The Iowa Department of Natural Resources says a large area of eastern Iowa experienced a high level of air pollution in late January. D-N-R Air Information Specialist Brian Button says the pollution was first detected at high levels on January 22nd.They found high levels of small particles of some chemicals in the air. Button says the high levels were found in Black Hawk, Linn, Johnson, Clinton, Scott and Muscatine County. He says it’s likely nine other eastern Iowa counties were impacted by the pollution. Button says it’s rare to see such widespread pollution in the winter. Button says the particles are a mixture of nitrogen oxide and ammonia that’re created by a variety of sources from factories to automobiles.Button says most people probably didn’t notice the particles in the air, but for others with respiratory and heart problems, they could be deadly.Button says monitors indicated the problem on January 22nd, but officials had to take out the monitor filters to physically examine them to confirm the pollution.