Health benefits and cost of using air purifiers to reduce exposure to ambient fine particulate pollution in China

Understanding the cost-effectiveness of possible interventions to reduce air pollution levels is crucial to developing sustainable mitigation and adaption strategies. Although people spend more than 80% of their time indoors, the role of air purifiers in mitigating personal exposure to indoor PM2.5 of outdoor origin has not yet been quantified, especially in under-developed regions. Here, we performed a comprehensive simulation at the 10 km × 10 km geographical resolution in mainland China to quantify the health benefits and costs of indoor air purification in four intervention scenarios, S1 to S4, where target indoor PM2.5 concentrations were 35, 25, 15, and 10 μg/m3. In intervention scenarios S1 to S4, 93,200 (95% uncertainty interval 78,900–113,600), 115,300 (97,700−140,800), 163,400 (138,300−198,800), and 207,900 (176,300−251,800) deaths that cost 82, 175, 438, and 798 billion Chinese Yuan can be avoided and 93%, 80%, 53%, and 26% of the cities have a positive net monetary benefit. We found that achieving indoor PM2.5 concentration of 35 or 25 μg/m3 using air purifiers is cost-effective at reducing PM2.5 related deaths and PM2.5 concentration of 25 μg/m3 is a suitable indoor PM2.5 target for China. Multifaceted efforts are necessary to ensure equitable access to air purifiers and the knowledge to effectively operate them to make sure the benefits reach the whole population.