SALT LAKE CITY — Three wildfires burning across Northern California coupled with local wildfire activity are swamping much of Utah with haze, driving fine particulate pollution to above normal levels for this time of year.

By late Monday morning, monitoring stations in various parts of the state, including Box Elder and Salt Lake counties, as well as in Roosevelt and Vernal, were recording PM2.5 levels in the teen range, marking moderate pollution.

Bo Call, manager of the Utah Division of Air Quality’s air monitoring center, said typical fine particulate levels for this late in the summer log in below 10 micrograms per cubic meter.

Pollution was in the moderate range and predicted to hover there throughout Monday and into Tuesday morning.

Call said the haze can look much worse than it actually is due to how sunlight refracts the fine particle pollution, which is about 3% the diameter of a human hair.

“If the sun is behind you it will Iook less bad, but if it is to the side of you or in front of you, it will look worse,” Call said.

“Salt Lake County is definitely being impacted,” he said, with the Magna site recording a value of 6.3 micrograms per meter at midnight and climbing to 18.7 micrograms by 11 a.m. Monday.

A monitoring site in Box Elder County was ticking up as well as a Spanish Fork site.

“We are starting to see our instruments show elevated numbers,” he said.

The smoke is blowing into portions of the state from some significant wildfires burning in Northern California. Several wildfires burning in central Utah are also adding to the haze.

Thunderstorm activity predicted to start in Utah Tuesday afternoon and continue into Wednesday presents a mixed bag for the haze, Call said. The storminess could scrub out the air, but also lead to an increase in wildfire activity from lightning strikes.

The Utah Department of Environmental Quality was advising residents that if the smoke becomes too thick, people with existing heart or lung conditions should limit their outdoor activity and physical exertion. Residents can also close their doors and windows to avoid exposure.

Air pollution exposure is linked to increased incidences of cardiac arrest, stroke, as well as declines in cognitive performance.