Comparison of electrostatic collection and liquid impinging methods when collecting airborne house dust allergens, endotoxin and (1,3)-β-d-glucans

The use of electrostatic collection was investigated in quantifying airborne environmental allergens and toxins. The experiments were conducted with two 96-well plates filled with water and placed into the electrostatic sampler designed in this study. The combinations of different electrostatic fields: 0.63, 1.25 kV/cm, and different sampling flow rates: 5, 12.5 L/min, were tested with the electrostatic sampler. As a reference, a BioSampler operating at 12.5 L/min was simultaneously placed in the same environments. The sampling lasted for 40 min both for electrostatic sampler and the BioSampler in each test. House dust allergens, endotoxin and (1,3)-β-d-glucans in the air samples collected were analyzed using enzyme-linked immunosorbent assay (ELISA) and Limulus amebocyte lysate (LAL) method, respectively. The entire experiments were conducted both in office environment and hotel rooms.The concentrations of airborne allergens (Der p 1 and Der f 1) and toxins (endotoxin and (1,3)-β-d-glucans) obtained by the electrostatic sampler were shown significantly higher than those by the BioSampler in most cases. Paired t-tests (n=9) indicated that the sampling difference was statistically significant (p-value <0.05). For allergens, the concentration ratio was up to 5.6, and for toxins the concentration ratio was up to 10.8 when the electrostatic sampler was operated at 1.25 kV/cm and 5 L/min. In general, the concentration ratio decreased for both allergens and toxins when the electrostatic field strength decreased or when the sampling flow rate increased for the electrostatic sampler. Paired t-tests (n=9) also indicated there were statistically significant effects of electrostatic field strength and the sampling flow rates on the performance of the electrostatic sampler when collecting the airborne allergens and toxins.This study presented an airborne environmental allergen and toxin monitoring technology, which holds broad promise for detecting and quantifying low level environmental allergen and toxins.