The Tri-Cities has a big city problem.
After finding unhealthy ozone levels in the Tri-Cities air in 2015 that were nearly as high as those downwind of Seattle, the Washington Department of Ecology launched a study with support from the Benton Clean Air Agency.
The results are in — and the 2015 ozone levels were no fluke.
The average for 2015 through 2017 exceeded the federal regulatory limit for ozone, which could trigger sanctions from the Environmental Protection Agency.
Ozone in the Earth’s upper atmosphere is good, shielding people from harmful ultraviolet radiation.
But high levels near the ground are a health hazard. Ozone can aggravate asthma, inflame and scar lung tissue, and make people more susceptible to bronchitis and pneumonia.
Children, the elderly, people with lung disease and those who work hard or exercise outdoors are most at risk.
The sanctions 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.
The Department of Ecology and the Benton Clean Air Agency have just started work with local governments to find ways to reduce ozone.
Size makes us unique
Among the first steps is looking at what other communities have done.
But there are not many communities in the nation the size of the Tri-Cities that have had to address an ozone problem, said Ranil Dhammapala, atmospheric scientist for the Department of Ecology.
Usually high ozone levels are found downwind of large cities like Seattle, Portland and San Francisco, he said.
The Ecology study found no single cause, no “smoking gun”, that could be easily addressed to reduce ozone levels in the Tri-Cities.
Our study found that high ozone concentrations in the Tri-Cities are not caused by a single pollutant or source.
Washington state Department of Ecology
Instead, the area seems to have just the perfect storm of conditions to create ozone, the study found.
Three things are needed to create ozone: nitrogen oxide, volatile organic compounds and the right weather. When the two types of pollutants mix and they are baked in sunlight on hot days, you get ozone.
A buildup of ozone is almost guaranteed under the right conditions, according to a presentation Dhammapala gave to representatives of Tri-City area governments Thursday.
A constant source of the two pollutants, hot weather and a light breeze from the north will do it.
The breeze carries the pollutants in the air until they dam up against the Horse Heaven Hills, allowing the ozone to “cook.”
Nitrogen oxide and volatile organic compounds can come from industrial facilities, electric utilities, gasoline vapors, chemical solvents and the exhaust of motor vehicles.
The state study found ozone spiked during Water Follies, when wildfire smoke blew into the Tri-Cities and on hot days with a very light breeze.
Trees also can play a role in the creation of ozone by releasing a volatile organic compound. Eastern Washington’s shrub steppe landscape is not known for its trees, but the area does have tree farms.
Though there isn’t one source in the Tri-Cities, the pollutants are present in just the right proportions to efficiently create ozone, Dhammapala said.
The recently completed study found ozone spiked when there was smoke from wildfires and also when extra traffic for the Water Follies boat races clogged the roads. Ozone also spiked during a period of high temperatures, low winds and clear skies.
The Department of Ecology has observed that ozone tends to drop on the weekends, likely because of less emissions from workday commuters.
A spike can be seen on weekdays at rush hour, said Robin Priddy, executive director of the Benton Clean Air Agency.
The question now is how to reduce ozone levels.
Who fixes it matters
Although technically the Tri-Cities is out of compliance with federal regulations, it won’t be legally noncompliant until the EPA next reconsiders its designation for the area.
If that happens on the schedule historically used, the EPA will reconsider whether the Tri-Cities is in compliance with ozone levels in 2022.
However, it is not required to wait and can redesignate at any time if there is a concern.
The Tri-Cities would likely be considered only marginally out of compliance, if ozone levels do not continue to increase, and could be given three years to correct the situation before sanctions would be imposed.
The solution for the Tri-Cities ozone issue needs to be local, rather than coming from the state, Dhammapala said.
But it could include public information campaigns or appeals to the public to reduce emissions of the chemicals when hot weather is forecast that will increase ozone levels.
Not idling cars, mowing lawns after the weather cools in the evenings and not filling cars with gas on hot days can help reduce the creation of ozone.
Carpooling, driving less and turning a car off, rather than letting them idle, are among obvious ways to reduce ozone.
Summertime activities like mowing the lawn and barbecuing also increase ozone. Residents may consider passing on those activities on the hottest summer days.
They also can use propane rather than charcoal to barbecue, and use an electric mower or mow in the evening.
Gasoline fumes that escape when a car is filled, and some kinds of painting, also can contribute to ozone, particularly when done on hot days.