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Fun with fireworks pushed air quality well into unhealthy categories across multiple Utah counties on the Fourth of July and, in some counties, on multiple occasions throughout the weekend.

Salt Lake County was the hardest-hit area, with concentrations of PM 2.5 — the small particulates generally associated with Utah's wintertime inversions — soaring to 204 micrograms per cubic meter Monday night. That level of pollution would be considered "very unhealthy" and would have been reported as "purple" air quality, according to the air quality index, had it persisted.

The Environmental Protection Agency's standard for particulate pollution is 35 micrograms per cubic meter, but that measurement is averaged over a 24-hour period. Salt Lake County was averaging 34 micrograms per cubic meter Tuesday as a result of Monday night's spike.

But Salt Lake County's Monday night spike was an isolated incident. Other areas saw multiple peaks — in Weber County, for example, PM 2.5 rose to 68 micrograms per cubic meter on Saturday night, then jumped again on July Fourth to 96 micrograms per cubic meter. Smaller spikes also occurred Friday and Sunday nights in that county.

Utah County reported high concentrations of PM 2.5 in the evenings throughout the weekend, reaching the highest point of 45 micrograms per cubic meter late Saturday.

While it's difficult to pinpoint the exact cause of the spikes, Kevin Hart, an environmental scientist for the Utah Division of Air Quality, said the data is typical for this time of year, and most likely associated with fireworks.

"We're pretty much attributing it to different fireworks — city fireworks along with the individual stuff," Hart said."There's been other years where we've had the fireworks going off, and we've hit high values in the evening like that."

The reported values in various counties also coincides with the precise location of the individual monitors, Hart said. Many of the division's monitors are located at schools, where some residents may congregate to light fireworks in parking lots. That could be why some counties, like Salt Lake County — which has a monitor at Hawthorne Elementary in Salt Lake City — reported significantly higher values than other counties, such as Utah County, which has a monitor on property that belongs to the National Guard.

While the pollution was short-lived in this case, it still could have had a negative impact on the health of at-risk populations, said Tiffany Brinton, Salt Lake County Health Department's asthma coordinator. Smoke from fireworks is a common trigger for many individuals with asthma, she said.

People aren't as likely to recognize fireworks as the source of the problem and to consequently avoid them, Brinton said. "Fireworks are not around all the time, and cause people to be caught off guard," she said.

That was the case for South Salt Lake resident Kelly Gregersen. She resorted to using her inhaler twice Monday night, she said, despite sequestering herself indoors and turning off her swamp cooler. It was the first time she's had to use an inhaler twice in one night, she said.

Gregersen said she began to experience respiratory distress just a few years ago, and since then she has learned to associate her episodes with periods of poor air quality. And with the 24th of July still ahead, she said she is concerned that she and others like her will continue to experience symptoms for the rest of the month.

"I'll bet people are suffering this whole month just because people want to light fireworks," she said. "I really don't think that it's fair. I don't think people take into consideration other people."

Gregersen said she thought it would be helpful if Utah were to limit fireworks to the days of July 4 and July 24 exclusively, and possibly even limit the use of fireworks to official city celebrations exclusively.

Otherwise, she said, she might have to consider relocating. "This is really bad," she said. "So bad that I'm thinking about moving."

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