Fracking has led to an increase in truck traffic, one of the reasons for worsening trends on air quality in areas with oil and gas drilling. (AP Photo/Charles Rex Arbogast) By Gunnar W. Schade, Texas A&M University College of Geosciences, for The Conversation Urban air pollution in the U.S.
In many parts of the world, such as the deserts of the Southwest U.S. or in Africa or the Middle East, sandstorms can create havoc with man and machine.