February 2020
Vol 6, Issue 8

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ONLINE COVER Indoor air quality is important to human health, yet the ways in which chemicals interact with indoor surfaces are not fully understood, complicating scientists' understanding of how to protect people from indoor pollutants. To explore the behavior of common household chemicals, Wang et al. measured 19 contaminants (including poisonous isocyanic acid and nitrous acid, a source of hydroxyl free radicals) in a 110-square meter single-story test home. The researchers repeatedly flushed the house with outside air, then observed how rapidly the chemicals reappeared in the air once the doors and windows were closed. They also mopped the house with vinegar solution and sprayed ammonia to alter the surface pH, finding that cleaning with acidic or basic solutions may temporarily increase exposure to certain compounds. Wang et al. found that most of these indoor contaminants reside in walls, carpets, and floors, not in the gas phase as expected. Since they quickly evaporate from surfaces even after vigorous ventilation, exposure may not be easily controlled by airing out the house. [CREDIT: GARY S. SETTLES/SCIENCE SOURCE]