After one ozone alert day and exceedance in 2020, the Tulsa metro has turned in three of each so far this year, with more than two months left in the season.
On June 14, 15 and 17, monitoring stations picked up ozone readings above the Environmental Protection Agency standard of 0.071 parts per million, the highest being 0.087.
"The weather patterns really just stalled, stagnated and trapped the stuff that creates ozone in the Tulsa region," said INCOG Air Quality Programs Manager Nancy Graham. "So, the three exceedances are an issue. That means the days were unhealthy, but it is not what the EPA looks at when they're looking at whether or not they put an area into non-attainment or violating the ozone standard."
Ozone standard violations occur when a three-year average of specific readings exceeds the EPA standard. Graham said Tulsa’s average remains below that, but people should pay attention for ozone alert days and take actions like holding off on mowing and pumping gas in the evening on those days.
Graham said a steep drop in travel because of the COVID-19 pandemic helped keep ozone levels down last year.
"And many of the job sites were closed down. So, the emissions just weren't in the air. Even though the weather was quite hot, the emissions weren't there to mix to make that ground-level ozone problem," Graham said.
Ozone forms when heat and sunlight cause chemical reactions between nitrogen oxides and volatile organic compounds, which are in pollutants emitted by cars, refineries and other sources. Breathing in ground-level ozone can cause chest pain, coughing, throat irritation, and congestion. It can also worsen chronic conditions like asthma.