If you find yourself in a cloud along an Iowa highway, it may not be weather. With spring planting time, DNR air-quality specialist Brian Button says it’s pure dirt, but he adds the blowing topsoil is not a serious health hazard. The particles are large and easily screened out. While they may not harm your lungs, the dust clouds can be a headache for drivers. Button says when farmers do fieldwork and the wind is high, it can stop traffic. He says there’s no lasting harm done even if you drive through a cloud of dust raised by a tractor in a dry field.The soil’s large particles will settle out of the air quickly. It’s been a dry spring in most of Iowa, but Button says a rainy day or two will end the dust problem.