Biocidal sprays are frequently used by consumers in indoor areas to control pests.To obtain data on indoor contaminations, different insecticide aerosol sprays were applied in furnished model rooms (40 m~3). On the one hand, the sprays were used according to the manufacturers' instructions (spraying for about 10-20 sec), and on the other hand under worst-case conditions (spraying for 2 min). Within two weeks, four spray applications with correct use and three worst-case applications were performed. Indoor air was collected a) during the spraying process, b) 2-4 h after spraying (in case of correct use the room was ventilated for 30 min), and c) about two weeks after the last application. The applied sprays contained ⅰ) tetramethrin/d-phenothrin (0.15 g/0.15 g), ⅱ) pyrethrum extract/PBO (0.25 g/lg), and ⅲ) chlorpyrifos/bioallethrin/PBO (0.5 g/0.15 g/n.s.) per 100 g spray. During spraying, concentrations of biocides in the air (mean values from 3 or 4 measurements) ranged from 100-1020 μg/m~3 for correct use (290-6020 μg/m3 for worst case). Highest concentrations of 2510 μg/m~3 (10340 μg/m~3) were measured for the synergist PBO. Two to four h after application, concentrations of the active ingredients in the indoor air were down to 0.1-0.8% (1-11% for worst case). Three weeks after the last application, concentrations between 0.02-1 μg/m3 were measured for both scenarios. To determine the surface load, pads of filter paper were placed horizontally at different positions in the room. The amounts of active ingredients were determined at different times (after first and last applications and about two weeks later). Concentrations varied from 10-480 ng/cm~2 (70-5700 ng/cm~2 for worst case) for biocides and from 300-2260 ng/cm~2 (1000-16500 ng/cm~2 for worst case) for PBO. After 2 weeks, bioallethrin had been degraded, the other biocide concentrations were down to 10-40% (40-70% for worst case). The PBO value remained constant over time.
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