scholarly journals Ground-Based MAX-DOAS Observations of Tropospheric NO2 and HCHO During COVID-19 Lockdown and Spring Festival Over Shanghai, China

2021 ◽  
Vol 13 (3) ◽  
pp. 488
Author(s):  
Aimon Tanvir ◽  
Zeeshan Javed ◽  
Zhu Jian ◽  
Sanbao Zhang ◽  
Muhammad Bilal ◽  
...  

Reduced mobility and less anthropogenic activity under special case circumstances over various parts of the world have pronounced effects on air quality. The objective of this study is to investigate the impact of reduced anthropogenic activity on air quality in the mega city of Shanghai, China. Observations from the highly sophisticated multi-axis differential optical absorption spectroscope (MAX-DOAS) instrument were used for nitrogen dioxide (NO2) and formaldehyde (HCHO) column densities. In situ measurements for NO2, ozone (O3), particulate matter (PM2.5) and the air quality index (AQI) were also used. The concentration of trace gases in the atmosphere reduces significantly during annual Spring Festival holidays, whereby mobility is reduced and anthropogenic activities come to a halt. The COVID-19 lockdown during 2020 resulted in a considerable drop in vertical column densities (VCDs) of HCHO and NO2 during lockdown Level-1, which refers to strict lockdown, i.e., strict measures taken to reduce mobility (43% for NO2; 24% for HCHO), and lockdown Level-2, which refers to relaxed lockdown, i.e., when the mobility restrictions were relaxed somehow (20% for NO2; 22% for HCHO), compared with pre-lockdown days, as measured by the MAX-DOAS instrument. However, for 2019, a reduction in VCDs was found only during Level-1 (24% for NO2; 6.62% for HCHO), when the Spring Festival happened. The weekly cycle for NO2 and HCHO depicts no significant effect of weekends on the lockdown. After the start of the Spring Festival, the VCDs of NO2 and HCHO showed a decline for 2019 as well as 2020. Backward trajectories calculated using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model indicated more air masses coming from the sea after the Spring Festival for 2019 and 2020, implying that a low pollutant load was carried by them. No impact of anthropogenic activity was found on O3 concentration. The results indicate that the ratio of HCHO to NO2 (RFN) fell in the volatile organic compound (VOC)-limited regime.

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 735
Author(s):  
Zeeshan Javed ◽  
Aimon Tanvir ◽  
Yuhang Wang ◽  
Ahmed Waqas ◽  
Mingjie Xie ◽  
...  

The emergence of the novel corona virus and the resulting lockdowns over various parts of the world have substantially impacted air quality due to reduced anthropogenic activity. The objective of this study is to investigate the impact of COVID-19 lockdown and Spring Festival on air quality of four major cities of Yangtze River Delta (YRD) region, including Shanghai, Nanjing, Hefei, and Hangzhou. In situ measurements were taken for nitrogen dioxide (NO2), particulate matter (PM2.5) and ozone (O3). In situ measurements from 1 January to 25 April were taken two years prior to COVID-19 (2018–19), during COVID-19 lockdown (2020), and one year after the COVID-19 (2021). The results indicated that the concentration of NO2 and PM2.5 dropped considerably during the lockdown days compared to normal days while the O3 concentration showed an upsurge. The NO2 showed reduction of about 54% on average during lockdown level 1 in 2020 whereas, PM 2.5 showed reduction of about 36% through the YRD. A substantial drop was observed in concentration of NO2 during the Spring Festival holidays throughout the YRD from 2019 to 2021.


2020 ◽  
Vol 12 (23) ◽  
pp. 3939
Author(s):  
Zeeshan Javed ◽  
Yuhang Wang ◽  
Mingjie Xie ◽  
Aimon Tanvir ◽  
Abdul Rehman ◽  
...  

