5 / 2025-02-27 11:36:29

Residential VOCs from Building Materials: Exposures, Health Risks, and Ambient Hazards

Indoor air quality; Volatile organic compound; Health risk; Ambient; Sustainability

Indoor volatile organic compounds (VOCs) from building materials are a significant concern in China, yet their national indoor exposures, health risks, or impact on the ambient remain underexplored. Here, we integrate emission mechanisms with field measurements of 53 VOC species in 279 residences across nine cities, developing a theoretical-experimental framework linking indoor VOC concentrations to key influencing factors: temperature, humidity, air exchange rate, material loading, recent renovations, and regional variability. Using Monte Carlo simulations, we estimate the average residential concentrations and health risks of the ten most prevalent VOCs across 31 provincial regions. Regional variations are evident: warm, humid regions (e.g., Fujian, Guangdong, Guangxi, Hainan) exhibit higher annual average concentrations of formaldehyde, cumene, toluene, n-propylbenzene, and p-xylene, whereas cold-winter regions (e.g., Sichuan, Chongqing, Zhejiang, Hunan, Jiangxi) show elevated benzene and ethylbenzene levels. Distinct trends emerge for 1,2-dichloropropane, styrene, and 3-chlorotoluene, which peak in severe cold and cold climates (e.g., Inner Mongolia, Jilin, Liaoning, Beijing, Tianjin, Hebei, Xi’an). Seasonal variations further modulate indoor VOC levels, with higher summer concentrations linked to increased temperature and humidity for most species, while 1,2-dichloropropane, benzene, styrene, and 3-chlorotoluene peak in winter. Cancer and non-cancer risk assessments based on incremental lifetime cancer risks (ILCRs) and hazard quotients (HQs) reveal substantial health burdens, particularly in densely populated urban centers. Beyond indoor exposures, residential VOC emissions significantly impact ambient air quality. Among the ten targeted VOC species, formaldehyde emerges as the dominant contributor to total anthropogenic emissions, followed by 1,2-dichloropropane (3.38 Gg/year) and cumene (1.82 Gg/year). Other species, including ethylbenzene, benzene, p-xylene, n-propylbenzene, toluene, styrene, and 3-chlorotoluene, contribute between 0.04 and 1.05 Gg/year. Urban VOC emissions surpass rural emissions, with formaldehyde, cumene, and 1,2-dichloropropane emissions in urban areas being 2.55, 2.44, and 3.03 times higher, respectively. Collectively, formaldehyde, 1,2-dichloropropane, and cumene account for 13.169%, 14.779%, and 2.475% of total anthropogenic VOC emissions, ranking 3rd, 3rd, and 11th among 99 sources. The atmospheric implications of residential VOC emissions are substantial. The formation potential of ambient O3 from building materials reaches 110.562 Gg/year, ranking 35th among the 99 anthropogenic sources and exceeding emissions from nearly half of them. The urban contribution (79.443 Gg/year) is 2.55 times greater than that in rural areas (31.118 Gg/year), with formaldehyde exhibiting the highest O3 formation potential (99.008 Gg/year). Similarly, secondary organic aerosol (SOA) formation from residential VOCs amounts to 0.216 Gg/year, ranking 53rd among anthropogenic sources, surpassing nearly half of them. These findings underscore the urgent need for targeted mitigation strategies to curb VOC emissions from residential environments, safeguarding indoor air quality, minimizing health risks, and reducing broader atmospheric impacts. Strengthening emission regulations and promoting low-emission building materials are critical steps toward reducing VOC exposure and improving overall air quality.