Air Purifier Intervention to Remove Indoor PM 2.5 in Urban China: A Cost-Effectiveness and Health Inequality Impact Study.

Using air purifiers is an intervention to reduce exposure to fine particulate matter (PM) for health benefits. We performed a comprehensive simulation in urban China to estimate the cost-effectiveness of long-term use of air purifiers to remove indoor PM from indoor and ambient air pollution in five intervention scenarios (S1-S5), where the indoor PM targets were 35, 25, 15, 10, and 5 μg/m, respectively. In scenarios S1 to S5, 5221 (95% uncertainty interval: 3886-6091), 6178 (4554-7242), 8599 (6255-10,109), 11,006 (7962-13,013), and 14,990 (10,888-17,610) thousand disability-adjusted-life-years (DALYs) can be avoided at the cost of 201 (199-204), 240 (238-243), 364 (360-369), 522 (515-530), and 921 (905-939) billion Chinese Yuan (CNY), respectively. A high disparity in per capita health benefits and costs was observed by city, which expanded with the decrease of the indoor PM target. The net benefits of using purifiers in cities varied across scenarios. Cities with a lower ratio of annual average outdoor PM concentration to gross domestic product (GDP) per capita tended to achieve higher net benefits in the scenario with a lower indoor PM target. Controlling ambient PM pollution and developing the economy can reduce the inequality in air purifier use across China.