Toxic volatile organic compounds in 20 homes in Shanghai: Concentrations, inhalation health risks, and the impacts of household air cleaning

Exposure to VOCs causes a variety of adverse health effects, with much of the exposure occurring at home during sleep. The use of an air cleaner maybe an effective and convenient way to reduce associated exposures and health risks. Studies about the impacts of air cleaner on VOCs are limited. The main objective of this paper was to assess the inhalation health risks that toxic VOCs present during nighttime sleep and to estimate the removal effectiveness of an indoor air cleaner on these VOCs. Asthmatic children, who are especially vulnerable to the detrimental effects of air pollutants, were recruited and the VOC concentrations in their bedrooms were measured during two periods - once with a true air cleaner and once with a sham air cleaner. Among the toxic VOCs quantified, formaldehyde, acetaldehyde and toluene had the highest concentrations (median: 18.0, 14.0 and 12.1 μg/m³, respectively) in the bedrooms. Health risk assessments were conducted to identify compounds of greatest concern. During nighttime sleep, 7 VOCs presented inhalation cancer risk above the acceptable risk (1 × 10−6), 4 VOCs exceeded the non-cancer risk threshold (1) in most of the homes tested. The results indicate that the use of an air cleaner in residences may lead to significant reductions in VOC concentrations indoors, but even with this reduction, the associated health risks are still of concern. This study highlights the need for reductions in toxic VOCs at home, points to the imminent need for improvements in control of VOC sources.