State officials issued what amounted to smog alerts for northeast Iowa this weekend. Todd Russell of the Iowa Department of Natural Resources says when very stagnant air masses settle in, a few days before an approaching storm front, "the pollution just can’t disperse." This isn’t the first time such air quality alerts have been issued by the D.N.R. during an Iowa winter. It happened on Groundhog’s Day last February and during this past December.
Russell says it’s mainly because the federal Environmental Protection Agency changed air quality standards in November of 2006, asking state agencies that monitor air quality to issue alerts when air pollutants exceed certain levels. "We had 44 total excedences in 2007, but in reality it’s because the previous (EPA) standard was 65 micrograms per cubic meter and it dropped to 35 micrograms per cubic meter," Russell says.
There were several instances in which air quality monitors around the state registered pollutant levels above the E.P.A. standards this weekend. Davenport and Cedar Rapids were among the areas where the air quality dipped below the federal standards. Russell of the D.N.R. says it happened because there was a sort of "cap" over the state this weekend.
"Where we have warm air over the top of the cold air, it holds the cold air down and in place so that pollutants can’t disperse," Russell says. "And also the winds are typically light in those type of conditions." There’s a map on-line showing which parts of the country are considered too smoggy.