Influence of COVID-19 lockdown overlapping Chinese Spring Festival on household PM(2.5) in rural Chinese homes

During the 2019 novel coronavirus (COVID-19) pandemic, many countries took strong lockdown policy to reduce disease spreading, resulting in mitigating the ambient air pollution due to less traffic and industrial emissions. However, limited studies focused on the household air pollution especially in rural area, the potential risk induced by indoor air pollution exposure was unknown during this period. This field study continuously measured real-time PM(2.5) levels in kitchen, living room, and outdoor in the normal days (Period-1) and the days of COVID-19 lockdown overlapping the Chinese Spring Festival (Period-2) in rural homes in China. The average daily PM(2.5) concentrations increased by 17.4 and 5.1 μg/m(3) in kitchen and living room during Period-2, respectively, which may be due to more fuel consumption for cooking and heating caused by larger family sizes than those during the normal days. The ambient PM(2.5) concentration in rural areas in Period-2 decreased by 6.7 μg/m(3) compared to the Period-1, less than the drop in urban areas (26.8 μg/m(3)). An increase of mass fraction of very fine particles in ambient air was observed during lockdown overlapping annual festival days, which could be explained by the residential solid fuel burning. Due to higher indoor air pollution level and longer time spent in indoor environments, daily personal exposure to PM(2.5) was 134 ± 40 μg/m(3) in Period-2, which was significantly higher than that during in Period-1 (126 ± 27 μg/m(3), p < 0.05). The increase of personal PM(2.5) exposure during Period-2 could potentially have negative impact on human health, indicating further investigations should be performed to estimate the health impact of global COVID-19 lockdown on community, especially in rural homes using solid fuels as the routine fuels.