The Phoenix area is blessed with mild winters and low humidity. That doesn’t mean, however, that we are without our own issues with our HVAC units and the air that we breath. While surrounded by the open desert air, inside the city and county limits, pollution is high. Phoenix is ranked one of the top 10 worst cities for Ozone pollution and 21st in short-term particle pollution. Pollution in the Phoenix area comes mainly from the burning of fossil fuels, exhaust from vehicles, smoke from fireplaces, ragweed, and other plant pollen.