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1.
Int J Environ Res Public Health ; 17(17)2020 08 27.
Article in English | MEDLINE | ID: covidwho-836247

ABSTRACT

Seoul, the most populous city in South Korea, has been practicing social distancing to slow down the spread of coronavirus disease 2019 (COVID-19). Fine particulate matter (PM2.5) and other air pollutants measured in Seoul over the two 30 day periods before and after the start of social distancing are analyzed to assess the change in air quality during the period of social distancing. The 30 day mean PM2.5 concentration decreased by 10.4% in 2020, which is contrasted with an average increase of 23.7% over the corresponding periods in the previous 5 years. The PM2.5 concentration decrease was city-wide and more prominent during daytime than at nighttime. The concentrations of carbon monoxide (CO) and nitrogen dioxide (NO2) decreased by 16.9% and 16.4%, respectively. These results show that social distancing, a weaker forcing toward reduced human activity than a strict lockdown, can help lower pollutant emissions. At the same time, synoptic conditions and the decrease in aerosol optical depth over the regions to the west of Seoul support that the change in Seoul's air quality during the COVID-19 social distancing can be interpreted as having been affected by reductions in the long-range transport of air pollutants as well as local emission reductions.


Subject(s)
Air Pollution/analysis , Coronavirus Infections/epidemiology , Environmental Monitoring , Pneumonia, Viral/epidemiology , Air Pollutants/analysis , Betacoronavirus , Humans , Pandemics , Particulate Matter/analysis , Seoul
3.
J Acoust Soc Am ; 148(3): 1748, 2020 09.
Article in English | MEDLINE | ID: covidwho-811488

ABSTRACT

The lockdown that Madrid has suffered during the months of March to June 2020 to try to control and minimize the spread of COVID-19 has significantly altered the acoustic environment of the city. The absence of vehicles and people on the streets has led to a noise reduction captured by the monitoring network of the City of Madrid. In this article, an analysis has been carried out to describe the reduction in noise pollution that has occurred and to analyze the changes in the temporal patterns of noise, which are strongly correlated with the adaptation of the population's activity and behavior to the new circumstances. The reduction in the sound level ranged from 4 to 6 dBA for the indicators Ld, Le, and Ln, and this is connected to a significant variation in the daily time patterns, especially during weekends, when the activity started earlier in the morning and lasted longer at midday, decreasing significantly in the afternoon.


Subject(s)
Coronavirus Infections , Noise , Pandemics , Pneumonia, Viral , Betacoronavirus , Cities , Environmental Monitoring , Humans , Spain
4.
Philos Trans A Math Phys Eng Sci ; 378(2183): 20200188, 2020 Oct 30.
Article in English | MEDLINE | ID: covidwho-801118

ABSTRACT

We suggest that the unprecedented and unintended decrease of emissions of air pollutants during the COVID-19 lock-down in 2020 could lead to declining seasonal ozone concentrations and positive impacts on crop yields. An initial assessment of the potential effects of COVID-19 emission reductions was made using a set of six scenarios that variously assumed annual European and global emission reductions of 30% and 50% for the energy, industry, road transport and international shipping sectors, and 80% for the aviation sector. The greatest ozone reductions during the growing season reached up to 12 ppb over crop growing regions in Asia and up to 6 ppb in North America and Europe for the 50% global reduction scenario. In Europe, ozone responses are more sensitive to emission declines in other continents, international shipping and aviation than to emissions changes within Europe. We demonstrate that for wheat the overall magnitude of ozone precursor emission changes could lead to yield improvements between 2% and 8%. The expected magnitude of ozone precursor emission reductions during the Northern Hemisphere growing season in 2020 presents an opportunity to test and improve crop models and experimentally based exposure response relationships of ozone impacts on crops, under real-world conditions. This article is part of a discussion meeting issue 'Air quality, past present and future'.


