The start of spring also signals the beginning of the smog season in Iowa. Smog is the hazy look the sky gets when warm temperatures cook small particle emissions from vehicles and factories and fumes from paints and chemicals. D-N-R air information specialist Brian Button says smog generally occurs on the edges of the state. He says extreme eastern Iowa and western Iowa have the most smog. He says there’ll occasionally be some smog in in central Iowa. The D-N-R has air monitors out to try and figure out where the smog is developing.He says eastern Iowa is easier to explain as it is closer to the dirtier air of the industrialized east, the population is heavier, as is the industry. Button says it’s they aren’t sure why smog has been a problem in western Iowa.He says they don’t know if the smog is coming in from Omaha and Kansas City, and need to study the issue more. Button says you can view the daily smog levels in Iowa on the D-N-R’s website. He says info from other states is on the E-P-A’s website. He says that information is useful for people who’re traveling and have problems handling dirty air. Button says the smog season in Iowa normally runs from April though October.