State regulators say unhealthy levels of smog were recorded in eastern Iowa this past weekend — the earliest the dirty air has ever been detected in the state. State “Air Quality Bureau” spokesman Brian Button says as many as four counties may’ve been affected.The monitor is located northeast of Cedar Rapids in Coggon, and the smog likely covered Buchanan, Delaware, Jones and Linn Counties. Button says there were several instances of smog recorded in Iowa last year, but not at this time of year. He says they typically don’t detect smog until later in the year.Button says a variety of factors contribute to the formation of smog, such as auto emissions and industrial boilers.Button says Iowa’s string of months with above-normal temperatures has contributed the early presence of smog. He says warm weather increases the likelihood of having the pollutants in the air.Button says the smog probably went unnoticed by most people in eastern Iowa. He says children, asthmatics and others with respiratory problems may have had some trouble breathing.