Subject(s)
Air Pollution/analysis , Betacoronavirus , Coronavirus Infections/epidemiology , Crops, Agricultural/drug effects , Crops, Agricultural/growth & development , Ozone/analysis , Pandemics , Pneumonia, Viral/epidemiology , Air Pollutants/analysis , Air Pollutants/toxicity , Air Pollution/prevention & control , Air Pollution/statistics & numerical data , Environmental Monitoring , Europe , Humans , Models, Biological , Nitrogen Dioxide/analysis , Nitrogen Dioxide/toxicity , Ozone/toxicity , Risk Assessment , Seasons
5.
Sci Total Environ ; 746: 141129, 2020 Dec 01.
Article in English | MEDLINE | ID: covidwho-676570

ABSTRACT

The current changes in vehicle movement due to 'lockdown' conditions (imposed in cities worldwide in response to the COVID-19 epidemic) provide opportunities to quantify the local impact of 'controlled interventions' on air quality and establish baseline pollution concentrations in cities. Here, we present a case study from Auckland, New Zealand, an isolated Southern Hemisphere city, which is largely unaffected by long-range pollution transport or industrial sources of air pollution. In this city, traffic flows reduced by 60-80% as a result of a government-led initiative to contain the virus by limiting all transport to only essential services. In this paper, ambient pollutant concentrations of NO2, O3, BC, PM2.5, and PM10 are compared between the lockdown period and comparable periods in the historical air pollution record, while taking into account changes in the local meteorology. We show that this 'natural experiment' in source emission reductions had significant but non-linear impacts on air quality. While emission inventories and receptor modelling approaches confirm the dominance of traffic sources for NOx (86%), and BC (72%) across the city, observations suggest a consequent reduction in NO2 of only 34-57% and a reduction in BC of 55-75%. The observed reductions in PM2.5 (still likely to be dominated by traffic emissions), and PM10 (dominated by sea salt, traffic emissions to a lesser extent, and affected by seasonality) were found to be significantly less (8-17% for PM2.5 and 7-20% for PM10). The impact of this unplanned controlled intervention shows the importance of establishing accurate, local-scale emission inventories, and the potential of the local atmospheric chemistry and meteorology in limiting their accuracy.


Subject(s)
Air Pollutants/analysis , Air Pollution/analysis , Air Pollution/prevention & control , Coronavirus Infections , Pandemics , Pneumonia, Viral , Severe Acute Respiratory Syndrome , Betacoronavirus , Cities , Environmental Monitoring , Humans , New Zealand/epidemiology , Particulate Matter/analysis
6.
Sci Total Environ ; 743: 140758, 2020 Nov 15.
Article in English | MEDLINE | ID: covidwho-652608

ABSTRACT

The COVID-19 epidemic broke out in Wuhan, Hubei in December 2019 and in January 2020 and was later transmitted to the entire country. Quarantine measures during Chinese New Year effectively alleviated the spread of the epidemic, but they simultaneously resulted in a decline in anthropogenic emissions from industry, transportation, and import and export of goods. Herein, we present the major chemical composition of non-refractory PM2.5 (NR-PM2.5) and the concentrations of gaseous pollutants in an urban site in Shanghai before and during the quarantine period of the COVID-19 epidemic, which was Jan. 8-23 and Jan. 24-Feb. 8, respectively. The observed results show that the reduction in PM2.5 can be mainly attributed to decreasing concentrations of nitrate and primary aerosols. Nitrate accounted for 37% of NR-PM2.5 before the quarantine period when there was no emission reduction. During the quarantine period, the nitrate concentration decreased by approximately 60%, which is attributed to a reduction in the NOx concentration. Ammonium, as the main balancing cation, showed an approximately 45% simultaneous decrease in concentration. The concentrations of chloride and hydrocarbon-like organic aerosols from primary emissions also declined due to limited human activities. By contrast, sulphate and oxygenated organic aerosols showed a slight decrease in concentration, with their contributions increasing to 27% and 18%, respectively, during the quarantine period, which resulted in two pollution episodes with PM2.5 exceeding 100 µg/m3. This study provides a better understanding of the impact of quarantine measures on variations of the PM2.5 concentration and chemical compositions. Atmospheric oxidation capacities based on the oxidant (Ox = O3 + NO2) and oxidation ratios have been discussed for elucidating the source and formation of haze in an environment with lower anthropogenic emissions. With increasing contribution of secondary aerosols, lower NOx and nitrate concentrations did not completely avoid haze in Shanghai during the epidemic.


