THE EFFECT OF OUTDOOR FUNGAL SPORE CONCENTRATIONS ON DAILY ASTHMA SEVERITY

The relationship between day-to-day changes in asthma severity and com bined exposures to community air pollutants and aeroallergens remains to be dearly defined. We examined the effects of outdoor air pollutant s, fungi, and pollen on asthma. Twenty-two asthmatics ages 9-46 years were followed for 8 weeks (9 May-3 July 1994) in a semirural Southern California community around the air inversion base elevation (1,200 ft ). Daily diary responses included asthma symptom severity (6 levels), morning and evening peak expiratory flow rates (PEFR), and as-needed b eta-agonist inhaler use. Exposures included 24-hr outdoor concentratio ns of fungi, pollen, and particulate matter with a diameter <10 mu m ( PM10; maximum = 51 mu g/m(3)) and 12-hour day-time personal ozone (O-3 ) measurements (90th percentile = 38 ppb). Random effects longitudinal regression models controlled for autocorrelation and weather. Higher temperatures were strongly protective, probably due to air conditionin g use and diminished indoor allergens during hot, dry periods. Control ling for weather, total fungal spore concentrations were associated wi th all outcomes: per minimum to 90th percentile increase of nearly 4,0 00 spores/m(3), asthma symptom scores increased 0.36 (95% CI, 0.16-0.5 6), inhaler use increased 0.33 puffs (95% CI, -0.02-0.69),and evening PEFR decreased 12.1 l/min (95% CI, -1.8-22.3). These associations were greatly enhanced by examining certain fungal types (e.g., Alternaria, basidiospores, and hyphal fragments) and stratifying on 16 asthmatics allergic to tested deuteromycete fungi. There were bo significant ass ociations to low levels of pollen or O-3, but inhaler use was associat ed with PM10 (0.15 inhaler puffs/10 mu g/m(3); p<0.02). These findings suggest that exposure to fungal spores can adversely effect the daily respiratory status of some asthmatics.