Here's what happens when one very dirty diesel water delivery truck drives past a PurpleAir sensor. Note the spike and relatively higher level of PM2.5 compared to other sensors in the area. The increase in pollution is still a fraction of what wood burning stoves and fireplaces generate, and the diesel pollution dropped in a few minutes. We still need to work on replacing such polluters since air quality is the biggest environmental health risk of our times. Air pollution is also the main and likely only driver of climate change.