ICE emissions worse in fire smoke ?

[Cosmo Cruz]

Reading about the fires in Canada. Smelling pine since first light...directly under the front.
Wondering if an ICE engine fails EPA smog tests when inhaling this crap?

 

[TahoeMichael]

I don't know, but I'd guess not. The incoming pollutants are a small fraction of what's produced inside the engine. The high combustion temperature and catalytic converter might actually do a decent job of running the incoming pollutants through a secondary combustion that breaks down the incoming pollutants into chemicals less objectionable than what came in. When in doubt, drive an ICE car enough to bring the engine up to full temperature, and then take it to a testing station that will test it before it cools off.