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1.
Sci Total Environ ; 742: 140931, 2020 Nov 10.
Article in English | MEDLINE | ID: covidwho-641193

ABSTRACT

We investigated changes in traffic-related air pollutant concentrations in an urban area during the COVID-19 pandemic. The study was conducted in a mixed commercial-residential neighborhood in Somerville (MA, USA), where traffic is the dominant source of air pollution. Measurements were made between March 27 and May 14, 2020, coinciding with a dramatic reduction in traffic (71% drop in car and 46% drop in truck traffic) due to business shutdowns and a statewide stay-at-home advisory. Indicators of fresh vehicular emissions (ultrafine particle number concentration [PNC] and black carbon [BC]) were measured with a mobile monitoring platform on an interstate highway and major and minor roadways. Our results show that depending on road class, median PNC and BC contributions from traffic were 60-68% and 22-46% lower, respectively, during the lockdown compared to pre-pandemic conditions, and corresponding reductions in total on-road concentrations were 45-69% and 22-56%, respectively. A higher BC: PNC concentration ratio was observed during the lockdown period likely indicative of the higher fraction of diesel vehicles in the fleet during the lockdown. Overall, the scale of reductions in ultrafine particle and BC concentrations was commensurate with the reductions in traffic. This natural experiment allowed us to quantify the direct impacts of reductions in traffic emissions on neighborhood-scale air quality, which are not captured by the regional regulatory-monitoring network. These results underscore the importance of measurements of appropriate proxies for traffic emissions at relevant spatial scales. Our results are useful for exposure analysis as well as city and regional planners evaluating mitigation strategies for traffic-related air pollution.


Subject(s)
Air Pollutants/analysis , Air Pollution/analysis , Coronavirus Infections , Pandemics , Pneumonia, Viral , Betacoronavirus , Carbon , Cities , Environmental Monitoring , Humans , Particulate Matter/analysis , Vehicle Emissions/analysis
2.
Proc Natl Acad Sci U S A ; 117(32): 18984-18990, 2020 08 11.
Article in English | MEDLINE | ID: covidwho-691222

ABSTRACT

The lockdown response to coronavirus disease 2019 (COVID-19) has caused an unprecedented reduction in global economic and transport activity. We test the hypothesis that this has reduced tropospheric and ground-level air pollution concentrations, using satellite data and a network of >10,000 air quality stations. After accounting for the effects of meteorological variability, we find declines in the population-weighted concentration of ground-level nitrogen dioxide (NO2: 60% with 95% CI 48 to 72%), and fine particulate matter (PM2.5: 31%; 95% CI: 17 to 45%), with marginal increases in ozone (O3: 4%; 95% CI: -2 to 10%) in 34 countries during lockdown dates up until 15 May. Except for ozone, satellite measurements of the troposphere indicate much smaller reductions, highlighting the spatial variability of pollutant anomalies attributable to complex NOx chemistry and long-distance transport of fine particulate matter with a diameter less than 2.5 µm (PM2.5). By leveraging Google and Apple mobility data, we find empirical evidence for a link between global vehicle transportation declines and the reduction of ambient NO2 exposure. While the state of global lockdown is not sustainable, these findings allude to the potential for mitigating public health risk by reducing "business as usual" air pollutant emissions from economic activities. Explore trends here: https://nina.earthengine.app/view/lockdown-pollution.


Subject(s)
Air Pollution/statistics & numerical data , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Quarantine/statistics & numerical data , Air Pollutants/analysis , Atmosphere/chemistry , Coronavirus Infections/prevention & control , Humans , Nitrogen Dioxide/analysis , Ozone/analysis , Pandemics/prevention & control , Particulate Matter/analysis , Pneumonia, Viral/prevention & control , Quarantine/economics , Vehicle Emissions/analysis
3.
Bull Environ Contam Toxicol ; 105(2): 198-204, 2020 Aug.
Article in English | MEDLINE | ID: covidwho-645142

ABSTRACT

The corona virus-2019 (COVID-19) is ravaging the whole world. Scientists have been trying to acquire more knowledge on different aspects of COVID-19. This study attempts to determine the effects of COVID-19, on a large population, which has already been persistently exposed to various atmospheric pollutants in different parts of India. Atmospheric pollutants and COVID-19 data, obtained from online resources, were used in this study. This study has shown strong positive correlation between the concentration of atmospheric nitrogen dioxide (NO2) and both the absolute number of COVID-19 deaths (r = 0.79, p < 0.05) and case fatality rate (r = 0.74, p < 0.05) in India. Statistical analysis of the amount of annual fossil fuels consumption in transportation, and the annual average concentration of the atmospheric PM2.5, PM10, NO2, in the different states of India, suggest that one of the main sources of atmospheric NO2 is from fossil fuels combustion in transportation. It is suggested that homeless, poverty-stricken Indians, hawkers, roadside vendors, and many others who are regularly exposed to vehicular exhaust, may be at a higher risk in the COVID-19 pandemic.


