A new method for collecting airborne allergens

xxBackground: Measurement of airborne allergens has hitherto been done with the use of fixed-location pumps or personal air samplers. Our objective was to find out whether ionizers could be good tools for collecting airborne allergens. As a model we have used cat allergen (Fel d 1). We have compared Fel d 1 levels collected by the ionizer at different time periods, as well as comparing Fel d 1 levels obtained with the ionizer with those of low- and high-volume pumps. Methods: Dust samples from floors and air samples collected with ionizers and pumps, obtained in 31 homes with cat, 23 homes without cats, and 28 day-care centres, were analysed for cat allergen content (Fel d 1) by ELISA. Results: Fel d 1 was present in the reservoir in all homes with cats, ranging from 660 to 375 000 ng/g (GM 75 000) and in the air collected by the ionizer from 2.0 to 204 ng/24 h (GM 19.3). The allergen in homes without cat varied from < 55 to 1800 ng/g (GM 166). Corresponding levels in air were found in two of these homes (2.3 and 7.3 ng/24 h). There was a correlation between the number of cats and the amount of airborne cat allergen (r: 0.47; P < 0.05). The levels in day-care centres were <55 to 3070 ng/g in dust (GM 360) and <1.1 to 7.9 ng/24 h in the air (GM 1.6). We obtained a moderately strong correlation between air and dust samples in homes with cats (r,: 0.64; P < 0.001) and in day-care centres (r,: 0.49; P < 0.05). We found that a collection period of 24 h is preferable for the ionizer. The intrahome reliability coefficient was nearly two times higher for the ionizer (r: 0.69) than the pump (r: 0.39). Conclusions: The ionizer seems to be a good tool for monitoring the environment. It is easy to use and silent and does not disturb the airflow in the room.