Subject(s)
Air Pollutants/analysis , Coronavirus Infections , Pandemics , Particulate Matter/analysis , Pneumonia, Viral , Aerosols/analysis , Betacoronavirus , China , Environmental Monitoring , Humans , Quarantine , Seasons
7.
Environ Res ; 189: 109949, 2020 10.
Article in English | MEDLINE | ID: covidwho-654782

ABSTRACT

Sustainable development calls for a blue sky with quality air. Encouragingly, the current mass reduction-oriented pollution control is making substantial achievements, as the data from Chinese Environmental Monitoring Stations show a significant drop in the annual average concentrations of particulate matters (i.e., PM10 and PM2.5) and SO2. But many challenges and knowledge gaps are still confronted nowadays. On one hand, long-term health impacts of fine air particles have to be closely probed through both epidemiological and laboratory studies, and the toxic effects owing to the interactions between particles and associated chemical pollutants should be differentially teased out. On the other hand, due to sole mass control, there are significant changes of overall pollutant fingerprint, such as the increase of ground-level ozone concentration, which should be taken into account for altered health effects relative to the past. Moreover, the interplays with air pollutants and air-borne pathogens should be scrutinized in more details. In other words, it is worth investigating likely spread of pathogens (even for SARS-CoV-2) with aid of aerosols. Here, we recapitulate the current knowledge gaps between air pollution controls and health impacts including pathogen epidemic, and we also propose future research directions to support policy making in balance mass control and health impacts.


Subject(s)
Air Pollution/adverse effects , Air Pollution/prevention & control , Environmental Monitoring , Air Pollutants , Betacoronavirus , Coronavirus Infections/prevention & control , Humans , Pandemics/prevention & control , Particulate Matter , Pneumonia, Viral/prevention & control
8.
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
10.
Int J Environ Res Public Health ; 17(17)2020 08 28.
Article in English | MEDLINE | ID: covidwho-740492

ABSTRACT

Due to the suspension of traffic mobility and industrial activities during the COVID-19, particulate matter (PM) pollution has decreased in China. However, rarely have research studies discussed the spatiotemporal pattern of this change and related influencing factors at city-scale across the nation. In this research, the clustering patterns of the decline rates of PM2.5 and PM10 during the period from 20 January to 8 April in 2020, compared with the same period of 2019, were investigated using spatial autocorrelation analysis. Four meteorological factors and two socioeconomic factors, i.e., the decline of intra-city mobility intensity (dIMI) representing the effect of traffic mobility and the decline rates of the secondary industrial output values (drSIOV), were adopted in the regression analysis. Then, multi-scale geographically weighted regression (MGWR), a model allowing the particular processing scale for each independent variable, was applied for investigating the relationship between PM pollution reductions and influencing factors. For comparison, ordinary least square (OLS) regression and the classic geographically weighted regression (GWR) were also performed. The research found that there were 16% and 20% reduction of PM2.5 and PM10 concentration across China and significant PM pollution mitigation in central, east, and south regions of China. As for the regression analysis results, MGWR outperformed the other two models, with R2 of 0.711 and 0.732 for PM2.5 and PM10, respectively. The results of MGWR revealed that the two socioeconomic factors had more significant impacts than meteorological factors. It showed that the reduction of traffic mobility caused more relative declines of PM2.5 in east China (e.g., cities in Jiangsu), while it caused more relative declines of PM10 in central China (e.g., cities in Henan). The reduction of industrial operation had a strong relationship with the PM10 drop in northeast China. The results are crucial for understanding how the decline pattern of PM pollution varied spatially during the COVID-19 outbreak, and it also provides a good reference for air pollution control in the future.


Subject(s)
Air Pollutants/analysis , Coronavirus Infections/epidemiology , Environmental Monitoring , Particulate Matter/analysis , Pneumonia, Viral/epidemiology , Air Pollution/analysis , Betacoronavirus , China , Cities , Humans , Pandemics
11.
Int J Environ Res Public Health ; 17(17)2020 08 27.
Article in English | MEDLINE | ID: covidwho-738138