Subject(s)
Air Pollutants/analysis , Coronavirus Infections/epidemiology , Nitrogen Dioxide/analysis , Pneumonia, Viral/epidemiology , Vehicle Emissions/analysis , Air Pollution/analysis , Coronavirus Infections/mortality , Humans , India/epidemiology , Pandemics , Particulate Matter/analysis , Pneumonia, Viral/mortality
4.
Sci Total Environ ; 744: 140840, 2020 Nov 20.
Article in English | MEDLINE | ID: covidwho-643247

ABSTRACT

To control the spread of the novel coronavirus disease 2019 (COVID-19) in China, many anthropogenic activities were reduced and even closed on the national scale. To study the impact of this reduction and closing down, hourly concentrations of PM2.5-related elements were measured at a rural site before (12-25 January 2020), during (26 January-9 February 2020) and after (22 March-2 April 2020) the control period when all people remained socially isolated in their homes and could not return to economic zones for work. Nine major sources were identified by the positive matrix factorization model, including fireworks burning, coal combustion, vehicle emissions, dust, Cr industry, oil combustion, Se industry, Zn smelter, and iron and steel industry. Before the control period, K, Fe, Ca, Zn, Ba and Cu were the main elements, and fireworks burning, Zn smelter and vehicle emissions provided the highest contributions to the total element mass with 55%, 12.1% and 10.3%, respectively. During the control period, K, Fe, Ba, Cu and Zn were the dominating elements, and fireworks burning and vehicle emissions contributed 55% and 27% of the total element mass. After the control period, Fe, K, Ca, Zn and Ba were the main elements, and dust and iron and steel industry were responsible for 56% and 21% of the total element mass. The increased contribution from vehicle emissions during the control period could be attributed to our sampling site being near a town hospital and the fact that the vehicle activities were not restricted. The source apportionment results were also related to air mass backward trajectories. The largest reductions of dust, coal combustion, and the industrial sources (Cr industry, Zn smelter, Se industry, iron and steel industry) were distinctly seen for northwest transport (Ulanqab) and were least significant for northeast transport (Tangshan and Tianjin).


Subject(s)
Air Pollutants/analysis , Coronavirus Infections , Coronavirus , Pandemics , Pneumonia, Viral , Beijing , Betacoronavirus , China , Cities , Dust/analysis , Environmental Monitoring , Humans , Particulate Matter/analysis , Seasons , Vehicle Emissions/analysis
5.
Bull Environ Contam Toxicol ; 105(1): 2-8, 2020 Jul.
Article in English | MEDLINE | ID: covidwho-597452

ABSTRACT

As COVID-19 spread all over the world, most of the countries adopted some kind of restrictions to avoid the collapse of health systems. In Brazil, São Paulo and Rio the Janeiro, the two most populated cities in the country, were the first to determine social distancing. In this study, the impact of the social distancing measures on the concentrations of the three main primary air pollutants (PM10, NO2 and CO) was analyzed. CO levels showed the most significant reductions (up to 100%) since it is related to light-duty vehicular emissions. NO2 also showed reductions (9.1%-41.8%) while PM10 levels were only reduced in the 1st lockdown week. The decrease of pollutants was not directly proportional to the vehicular flux reduction, because it depends on other factors such as the transport of air masses from industrial and rural areas. The differences observed can be explained considering the fleet characteristics in the two cities and the response of the population to the social distancing recommendations.


Subject(s)
Air Pollution/analysis , Atmosphere/chemistry , Communicable Disease Control/statistics & numerical data , Disease Outbreaks/legislation & jurisprudence , Environmental Monitoring , Pandemics/statistics & numerical data , Betacoronavirus , Brazil , Cities , Coronavirus Infections/prevention & control , Disease Outbreaks/prevention & control , Humans , Pandemics/prevention & control , Particulate Matter/analysis , Pneumonia, Viral/prevention & control , Vehicle Emissions/analysis
6.
Sci Total Environ ; 739: 140000, 2020 Oct 15.
Article in English | MEDLINE | ID: covidwho-548125

ABSTRACT

Wuhan was the first city to adopt the lockdown measures to prevent COVID-19 spreading, which improved the air quality accordingly. This study investigated the variations in chemical compositions, source contributions, and regional transport of fine particles (PM2.5) during January 23-February 22 of 2020, compared with the same period in 2019. The average mass concentration of PM2.5 decreased from 72.9 µg m-3 (2019) to 45.9 µg m-3 (2020), by 27.0 µg m-3. It was predominantly contributed by the emission reduction (92.0%), retrieved from a random forest tree approach. The main chemical species of PM2.5 all decreased with the reductions ranging from 0.85 µg m-3 (chloride) to 9.86 µg m-3 (nitrate) (p < 0.01). Positive matrix factorization model indicated that the mass contributions of seven PM2.5 sources all decreased. However, their contribution percentages varied from -11.0% (industrial processes) to 8.70% (secondary inorganic aerosol). Source contributions of PM2.5 transported from potential geographical regions showed reductions with mean values ranging from 0.22 to 4.36 µg m-3. However, increased contributions of firework burning, secondary inorganic aerosol, road dust, and vehicle emissions from transboundary transport were observed. This study highlighted the complex and nonlinear response of chemical compositions and sources of PM2.5 to air pollution control measures, suggesting the importance of regional-joint control.


Subject(s)
Air Pollutants/analysis , Coronavirus Infections , Pandemics , Particulate Matter/analysis , Pneumonia, Viral , Betacoronavirus , Cities , Environmental Monitoring , Humans , Vehicle Emissions/analysis
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