The heavy haze hanging over Kamloops is setting even air quality experts' tongues wagging for its abnormality.

The levels in Kamloops have been rising since early Sunday morning.

And while some reports stated the smoke was travelling from the Lillooet area where a wildfire has been 100 per cent contained since Friday, provincial air quality meteorologist Ralph Adams said the evenness of the haze and how widespread it is shows it's from much farther away.

"I think after the fact there's going to be some interesting discussions about trajectories," said Adams. "It's unusual to see a haze that's this heavy and lasts this long from distant fires. And why it's arriving here is going to be open for discussions."

Experts estimate fires in Siberia, the Northwest Territories, Alberta and northern California are all contributing to the smoky air.

"In all likelihood, it's a combination of smoke that's sort of swirling around the western half of the continent," said Adams.

Its thickness in Kamloops is similar to the Lower Mainland, Vernon, Williams Lake and Victoria. However, it appears the further north one travels in B.C., the denser it gets.

The air-quality index for Kamloops was at four out of a possible 10 on Monday, but that was due to elevated ozone levels rather than particulate matter in the smoke.

"When we get these very hot days and hot afternoons, we tend to get higher than normal ozone levels," said Adams.

At that level, people with compromised immune systems or medical conditions should avoid strenuous exercise outdoors. The general population is not at risk.

The haze is expected to hang around until weather patterns change.