How human biology and behavior affect indoor air quality

Abstract

People in the United States spend more than 90% of their lives inside buildings or vehicles (1), and yet most research into air pollution focuses on the outdoors. Relatively little is known about what we breathe for most of our lives. HOMEChem researchers took analytical measurements while volunteers carried out typical at-home activities. Here, they measured a wok’s temperature, which affects the chemical emissions. Image credit: Callie Richmond (photographer). The research that has been conducted on indoor air mainly examines chemicals released from building materials and contents. “Because of that work, those emissions have been gradually reduced,” explains Pawel Wargocki, an indoor air scientist at the Technical University of Denmark in Lyngby. But there is growing evidence that everyday activities also pollute indoor air. Cooking, cleaning, and burning candles all contribute to indoor air pollution—and researchers are now finding that a building’s occupants, simply by being present, significantly change the air chemistry inside as well. Our breath creates a plume of hot, moist air full of reactive trace gases, and our skin emits chemicals into the room. The details of human breath and skin emissions have recently been probed in detail, showing for example that our ammonia emissions increase at higher room temperatures and with more exposed skin (2). These insights, say researchers, will support modeling of indoor chemistry and may pave the way for policy changes—such as increased ventilation and more informative cleaning product labels—to clean up the air in our homes. Indoor air is a complex soup of numerous chemical species (3). Gaseous organic compounds emanate from materials, people, and their actions and can rapidly transform into new gases or particles. Cascades of chemical reactions occur both in the air and after species have settled on surfaces. Newly generated species on surfaces often then become airborne. In the …