ABSTRACT

Seoul, the most populous city in South Korea, has been practicing social distancing to slow down the spread of coronavirus disease 2019 (COVID-19). Fine particulate matter (PM2.5) and other air pollutants measured in Seoul over the two 30 day periods before and after the start of social distancing are analyzed to assess the change in air quality during the period of social distancing. The 30 day mean PM2.5 concentration decreased by 10.4% in 2020, which is contrasted with an average increase of 23.7% over the corresponding periods in the previous 5 years. The PM2.5 concentration decrease was city-wide and more prominent during daytime than at nighttime. The concentrations of carbon monoxide (CO) and nitrogen dioxide (NO2) decreased by 16.9% and 16.4%, respectively. These results show that social distancing, a weaker forcing toward reduced human activity than a strict lockdown, can help lower pollutant emissions. At the same time, synoptic conditions and the decrease in aerosol optical depth over the regions to the west of Seoul support that the change in Seoul's air quality during the COVID-19 social distancing can be interpreted as having been affected by reductions in the long-range transport of air pollutants as well as local emission reductions.


Subject(s)
Air Pollution/analysis , Coronavirus Infections/epidemiology , Environmental Monitoring , Pneumonia, Viral/epidemiology , Air Pollutants/analysis , Betacoronavirus , Humans , Pandemics , Particulate Matter/analysis , Seoul
15.
Environ Pollut ; 266(Pt 3): 115368, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-712305

ABSTRACT

Lockdown measures to contain COVID-19 pandemic has resulted in a considerable change in air pollution worldwide. We estimate the temporal and diurnal changes of the six criteria air pollutants, including particulate matter (PM2.5 and PM10) and gaseous pollutants (NO2, O3, CO, and SO2) during lockdown (25th March - 3rd May 2020) across regions of India using the observations from 134 real-time monitoring sites of Central Pollution Control Board (CPCB). Significant reduction in PM2.5, PM10, NO2, and CO has been found in all the regions during the lockdown. SO2 showed mixed behavior, with a slight increase at some sites but a comparatively significant decrease at other locations. O3 also showed a mixed variation with a mild increase in IGP and a decrease in the South. The absolute decrease in PM2.5, PM10, and NO2 was observed during peak morning traffic hours (08-10 Hrs) and late evening (20-24 Hrs), but the percentage reduction is almost constant throughout the day. A significant decrease in day-time O3 has been found over Indo Gangetic plain (IGP) and central India, whereas night-time O3 has increased over IGP due to less O3 loss. The most significant reduction (∼40-60%) was found in PM2.5 and PM10. The highest decrease in PM was found for the north-west and IGP followed by South and central regions. A considerable reduction (∼30-70%) in NO2 was found except for a few sites in the central region. A similar pattern was observed for CO having a ∼20-40% reduction. The reduction observed for PM2.5, PM10, NO2, and enhancement in O3 was proportional to the population density. Delhi's air quality has improved with a significant reduction in primary pollutants, however, an increase in O3 was observed. The changes reported during the lockdown are combined effect of changes in the emissions, meteorology, and atmospheric chemistry that requires detailed investigations.


Subject(s)
Air Pollutants/analysis , Air Pollution/analysis , Coronavirus Infections , Pandemics , Pneumonia, Viral , Betacoronavirus , Environmental Monitoring , Humans , India , Particulate Matter/analysis
16.
Sci Rep ; 10(1): 13442, 2020 08 10.
Article in English | MEDLINE | ID: covidwho-709952

ABSTRACT

Delhi, a tropical Indian megacity, experiences one of the most severe air pollution in the world, linked with diverse anthropogenic and biomass burning emissions. First phase of COVID-19 lockdown in India, implemented during 25 March to 14 April 2020 resulted in a dramatic near-zeroing of various activities (e.g. traffic, industries, constructions), except the "essential services". Here, we analysed variations in the fine particulate matter (PM2.5) over the Delhi-National Capital Region. Measurements revealed large reductions (by 40-70%) in PM2.5 during the first week of lockdown (25-31 March 2020) as compared to the pre-lockdown conditions. However, O3 pollution remained high during the lockdown due to non-linear chemistry and dynamics under low aerosol loading. Notably, events of enhanced PM2.5 levels (300-400 µg m-3) were observed during night and early morning hours in the first week of April after air temperatures fell close to the dew-point (~ 15-17 °C). A haze formation mechanism is suggested through uplifting of fine particles, which is reinforced by condensation of moisture following the sunrise. The study highlights a highly complex interplay between the baseline pollution and meteorology leading to counter intuitive enhancements in pollution, besides an overall improvement in air quality during the COVID-19 lockdown in this part of the world.


