Air Purifier Intervention to Remove Indoor PM_2.5 in Urban China: A Cost-Effectiveness and Health Inequality Impact Study

Abstract

Using air purifiers is an intervention to reduce exposure to fine particulate matter (PM2.5) 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 PM2.5 from indoor and ambient air pollution in five intervention scenarios (S1–S5), where the indoor PM2.5 targets were 35, 25, 15, 10, and 5 μg/m3, 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 PM2.5 target. The net benefits of using purifiers in cities varied across scenarios. Cities with a lower ratio of annual average outdoor PM2.5 concentration to gross domestic product (GDP) per capita tended to achieve higher net benefits in the scenario with a lower indoor PM2.5 target. Controlling ambient PM2.5 pollution and developing the economy can reduce the inequality in air purifier use across China.

China’s public health initiatives for climate change adaptation

“… 79 , 80 However, owing to difference in the socioeconomic resources, weather conditions, and air quality in different regions of China, the health benefits and cost-effectiveness of using air purifiers to remove indoor fine particulate matter are very different. 81 , 82 Modeling studies show that in Chinese cities where the ratio of average annual outdoor PM 2.5 concentration to GDP per capita is low, greater net benefits are derived from using air purifiers to achieve lower indoor PM 2.5 targets. Specifically, 89 cities with the lowest such ratios reaped the most benefits when air purifiers reduced indoor PM 2.5 levels to the WHO AQG 2021 standard of 5 μg/m3.…”

“…Addressing this disparity necessitates advancing sustainable economic growth and prioritizing air quality, especially in cities that are economically lagging yet highly polluted. 82 …”

Exposure to indoor and outdoor air pollution in schools in Africa: Current status, knowledge gaps, and a call to action

“… Current evidence indicates that the use of commercial air purifiers in a school classroom reduced aerosol concentration by 90% just during first 30min of its operation [ 80 ]. Thus, air purifiers are likely effective and may be affordable options [ 81 ]. Similarly, face masks (N95), [ 82 , 83 ] may be options in African schools to reduce children's exposure (i.e., reducing indoor air pollution levels below WHO guidelines and reducing airborne transmission risk of Covid-19) [ 84 ].…”

Indoor Emissions Contributed the Majority of Ultrafine Particles in Chinese Urban Residences

“…To collect a large enough sample size, a Monte Carlo simulation is conducted, relying on repeated random sampling, , to obtain the statistical properties of a phenomenon, which is the source-specific contributions to indoor UFPs in this study. The Monte Carlo method has been applied in previous studies for various applications, such as building energy, optimization of total corneal illuminance, particle penetration, particle deposition on heat exchangers, quanta emission rates of SARS-CoV-2, as well as assessments of indoor air pollutant concentrations and human exposure. − Given that the dynamic mechanism of UFPs differs from PM 2.5 , ozone, nitrogen dioxide, and semivolatile organic compounds, the development of a Monte Carlo Simulation specifically for residential UFP concentrations remains to be established. In this study, the probabilistic distribution of source contributions in Chinese residences was estimated, starting from a source-specific, time-dependent UFP concentration model via Monte Carlo simulation.…”