During the summer heat wave of 1988, record ozone concentrations were recorded in the United States. Even Acadia National Park in Maine, and the Shenandoah mountains of Virginia, were affected by dangerous levels of ozone pollution. These rural areas are far removed from industrial regions and polluted cities. The ozone pollution recorded in Acadia most likely originated in New York City. That in Virginia may have migrated from refineries on the Gulf Coast.
Photochemical oxidants are the most significant cause of agricultural loss in the United States.
Their damaging effects on vegetation and crops have been confirmed in the eastern United States, adjacent areas in Canada, and much of Europe.