This report presents a survey of the current state of knowledge of the potential impacts of climate change and variability on aeroallergens--pollen, mold, and indoor allergens--in the United States and the allergic diseases associated with them. Allergies are prevalent in the U.S. and impose substantial economic and quality-of-life burdens. A recent nationwide survey reported that 54.6 percent of people in the U.S. test positive for one or more allergens (American Academy of Allergy Asthma and Immunology, 1996-2005).

"August 2008". "EPA/600/R-06/164F" Includes bibliographical references.

Allergies and allergy-related illnesses are widespread in the U.S. and impose substantial economic and quality of life burdens. Changes in climate, including increased CO2 concentrations, could impact the production, distribution, and dispersion of aeroallergens; allergen content; and the growth and distribution of the weeds, grasses, tress, and mold that produce them. While the literature does not provide definitive data or conclusions on how climate change might impact aeroallergens and subsequently allergenic illnesses, some tentative conclusions can be drawn: Pollen production is likely to increase in many parts of the U.S. with the possible exception of the Southeast; Phenologic advance is likely to occur for numerous species of plants, especially trees; There will likely be changes in the distribution of pollen producing species, including the possibility of extinction in some cases; Intercontinental dispersal is possible, facilitating the introduction of new aeroallergens into the U.S.; and Increases in allergen content of some aeroallergens are possible.