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1.
Environmental Research Letters ; 16(9), 2021.
Article in English | ProQuest Central | ID: covidwho-1370345

ABSTRACT

Air pollution exposure depends not only on outdoor but also on indoor air quality and human activities. The outbreak of coronavirus in 2019 occurred close to the Spring Festival in China, when many rural-to-urban workers moved to their hometowns, resulting in increased household (HH) consumption of solid fuels for space heating in the rural north. In this study, field measurements of HH PM2.5 (particulate matter with an aerodynamic size ⩽2.5 μm) from a rural village were performed to evaluate changes in indoor, outdoor, and total exposure during the quarantine. Both indoor and outdoor PM2.5 were, as expected, higher during the heating period than during the non-heating period, resulting in much more exposure during the heating season. Indoor exposure accounted for up to 87% and 95% of the total PM2.5 exposure during the non-heating and heating periods, respectively. The contributions of indoor exposure associated with internal sources were 46% and 66%, respectively. Indoor coal combustion resulted in an increment of about 62 ± 12 μg m−3 in indoor PM2.5 exposure. Due to the quarantine, the indoor-originated PM2.5 exposure increased by 4 μg m−3 compared to that during the heating period before the lockdown. In comparison with the exposure before the quarantine during the heating period, the outdoor exposure decreased by 5 μg m−3 during the quarantine, which was mainly attributable to much less time spent outdoors, although the outdoor PM2.5 levels increased from 86 ± 49 μg m−3 to 104 ± 85 μg m−3. However, the overall exposure increased by 13 μg m−3 during the quarantine, resulting from the changes in outdoor exposure (−5 μg m−3), outdoor-originated indoor PM2.5 exposure (+9 μg m−3), PM2.5 from indoor sources before the quarantine (+5 μg m−3), and quarantine-induced indoor PM2.5 increments (+4 μg m−3). The increase in air pollution exposure during quarantine deepened concerns about the issue of HH air pollution and the clean HH energy transition actions required to eliminate traditional solid fuels.

2.
Nat Hum Behav ; 5(2): 239-246, 2021 02.
Article in English | MEDLINE | ID: covidwho-1007623

ABSTRACT

The COVID-19 quarantine in China is thought to have reduced ambient air pollution. The overall exposure of the population also depends, however, on indoor air quality and human mobility and activities. Here, by integrating real-time mobility data and a questionnaire survey on time-activity patterns during the pandemic, we show that despite a decrease in ambient PM2.5 during the quarantine, the total population-weighted exposure to PM2.5 considering both indoor and outdoor environments increased by 5.7 µg m-3 (95% confidence interval, 1.2-11.0 µg m-3). The increase in population-weighted exposure was mainly driven by a nationwide urban-to-rural population migration before the Spring Festival coupled with the freezing of the migration backward due to the quarantine, which increased household energy consumption and the fraction of people exposed to rural household air pollution indoors. Our analysis reveals an increased inequality of air pollution exposure during the quarantine and highlights the importance of household air pollution for population health in China.


Subject(s)
Air Pollution, Indoor/statistics & numerical data , Air Pollution/statistics & numerical data , COVID-19 , Environmental Exposure/statistics & numerical data , Quarantine , Travel/trends , China , Humans , Particulate Matter , SARS-CoV-2 , Time Factors
3.
Environ Sci Technol ; 55(1): 7-8, 2021 01 05.
Article in English | MEDLINE | ID: covidwho-983888
4.
Innovation (N Y) ; 2(1): 100071, 2021 Feb 28.
Article in English | MEDLINE | ID: covidwho-978457

ABSTRACT

The COVID-19 outbreak has already become a global pandemic and containing this rapid worldwide transmission is of great challenge. The impacts of temperature and humidity on the COVID-19 transmission rate are still under discussion. Here, we elucidated these relationships by utilizing two unique scenarios, repeated measurement and natural experiment, using the COVID-19 cases reported from January 23 - February 21, 2020, in China. The modeling results revealed that higher temperature was most strongly associated with decreased COVID-19 transmission at a lag time of 8 days. Relative humidity (RH) appeared to have only a slight effect. These findings were verified by assessing SARS-CoV-2 infectivity under the relevant conditions of temperature (4°C-37°C) and RH (> 40%). We concluded that temperature increase made an important, but not determined, contribution to restrain the COVID-19 outbreak in China. It suggests that the emphasis of other effective controlling polices should be strictly implemented to restrain COVID-19 transmission in cold seasons.

5.
Environ. Sci. Techno. Lett. ; 6(7): 402-408, 20200609.
Article in English | WHO COVID, ELSEVIER | ID: covidwho-628338

ABSTRACT

The COVID-19 outbreak in China led to dramatic changes in human activities resulting from the sudden infection prevention and control measures. Here, we use ground-level observations and model simulations to examine the nationwide spatial-temporal variations of six air pollutants before and after the initiation of First-Level Public Health Emergency Response. The level of ambient NO2 declined significantly, and in most cities, the decline was dominated by reduced emissions. Meanwhile, the level of O3 increased significantly during this period, and the nonmeteorological factors explained the increase. For the other air pollutants (PM2.5, SO2, and CO), the observed declines on the national scale were obviously affected by the meteorological conditions. In Wuhan, significant declines were found for air pollutants except O3 and emissions dominated the changes, while in Beijing during the same period, only the level of NO2 significantly declined. This study clearly shows that the meteorological changes contributed substantially to the observed changes in most air pollutants, and this must be considered in evaluating the impacts of pollutant source changes on air quality during the specific event and in assessing source-oriented risks.

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