A Major Source of Air Pollution: Farms

A new study says that emissions from farms outweigh all other human sources of fine-particulate air pollution in much of the United States, Europe, Russia and China. The culprit: fumes from nitrogen-rich fertilizers and animal waste that combine in the air with industrial emissions to form solid particles—a huge source of disease and death. The good news: if industrial emissions decline in coming decades, as most projections say, fine-particle pollution will go down even if fertilizer use