London School of Hygiene and Tropical Medicine, London, England, United Kingdom.
United States Embassy in Kathmandu, Nepal.
Sci Total Environ. 2021 Jun 10;772:144836. doi: 10.1016/j.scitotenv.2020.144836. Epub 2021 Feb 2.
The 2019 Novel Coronavirus SARS-CoV 2 (COVID-19) pandemic has severely impacted global health, safety, economic development and diplomacy. The government of Nepal issued a lockdown order in the Kathmandu Valley for 80 days from 24 March to 11 June 2020. This paper reports associated changes in ambient PM measured at fixed-site monitors and changes in personal exposure to PM monitored by APT Minima by four American diplomats who completed monitoring before and during lockdown (24 h for each period per person, 192 person-hours in total). Time activities and use of home air pollution mitigation measures (use of room air cleaners (RACs), sealing of homes) were recorded by standardized diary. We compared PM exposure level by microenvironment (home (cooking), home (other activities), at work, commuting, other outdoor environment) in terms of averaged PM concentration and the contribution to cumulative personal exposure (the product of PM concentration and time spent in each microenvironment). Ambient PM measured at fixed-sites in the US Embassy and in Phora Durbar were 38.2% and 46.7% lower than during the corresponding period in 2017-2019. The mean concentration of PM to which US diplomats were exposed was very much lower than the concentrations of ambient levels measured at fixed site monitors in the city both before and during lockdown. Within-person comparisons suggest personal PM exposure was 50.0% to 76.7% lower during lockdown than before it. Time spent outdoors and cooking at home were large contributors to cumulative personal exposure. Low indoor levels of PM were achieved at work and home through use of RACs and measures to seal homes against the ingress of polluted air from outside. Our observations indicate the potential reduction in exposure to PM with large-scale changes to mainly fossil-fuel related emissions sources and through control of indoor environments and activity patterns.
2019 年新型冠状病毒 SARS-CoV-2（COVID-19）大流行严重影响了全球健康、安全、经济发展和外交。尼泊尔政府于 2020 年 3 月 24 日至 6 月 11 日在加德满都谷地发布了为期 80 天的封锁令。本文报告了在封锁期间，通过四名美国外交官在固定监测点测量的环境 PM 和通过 APT Minima 监测的个人 PM 暴露变化情况。这四名外交官在封锁前和封锁期间（每人每时间段 24 小时，共 192 人小时）完成了监测。时间活动和使用家庭空气污染缓解措施（使用室内空气净化器（RAC）、密封房屋）通过标准化日记记录。我们根据平均 PM 浓度和在每个微环境（家庭（烹饪）、家庭（其他活动）、工作、通勤、其他户外环境）中花费的时间来比较微环境中的 PM 暴露水平对个人累积暴露的贡献（PM 浓度与在每个微环境中花费的时间的乘积）。美国大使馆和 Phora Durbar 的固定监测点测量的环境 PM 浓度比 2017-2019 同期分别低 38.2%和 46.7%。美国外交官暴露的 PM 平均浓度远低于城市中固定监测点测量的环境水平浓度。个体内比较表明，与封锁前相比，封锁期间个人 PM 暴露降低了 50.0%至 76.7%。户外活动时间和在家做饭是个人累积暴露的主要因素。在工作和家庭中使用 RAC 和措施密封房屋以防止污染空气从外部进入，可以实现室内 PM 水平低。我们的观察表明，通过主要与化石燃料相关的排放源的大规模变化以及通过控制室内环境和活动模式，PM 暴露可能会降低。
