It’s not just smoke that’s making Tri-City air worse than you realize

Tri-City air was doubly bad on Thursday.

People could see the gray tint to the air caused by smoke particles, but the high ozone levels were not as visible.

Monitors showed that each were present in high enough quantities alone to make the air unhealthy to breathe.

Everyone was again advised by the Washington State Department of Ecology to stay indoors and avoid strenuous activities both inside and out.

The National Weather Service said the air quality in Washington state was the worst in the nation Wednesday, but some parts of the state — just not the Tri-Cities — saw some improvement on Thursday.

In Chelan and Wenatchee the air quality reached the hazardous level on Wednesday, prompting Chelan County officials to distribute masks. Air quality there improved from “hazardous” to “very unhealthy” on Thursday.

In the Puget Sound, marine air moved in to improve air quality to ratings as good as “moderate” on Thursday.

But there’s no clear forecast for when air quality might improve for the Tri-Cities.

On a positive note, thunderstorms passing through Oregon south of Pendleton on Thursday night might create some mixing and dilution of the smoke-filled air that’s been trapped over the region, according to the weather service.

But in the Tri-Cities, where the most that was expected Thursday night and Friday morning was the distant boom of thunder, the storm system may be too weak to make much difference in the air quality.

On a more negative note, possible winds from the north on Sunday could bring new smoke to Washington, according to the Department of Ecology.

Fires are burning in the Cascade Mountains and British Columbia. More than 1,800 wildfires have been recorded in British Columbia during the current fire season, and 13 large wildfires have burned more than 211 square miles in Washington state.

Smoke not only fouls the air, but can also add to high levels of ozone.

In the Tri-Cities, pollution from sources that include traffic combine to bake in the sun to form ozone, particularly when a light northern breeze causes air to pool along the Horse Heaven Hills.

The weather service continues to predict widespread haze over the Tri-Cities through Wednesday.

It has issued an air quality alert for Benton and Franklin counties through noon Friday. It will reassess conditions Friday morning and decide whether to extend the alert.

Everyone should take care when air quality is rated as unhealthy, but problems may be more severe for infants, children, older adults and pregnant women, according to the Department of Ecology.

People with heart and lung disease, or chronic illnesses such as diabetes, also are at increased risk.

High ozone levels, which are more typical for metropolitan areas, can aggravate asthma, inflame and scar lung tissue, and make people more susceptible to bronchitis and pneumonia.

The Associated Press contributed to this report.