The Iowa Department of Natural Resources says the warm weather’s led to more bad air in Iowa. D-N-R air quality specialist Brian Button says southeast Iowa experienced unhealthy levels of particulate matter in the air Wednesday, and could today too.Particulate matter refers to microscopic particles in the air that comes from vehicle exhaust, factory smoke and other emissions. Another air pollutant, ozone smog, was detected at close to unhealthy levels earlier in the week in western Iowa. Button says the smog is a little different from particulate matter.Vehicle exhaust, factory and paint emissions, all cook together above an urban area to make ozone. Button says a cold air mass that’s moving into Iowa should help rid the state of the icky air by pushing out the stagnant air that’s caused trouble. Button says the dirty air in eastern Iowa isn’t unique, but the bad air in western Iowa is unusual.Button says the dirty air can be trouble for people with asthma or other breathing problems.