

They also can do their part to keep ozone levels from spiking.

The Tri-City Development Council and Tri-City area local governments are keeping a close eye on ozone levels, knowing that continued high readings could trigger sanctions from the U.S. Environmental Protection Agency.

The sanctions likely would hit the local economy.

They could make getting air quality permits more difficult for new or expanding businesses, or require them to invest in projects that would offset their contribution to the ozone problem.

But the EPA, which averages the highest ozone readings each year, is likely to look more favorably on the Tri-Cities if it already is taking steps to reduce ozone, according to Ecology officials.

Traffic part of Tri-Cities ozone issue

The chemicals that create ozone can come from the exhaust of motor vehicles, a major contributor in the Tri-Cities.

Gasoline vapors. Industry and wildfires also can contribute.

Residents of the Tri-Cities can make small changes on days when ozone levels are predicted to be high to help keep ozone in check.

They could drive less those days, taking the bus or carpooling, and postpone errands. They also should avoid idling their cars.

Plan to gas up vehicles either in advance of a bad day for ozone or in the evening after the weather has cooled.

Put off mowing or using other gasoline-powered equipment either until evening or until another day. Also avoid barbecuing and using aerosols.

Senior staff writer Annette Cary covers Hanford, energy, the environment, science and health for the Tri-City Herald. She’s been a news reporter for more than 30 years in the Pacific Northwest.