The spread of the COVID-19 pandemic and consequent lockdowns all over the world have had various impacts on atmospheric quality. This study aimed to investigate the impact of the lockdown on the air quality of Nanjing, China. The off-axis measurements from state-of-the-art remote-sensing Multi-Axis Differential Optical Absorption Spectroscope (MAX-DOAS) were used to observe the trace gases, i.e., Formaldehyde (HCHO), Nitrogen Dioxide (NO2), and Sulfur Dioxide (SO2), along with the in-situ time series of NO2, SO2 and Ozone (O3). The total dataset covers the span of five months, from 1 December 2019, to 10 May 2020, which comprises of four phases, i.e., the pre lockdown phase (1 December 2019, to 23 January 2020), Phase-1 lockdown (24 January 2020, to 26 February 2020), Phase-2 lockdown (27 February 2020, to 31 March 2020), and post lockdown (1 April 2020, to 10 May 2020). The observed results clearly showed that the concentrations of selected pollutants were lower along with improved air quality during the lockdown periods (Phase-1 and Phase-2) with only the exception of O3, which showed an increasing trend during lockdown. The study concluded that limited anthropogenic activities during the spring festival and lockdown phases improved air quality with a significant reduction of selected trace gases, i.e., NO2 59%, HCHO 38%, and SO2 33%. We also compared our results with 2019 data for available gases. Our results imply that the air pollutants concentration reduction in 2019 during Phase-2 was insignificant, which was due to the business as usual conditions after the Spring Festival (Phase-1) in 2019. In contrast, a significant contamination reduction was observed during Phase-2 in 2020 with the enforcement of a Level-II response in lockdown conditions i.e., the easing of the lockdown situation in some sectors during a specific interval of time. The observed ratio of HCHO to NO2 showed that tropospheric ozone production involved Volatile Organic Compounds (VOC) limited scenarios.


2012 ◽  
Vol 12 (23) ◽  
pp. 11631-11645 ◽  
Author(s):  
K. Huang ◽  
G. Zhuang ◽  
Y. Lin ◽  
Q. Wang ◽  
J. S. Fu ◽  
...  

Abstract. The Chinese Spring Festival is one of the most important traditional festivals in China. The peak transport in the Spring Festival season (spring travel rush) provides a unique opportunity for investigating the impact of human activity on air quality in the Chinese megacities. Emission sources are varied and fluctuate greatly before, during and after the Festival. Increased vehicular emissions during the "spring travel rush" before the 2009 Festival resulted in high level pollutants of NOx (270 μg m−3), CO (2572 μg m−3), black carbon (BC) (8.5 μg m−3) and extremely low single scattering albedo of 0.76 in Shanghai, indicating strong, fresh combustion. Organics contributed most to PM2.5, followed by NO3−, NH4+, and SO42−. During the Chinese Lunar New Year's Eve and Day, widespread usage of fireworks caused heavy pollution of extremely high aerosol concentration, scattering coefficient, SO2, and NOx. Due to the "spring travel rush" after the festival, anthropogenic emissions gradually climbed and mirrored corresponding increases in the aerosol components and gaseous pollutants. Secondary inorganic aerosol (SO42−, NO3−, and NH4+) accounted for a dominant fraction of 74% in PM2.5 due to an increase in human activity. There was a greater demand for energy as vast numbers of people using public transportation or driving their own vehicles returned home after the Festival. Factories and constructions sites were operating again. The potential source contribution function (PSCF) analysis illustrated the possible source areas for air pollutants of Shanghai. The effects of regional and long-range transport were both revealed. Five major sources, i.e. natural sources, vehicular emissions, burning of fireworks, industrial and metallurgical emissions, and coal burning were identified using the principle component analysis. The average visibility during the whole study period was less than 6 km. It had been estimated that 50% of the total light extinction was due to the high water vapor in the atmosphere. This study demonstrates that organic aerosol was the largest contributor to aerosol extinction at 47%, followed by sulfate ammonium, nitrate ammonium, and EC at 22%, 14%, and 12%, respectively. Our results indicated the dominant role of traffic-related aerosol species (i.e. organic aerosol, nitrate and EC) on the formation of air pollution, and suggested the importance of controlling vehicle numbers and emissions in mega-cities of China as its population and economy continue to grow.


2020 ◽  
Vol 6 (3) ◽  
pp. 438-441
Author(s):  
Ibrahim Muntasir ◽  
Curci Gabriele ◽  
Habbani Farouk

