Indoor air quality and its health effects in offices and school buildings in the Yangtze River Delta

Indoor air quality is closely related to human health, and increasing studies have highlighted that poor indoor air quality presents a threat to occupants' health in office and school buildings. This paper aims to analyze the exposure levels and health effects of indoor air pollutants in office and school buildings in the Yangtze River Delta, China. The published studies from 1980 to 2020 concerning indoor pollutants (including formaldehyde, PM2.5, PM10, CO2, TVOC, benzene, toluene, xylene, ammonia, microbial pollutants, and radon) in this zone were systematically reviewed. The Composite Index Method was used to evaluate indoor air quality, and DALYs (disability-adjusted life years) were evaluated by the IND and ID methods to quantify the health effects of inhaled air pollutants. The review found that PM2.5 concentrations exceeded current standards in China in 57% of the study samples in office buildings, while formaldehyde, benzene, TVOC, and ammonia exceeded existing standards in 60%, 62%, 61%, and 86% of the samples, respectively. In school buildings, 55% and 100% of the samples with the formaldehyde and ammonia concentrations exceeded the limits in standards, respectively. The evaluation of indoor air quality showed that office and school buildings in the Yangtze River Delta were at a medium and light pollution level, respectively. Furthermore, based on the DALYs value, the health risks of studied pollutants were ranked as PM2.5 > formaldehyde > ammonia > benzene > toluene > xylene. This review pointed out that in over half of the studies, the levels of pollutants (PM2.5, formaldehyde, benzene, TVOC, and ammonia) in office and school buildings exceeded the limits set by the current indoor air quality standard. PM2.5 and formaldehyde played important roles in impacting human health. Additionally, the levels of pollution varied among cities, and there were differences in health effects caused by different air pollutants, which should be noticed. This review provides valuable information on the levels and health effects of major pollutants, contributing to the control of main pollutants in school and office buildings.