Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States; Department of Building Science, Tsinghua University, Beijing 100084, China.
Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, United States.
Environ Int. 2021 Feb;147:106342. doi: 10.1016/j.envint.2020.106342. Epub 2021 Jan 2.
Given a large fraction of people's exposure to urban PM occur indoors, reducing indoor PM levels may offer a more feasible and immediate way to save substantial lives and economic losses attributable to PM exposure. We aimed to estimate the premature mortality and economic loss reductions associated with achieving the newly established Chinese indoor air guideline and a few hypothetical indoor PM guideline values. We used outdoor PM concentrations from 1497 monitoring sites in 339 Chinese cities in 2015, coupled with a steady-state mass balance model, to estimate indoor concentrations of outdoor-infiltrated PM. Using province-specific time-activity patterns for urban residents, we estimated outdoor and indoor exposures to PM of outdoor origin. We then proceeded to use localized census-based concentration-response models and the value of statistical life estimates to calculate premature deaths and economic losses attributable to PM exposure across urban China. Finally, we estimated potentially avoidable mortality and corresponding economic losses by meeting the current 24-hour based guideline and various hypothetical indoor limits for PM. In 2015 in urban areas of mainland China, the city-specific annual mean outdoor and indoor PM concentrations ranged 9-108 μg/m and 5-56 μg/m, respectively. Indoor exposures contributed 62%-91% daily and 68%-83% annually to the total time-weighted exposures. The potential reductions in total deaths and economic losses for the scenario in which daily indoor concentrations met the current guideline of 75 μg/m, 37.5 μg/m, and 25 μg/m were 16.9 (95% CI: 0.7-62.1) thousand, 87.7 (95% CI: 9.7-197.7) thousand, and 165.5 (95% CI: 30.8-304.0) thousand, respectively. The corresponding reductions in economic losses were 5.7 (95% CI: 0.2-34.8) billion, 29.4 (95% CI: 2.4-109.6) billion, and 55.2 (95% CI: 7.7-168.0) billion US Dollars, respectively. Deaths and economic losses would be reduced exponentially within the range of 0-75 μg/m for hypothetical indoor PM limits. The findings demonstrate the effectiveness of reducing indoor concentrations of outdoor-originated PM in saving substantial lives and economic losses in China. The analysis provides quantitative evidence to support the implementation of an indoor air quality guideline or standard for PM.
鉴于人们接触城市 PM 的大部分时间都在室内，降低室内 PM 水平可能是一种更可行和更直接的方法，可以避免大量与 PM 暴露相关的生命损失和经济损失。我们旨在估计达到新制定的中国室内空气质量标准和几个假设的室内 PM 标准值所带来的过早死亡和经济损失减少。我们使用了 2015 年来自中国 339 个城市的 1497 个监测站点的室外 PM 浓度，结合稳态质量平衡模型，估算了室外渗透到室内的 PM 浓度。我们使用特定于省份的城市居民活动模式来估计室外和室内对室外来源 PM 的暴露情况。然后，我们使用本地化的基于人口普查的浓度-反应模型和统计生命价值估计来计算中国城市地区与 PM 暴露相关的过早死亡和经济损失。最后，我们通过满足当前基于 24 小时的标准和各种假设的室内 PM 限值，估算了潜在可避免的死亡率和相应的经济损失。2015 年，中国大陆城市地区的特定城市年平均室外和室内 PM 浓度分别为 9-108μg/m 和 5-56μg/m。室内暴露占每日总加权暴露的 62%-91%和每年总加权暴露的 68%-83%。在假设每日室内浓度达到当前 75μg/m、37.5μg/m 和 25μg/m 的标准的情况下，总死亡人数和经济损失的潜在减少量分别为 16.9（95%CI：0.7-62.1）千、87.7（95%CI：9.7-197.7）千和 165.5（95%CI：30.8-304.0）千。相应的经济损失减少额分别为 5.7（95%CI：0.2-34.8）亿美元、29.4（95%CI：2.4-109.6）亿美元和 55.2（95%CI：7.7-168.0）亿美元。在假设的室内 PM 限值 0-75μg/m 的范围内，死亡人数和经济损失将呈指数级减少。研究结果表明，降低室外来源的室内 PM 浓度可以有效地挽救中国的大量生命和经济损失。该分析提供了定量证据，支持实施室内空气质量 PM 标准或标准。