Satellite remote detecting instruments have been to a great extent used to evaluate air pollutants on the ground and their impacts on human wellbeing. These instruments play an essential job by assessing emanations and air quality models yield. The study concentrated on the analysis of monthly data for the period January 2003 -December 2016 using remote sensing technology and via satellite data products for NASA's Earth navigation satellite. The tools used are Medium Resolution Imaging Spectrophotometer (MODIS), Multi-angle Imaging Spectrophotometer (MISR), the Ozone Monitoring Instrument (OMI), and the Retrospective Analysis of Modern Times for Research and Applications, Version 2 (MERRA-2). Sudan is influenced by airborne particles because of its diverse climate systems, which differ from the desert in the north to poor savanna in the center and to rich savanna in the south. The impact of air pollution is obvious during these years in Sudan. Likewise, OMI trace gas vertical column observations of nitrogen dioxide (NO2) watched higher convergences of tropospheric column NO2 in 2016 than in 2005 over Khartoum that recommends NOx emissions have increased in the city over this time period. The most elevated grouping of dust, a particulate matter (PM2.5), observed in March 2012 over Khartoum state. The highest concentration of sulfur dioxide (SO2) saw by MERRA-2 over Kuwait and South Sudan during December 2015. Noteworthy centralization concentration of black carbon observed over Iraq, Egypt, Central Africa, and South Sudan in December 2015. The most contamination from carbon monoxide watched by MERRA-2 over Iraq and north of Uganda during December 2014.


Author(s):  
Dagnachew Lakew ◽  
Belayneh Ayichew

Aim: The objective of this study was to survey the species composition, relative abundance and to determine major threats of medium and large-sized mammals in Amoro Forest. Method: Linetransects surveying and indirect surveys method (including fresh tracks, scats, hair, spines and burrows) were used to survey mammalian diversity. A survey was conducted in the early morning from 6:00 to 10:00 and late afternoon from 16:00 to 19:00. Key interview and direct site observationswere carried out to assess the major threat of mammals in the study area. Results: A total of 12 species of medium and large sized mammals belonging to sex orders and eight families were recorded. Porcupine (Hystrix cristata), Vervet monkey (Chlorocebus aethiops) and Olive baboon (Papio anubis) were among the medium-sized mammals while, Spotted hyena (Crocuta crocuta),Leopard (Panthera pardus) and Common duiker (Sylvicapra grimmia) were among the large sized mammals observed in the study area. Shannon–Wiener Index values were low (H′ = 1.666) whereas, the Simpson’s index (1-D) of diversity showed the highest species diversity (0.761) in the study area. Illegal logging of trees; overgrazing, agricultural activities and human-wildlife conflicts were the foremost threats in the area. Conclusion: Species richness and evenness were varied from habitat to habitat in Amoro forest. Land degradation anddifferent anthropogenicactivities were common threats for the mammals in the study area. Community participation and awareness creation is very important to limit the impact of anthropogenic activities threatening wildlife. Key words: Anthropogenic activity, Conservation, Diversity, Mammalssurvey


Author(s):  
Nene Anyahara ◽  
Ulunma Nwosu ◽  
Chibueze Awuchi ◽  
Ugochi Obinna

Atmospheric air consist of mixtures of gases composed mainly of nitrogen and oxygen with small proportion of carbon, noble gases and water vapor essential for the sustenance of life on earth. Anthropogenic activities in diverse ways may threaten the quality of atmospheric air and impairs its quality on life. The introduction of any chemical, physical, or biological agent into the atmosphere, in quantities large enough to produce harmful effect to man and its surrounding environment calls for concern. Therefore, an assessment is needed on air quality and on this basis; air quality test was carried out at the mining site at Agalagu Alike in Ikwo Local Government Area of Ebonyi State, and the results collated indicated lesser air pollution across the mine site, except NO2 and SO2. Although the level of NO2 concentration in the study location can be attributed to the activities of mining going on in that area. It was also observed from the results collated that the particulate matter at the study location and immediate environment was very low, which could result from the season of the year (wet season) which the analysis was carried out. Other pollutants like NH3, H2S VOC, and CO were not detected within the coordinates studied in the location. The level of O2 within the location was found to be the same across all the sampling points, with a value of 20.9.


2015 ◽  
Vol 15 (4) ◽  
pp. 2167-2184 ◽  
Author(s):  
S. F. Kong ◽  
L. Li ◽  
X. X. Li ◽  
Y. Yin ◽  
K. Chen ◽  
...  

