CONCENTRATIONS OF CAT AND DUST MITE ALLERGENS IN 93 U.S. OFFICE BUILDINGS

The concentrations of cat (Fel d1) and dust mite (Der f1 and Der p1) allergens were measured in 93 of 100 BASE buildings. Sample mass ranged from 0.005–0.65 g (Median: 0.17 g) and was similar for all floor types and in summer and winter. Fel d1 was detected in 235 samples (94%) [Range: below detection limit (<DL)–19 µg/g; Median: 0.3 µg/g] but exceeded 8 µg/g (a sensitization threshold) in only two buildings. Der f1 and Der p1 were found in 113 (45%) and 128 (51%) samples (Ranges: <DL–53 µg/g and <DL–25 µg/g; Medians: <DL and 0.01 µg/g). Mite allergen exceeded 2 µg/g (a sensitization threshold) in five buildings and 10 µg/g (a symptom threshold) in three of those buildings. Mean Fel d1 concentrations were significantly higher in summer. No consistent patterns were observed between allergen concentrations and summer or winter temperature, summer humidity, building age, cleaning practices, or occupancy