Airborne birch and grass pollen allergens in street-level shops

Polluted urban outdoor air may be enriched with large amounts of submicroni c respirable pollen allergen particles that penetrate into street-level sho ps. The objectives of the study were to map concentrations of birch and gra ss pollen allergens in indoor air of street-level shops and to explore the effect of electrostatic air cleaning under authentic working conditions, in door air samples were collected in May and July 1999 in two shops. Allergen s were quantified by a direct on sampling filter in solution (DOSIS) lumine scence immunoassay. The average concentration of airborne indoor birch poll en allergen in the shop with air cleaning was estimated to be 20 +/- 9 SQ/m (3) (mean +/- SD) compared to 31 +/- 17 SQ/m(3) (mean +/- SD) of that witho ut. The air cleaner reduced the indoor air birch pollen allergen concentrat ion by on average 26 to 48% (P <0.05). Corresponding figures for airborne i ndoor grass pollen allergen concentrations were 14 +/- 7 SQ/m(3) and 17 +/- 8 SQ/m(3), indicating a statistically non-significant (t-test) average 18% reduction of allergen by air cleaning. Excluding two observations with poo r fit to the statistical model a significant (P <0.05) average 27% reductio n was obtained. Substantial amounts of airborne birch and grass pollen alle rgens may occur in street-level shops during flowering seasons.