If approved, many other areas of the country would have to institute pollution-fighting measures. Right now, Michigan is within the 120 ppb standard, but that could change if the new standard took effect. Once the eight-hour standard is finalized, we'll be looking at upwind sources again. When the Lake Michigan region is on the backside of a high pressure system moving toward the east, ozone concentrations can spike. That's because in those situations, wind tends to blow in from the south, bringing humidity and ozone along for the ride.
Wind also can curl around and bring in ozone from the Ohio Valley.
Yet it would be overly simplistic to say that Wisconsin imports all, or even most, of its summer air problems, said Lloyd Eagan, chief of the Wisconsin DNR's air management bureau. The plumes of pollution from elsewhere do add up and affect us. But what we do at home is the key. Take Door County, for example. The slender peninsula juts out into Lake Michigan and harbors sailboats, not smokestacks.