During the 2019 smoke haze episode in Singapore, elevated levels of fine particulate matter (PM_2.5) were observed, deteriorating both ambient and indoor air quality (IAQ). We investigated the mitigation of indoor human exposure to PM_2.5 of outdoor origin under diverse exposure scenarios with and without filtration of PM_2.5 during both hazy and non-hazy days. The key objective of our study was to make a comparative evaluation of the effectiveness of portable air cleaners (PACs) and air conditioning (AC) systems equipped with particle filters in improving IAQ and to assess related long-term carcinogenic and non-carcinogenic health risks. We conducted real-time measurements of PM_2.5, black carbon mass concentrations and particle number concentrations in both indoor and outdoor areas, quantified the relative concentrations of the water-soluble fraction of toxic trace elements in PM_2.5 for health risk assessment, and estimated the levels of thermal comfort. In addition, we calculated the total estimated cost of indoor air pollution control. Our findings suggest that indoor air cleaners are more effective at mitigating human exposure to airborne particles and reducing health risk with less consumption of electricity and better cost-effectiveness compared to AC. This information would be beneficial for public health interventions during major air pollution events.

在2019年新加坡的烟雾霾事件中，观察到细颗粒物（PM _2.5）含量升高，使环境和室内空气质量（IAQ）恶化。我们研究了在雾天和非雾天，在有和没有过滤PM _2.5的情况下，在各种暴露情况下室内人类暴露于室外PM _2.5的缓解情况。我们研究的主要目标是对配备颗粒过滤器的便携式空气净化器（PAC）和空调（AC）系统改善IAQ的有效性进行比较评估，并评估相关的长期致癌和非致癌健康风险。我们对PM _2.5进行了实时测量，室内和室外区域的黑碳质量浓度和颗粒数量浓度，量化了PM _2.5中用于健康风险评估的有毒微量元素的水溶性部分的相对浓度，并估算了热舒适度。此外，我们计算了室内空气污染控制的总估算成本。我们的研究结果表明，与AC相比，室内空气净化器在减轻人体暴露于空气中的颗粒物方面更有效，并且通过减少电力消耗和更好的成本效益来降低健康风险。该信息对于重大空气污染事件中的公共卫生干预措施将是有益的。