The disease burden related to time-weighted PM2.5 exposure in China and the potential health benefits of the national standards for indoor air quality: A modeling study

PM2.5 pollution is a major environmental risk factor, causing substantial disease burden and economic loss. The Indoor Air Quality Standard (GB/T 18,883-2022) with the targeted daily average indoor PM2.5 concentration (50 mu g/m3) has just been issued in China. To determine whether this new guideline can provide sufficient protection, we evaluate the health and economic burden attributable to the time-weighted average PM2.5 exposure under the three scenarios related to this guideline, using the Global Burden of Disease (GBD) and Willingness-to-pay (WTP) method based on the disease mortality rate, exposure-response relationship and socio economic data. The annual mean time-weighted average PM2.5 (TWPM) concentration in 2020 under the Unchanged, Indoor Air Policy (IAP), Indoor and Outdoor Air Policy (IOAP) scenario were 22.4, 21.7 and 17.5 mu g/m3 in China, respectively. Compared with the Unchanged scenario, in which the TWPM-related premature deaths and economic burden were estimated to be 1.22 million and 3.35 trillion RMB Yuan, 0.03 million premature deaths and 8.74 billion RMB Yuan were estimated to be avoided in the IAP scenario; 0.18 million premature deaths and 58.58 billion RMB Yuan in the IOAP scenario. The greater TWPM-related mortality occurred in the heavily polluted and densely populated region, such as the Beijing-Tianjin-Hebei, Fenwei Plain and Sichuan and Chongqing region. The TWPM-related disease burden in China remained obvious even if China complies with the new standard. In comparison to simply improving indoor air quality, boosting both indoor and outdoor air quality may achieve more significant health and economic benefits. Therefore, with the goal to improve indoor air quality, it is still necessary to strengthen outdoor ambient air quality improvement actions.