Subject(s)
Air Pollutants/analysis , Betacoronavirus , Coronavirus Infections/epidemiology , Coronavirus Infections/prevention & control , Pandemics/prevention & control , Particulate Matter/analysis , Pneumonia, Viral/epidemiology , Pneumonia, Viral/prevention & control , Quarantine/methods , Weather , Aerosols/analysis , Air Pollution/analysis , Cities/epidemiology , Coronavirus Infections/virology , Environmental Monitoring/methods , Humans , India/epidemiology , Ozone/analysis , Pneumonia, Viral/virology , Temperature
18.
Sci Total Environ ; 746: 141320, 2020 Dec 01.
Article in English | MEDLINE | ID: covidwho-703255

ABSTRACT

The COVID-19 pandemic has triggered an industrial and financial slowdown due to unprecedented regulations imposed with the purpose to contain the spread of the virus. Consequently, the positive effect on the environment has been witnessed. One of the most prominent evidences has been the drastic air quality improvement, as a direct consequence of lower emissions from reduced industrial activity. While several studies have demonstrated the validity of this hypothesis in mega-cities worldwide, it is still an unsubstantiated fact whether the same holds true for cities with a smaller urban extent and population. In the present study we investigate the temporal development of atmospheric constituent concentrations as retrieved concurrently from the Sentinel-5P satellite and a ground meteorological station. We focus on the period before and during the COVID-19 pandemic over the city of Hat Yai, Thailand and present the effect of the lockdown on the atmospheric quality over this average populated city (156,000 inhabitants). NO2, PM2.5 and PM10 concentrations decreased by 33.7%, 21.8% and 22.9% respectively in the first 3 weeks of the lockdown compared to the respective pre-lockdown period; O3 also decreased by 12.5% and contrary to similar studies. Monthly averages of NO2, CO and PM2.5 for the month April exhibit in 2020 the lowest values in the last decade. Sentinel-5P retrieved NO2 tropospheric concentrations, both locally over the ground station and the spatial average over the urban extent of the city, are in agreement with the reduction observed from the ground station. Numerous studies have already presented evidence of the bettering of the air quality over large metropolitan areas during the COVID-19 pandemic. In the current study we demonstrate that this holds true for Hat Yai, Thailand; we propound that the environmental benefits documented in major urban agglomerations during the lockdown may extend to medium-sized urban areas as well.


Subject(s)
Air Pollutants/analysis , Air Pollution/analysis , Coronavirus Infections , Pandemics , Pneumonia, Viral , Betacoronavirus , Cities , Environmental Monitoring , Humans , Particulate Matter/analysis , Thailand/epidemiology
19.
Environ Pollut ; 266(Pt 1): 115080, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-679962

ABSTRACT

The study objective is to contemplate the effectiveness of COVID-19 on the air pollution of Indian territory from January 2020 to April 2020. We have executed data from European Space Agency (ESA) and CPCB online portal for air quality data dissemination. The Sentinel - 5 P satellite images elucidate that the Air quality of Indian territory has been improved significantly during COVID-19. Mumbai and Delhi are one of the most populated cities. These two cities have observed a substantial decrease in Nitrogen Dioxide (40-50%) compared to the same period last year. It suggests that the emergence of COVID-19 has been proved to a necessary evil as being advantageous for mitigating air pollution on Indian territory during the lock-down. The study found a significant decline in Nitrogen Dioxide in reputed states of India, i.e., Delhi and Mumbai. Moreover, a faded track of Nitrogen Dioxide can be seen at the Maritime route in the Indian Ocean. An upsurge in the environmental quality of India will also be beneficial for its neighbor countries, i.e., China, Pakistan, Iran, and Afghanistan.


Subject(s)
Air Pollutants/analysis , Air Pollution/analysis , Coronavirus Infections , Pandemics , Pneumonia, Viral , Betacoronavirus , China , Cities , Environmental Monitoring , Humans , India , Indian Ocean , Iran , Pakistan , Particulate Matter/analysis
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