Abstract. To understand the impact of firework-burning (FW) particles on air quality and human health during the winter haze period, 39 elements, 10 water-soluble ions and 8 fractions of carbonaceous species in atmospheric PM2.5 in Nanjing were investigated during the 2014 Chinese Spring Festival (SF). Serious regional haze pollution persisted throughout the entire sampling period, with PM2.5 averaging at 113 ± 69 μg m−3 and visibility at 4.8 ± 3.2 km. The holiday effect led to almost all the chemical species decreasing during the SF, except for Al, K, Ba and Sr which were related to FW. The source contributions of coal combustion, vehicle emission and road dust decreased dramatically, whereas FW contributed to about half of the PM2.5 during the SF period. The intensive emission of FW particles on New Year's Eve accounted for 60.1% of the PM2.5. Fireworks also obviously modified the chemical compositions of PM2.5, with 39.3% contributed by increased organic matter, followed by steadily increased loadings of secondary inorganic ions. The aging processes of the FW particles lasted for about 4 days reflected by the variations of Ba, Sr, NH4+, NO3−, SO42− and K+, characterized by heterogeneous reactions of SO2 and NOx on crustal materials directly from FW, the replacement of Cl− by NO3− and SO42−, coating of NO3− and SO42− on soot, formation of secondary organic aerosols and metal-catalyzed formation of NO3− and SO42− at higher relative humidity. During aging, the main contributors to the extinction coefficient shifted from elemental carbon and organic matter to ammonium sulfate. The particles raised higher cancer risk of 1.62 × 10−6 by heavy metals (especially for Cd and As). This study provided detailed composition data and first comprehensive analysis of the aging processes of FW particles during the serious haze pollution period and their potential impact on human health.


2021 ◽  
Vol 244 ◽  
pp. 117958
Author(s):  
Nini Pang ◽  
Jian Gao ◽  
Pusheng Zhao ◽  
Yali Wang ◽  
Zhongjun Xu ◽  
...  

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Bakhrom Rajabov ◽  
Lan Liu ◽  
Jamshid Rajabov

From December 2, 2013, to October 31, 2019 (total 2160 days), Beijing official air quality data was used as the research object. The article analyzes the end of days 4 and 9 and the end of the nonrestricted 4 and 9 days, working and nonworking days, restricted and nonrestricted working days, long holidays (Spring Festival and National Day), and nonlong holidays (short holidays other than the Spring Festival and National Day and working days) of AQI, PM2.5, PM10, SO2, CO, NO2, and O3. According to the statistical analysis of the data, the air quality of the 4 and 9 limit is worse than that of the non-4 and 9 limit. Motor vehicles restricted in traffic had an objective effect on air AQI, PM2.5, PM10, CO, and NO2, whereas there was almost no difference in O3. Some peak values of AQI, PM2.5, PM10, SO2, CO, and NO2 on nonrestricted working days were significantly higher than those on restricted working days. At the same time, there was a peak time of the impact of motor vehicles on AQI, PM2.5, PM10, SO2, CO, and NO2 in Beijing. This time should be between 3 and 5 days, or 72 and 120 hours.


2014 ◽  
Vol 14 (21) ◽  
pp. 28609-28655 ◽  
Author(s):  
S. Kong ◽  
L. Li ◽  
X. Li ◽  
Y. Yin ◽  
K. Chen ◽  
...  

Abstract. To understand the impact of fireworks burning (FW) particles on air quality and human health during winter haze period, thirty-nine elements, ten water-soluble ions and eight fractions of carbonaceous species in atmospheric PM2.5 at Nanjing were investigated during 2014 Chinese Spring Festival (SF). Serious regional haze pollution persisted throughout the entire sampling period, PM2.5 averaging at 113 ± 69 μg m−3 and visibility at 4.8 ± 3.2 km. The holiday effect led to almost all the chemical species decreasing during the SF, except for Al, K, Ba and Sr which were related to FW. The source contributions of coal combustion, vehicle emission and road dust descreased dramatically, whereas FW contributed to about half of the PM2.5 during SF period. The intensive emission of FW particles at New Year's Eve accounted for 60.1% of the PM2.5. They also significnatly modified the chemical compositions of PM2.5, with 39.3% contributed by increased organic matter, followed by steadly increased loadings of secondary inorganic ions. The aging processes of the FW particles lasted for at least six days reflected by the variation of SO42−, characterized by heterogeneous reactions of SO2 and NOx on crustal materials directly from FW, the replacement of Cl− by NO3− and SO42− coating of NO3− and SO42− on soot, formation of secondary organic aerosols and metal-catalyzed formation of NO3− and SO42− at higher relative humidity. During aging, the main contributors to the extinction coefficient shifted from elemental carbon and organic matter to sulfate ammonium. The particles raised higher cancer risks by heavy metals (especially for Cd and As) as 1.62 ×10−6. This study provided detailed composition data and first comprehensive analysis of the aging processes of FW particles at serious haze pollution period and their potential impact on human health.


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