Predicting onset and severity of pollen seasons in a semi-arid climate

Abstract

Rationale Prediction of airborne pollen may be useful in the management of allergic airway disease. Methods Pollen was collected continuously over a seven year period in Tucson, Arizona, using a 7-day recording volumetric Burkard spore trap. Meteorologic data available from a site in central Tucson were studied in the year before pollen collection and during the years of collection, including temperature variables, solar radiation, rainfall, and relative humidity. Olea (olive), Ambrosia (ragweeds) and Poaceae (grasses) were studied. Results There was a positive correlation between increased rain in February and Olea pollen numbers in the following pollen season (p=0.02). Minimum temperatures between January 15th and February 15th correlated with reduced total annual Olea pollen counts (p=0.02). High accumulated solar radiation and low rainfall in the 2 months before the Ambrosia season correlated with delayed onset of the season ( p<0.001). Total Ambrosia pollen count correlated strongly with high rainfall in the preceding two months ( p<0.001). Grass pollen in Tucson routinely peaks in spring and again in late summer. The start of the first season correlated with total amount of pre-seasonal rain and accumulated solar radiation. The amount of grass pollen released in the second season correlated strongly with monsoonal rainfall (p=0.001). Conclusion The onset and extent of the season of certain allergenic pollen types may be predicted by climatic variables.