Assessment of atmospheric aerosols over Varanasi: Physical, optical and chemical properties and meteorological implications

Kumar, Pradeep; Pratap, Vineet; Kumar, Akhilesh; Choudhary, Arti; Prasad, Rajendra; Shukla, Anuradha; Singh, R. P.; Singh, Abhay Kumar

doi:10.1016/j.jastp.2020.105424

Cited by 26 publications

(12 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Varanasi (25.26 • N, 82.99 • E, 83 m above mean sea level) is situated in the eastern part of Uttar Pradesh, which is a semi-urban city in the central Gangetic Plain and has various sources of contaminated pollutants and suffers from high particulate loading (Ram and Sarin, 2011;Tiwari and Singh, 2013;Kumar et al, 2015b;Tiwari et al, 2018). The Indo-Gangetic Plain (IGP) runs parallel to the Himalayan range, having a stretch of 2400 km from Jammu and Kashmir in the west to the Assam in the east, and has a significant aerosol hotspot of air contaminants due to its unique geomorphology, weather patterns, and climatic susceptibility (Dey et al, 2004;Ramachandran and Kedia, 2010;Srivastava et al, 2012b;Kumar et al, 2020;Pratap et al, 2020a). During the pre-monsoon season in which hot and dry summer exists, coarse-mode aerosol prevails, and extreme rainfall occurs during monsoon whereas an excess of fine-mode aerosols in extremely cold weather during winter and post-monsoon was reported (Satheesh et al, 2006;Tiwari et al, 2018).…”

Section: Site Description and Meteorological Conditionmentioning

confidence: 99%

Seasonal characteristics of PM1, PM2.5, and PM10 over Varanasi during 2019–2020

Chauhan

Kumar²,

Pratap

et al. 2022

Front. Sustain. Cities

Self Cite

View full text Add to dashboard Cite

Particulate matter (PM) concentrations and aerosol optical depth (AOD) are measured and correlated simultaneously using a high-volume sampler and a MICROTOPS-II Sunphotometer, respectively. The present work deals with the characteristics of particulate matter (PM1, PM2.5, and PM10) over Varanasi, from April 2019 to March 2020. Daily variation, as well as seasonal variation, reveals the dominancy of fine-mode particles over the Varanasi region in the winter season and the dominancy of coarse-mode particles in the summer season, which was further confirmed by calculating the ratio between particulate matter (PM1/PM10 and PM2.5/PM10). This ratio was discovered to be lowest in the summer and highest in the winter. Annual mean concentrations of PM1, PM2.5, and PM10 are found to be 93.91, 111.34, and 180.70 μgm−3, respectively. The seasonal variation shows relatively a higher concentration of PM1, PM2.5, and PM10 in the winter season, which may be due to stable meteorological conditions and increased biomass burning in winter. Diurnal and seasonal variations in AOD were also studied during this period. A large and small value of AOD represents the dominancy of fine particles over coarse particles. At 500 nm, maximum (1.17) and minimum (0.44) AODs were measured in December and August of 2019, respectively. There was a statistically significant correlation between PM particles (PM1, PM2.5, and PM10) and AOD. Elemental analysis shows that fluorine and carbon are the major elements that were observed in selected samples during the post-monsoon and winter season using SEM-EDX analysis.

show abstract

Section: Site Description and Meteorological Conditionmentioning

confidence: 99%

Seasonal characteristics of PM1, PM2.5, and PM10 over Varanasi during 2019–2020

Chauhan

Kumar²,

Pratap

et al. 2022

Front. Sustain. Cities

Self Cite

View full text Add to dashboard Cite

show abstract

“…An aerosol source apportionment study in Varanasi by Kumar et al ( 2020a ), Kumar et al ( 2020b )) showed that during the months of post-monsoon and winter periods from October to February, the particles are mainly from biofuel and vehicular emissions. With the imposition of lockdown, the main emission source was cut down leading to the observed reduction in ambient concentration of particulate matters.…”

Section: Resultsmentioning

confidence: 99%

“…Using the ratio of NO 2 and HCHO vertical column densities measured from MAX-DOAS in Mohali, it was found that the peak daytime O 3 production regime is sensitive to both NO x and VOCs in winter but strongly sensitive to NO x during summer (Kumar, Beirle, et al, 2020 ; Kumar, Pratap, et al, 2020 ). Chen et al ( 2020 ) pointed out that O 3 production is less sensitive to solar radiation in summer compared to winter.…”

Section: Introductionmentioning

confidence: 99%

Interpreting the COVID effect on atmospheric constituents over the Indian region during the lockdown: chemistry, meteorology, and seasonality

Yadav

Trivedi

Ghadai

et al. 2022

Environ Monit Assess

View full text Add to dashboard Cite

Most of the published articles which document changes in atmospheric compositions during the various lockdown and unlock phases of COVID-19 pandemic have made a direct comparison to a reference point (which may be 1 year apart) for attribution of the COVID-mediated lockdown impact on atmospheric composition. In the present study, we offer a better attribution of the lockdown impacts by also considering the effect of meteorology and seasonality. We decrease the temporal distance between the impacted and reference points by considering the difference of adjacent periods first and then comparing the impacted point to the mean of several reference points in the previous years. Additionally, we conduct a multi-station analysis to get a holistic effect of the different climatic and emission regimes. In several places in eastern and coastal India, the seasonally induced changes already pointed to a decrease in PM concentrations based on the previous year data; hence, the actual decrease due to lockdown would be much less than that observed just on the basis of difference of concentrations between subsequent periods. In contrast, northern Indian stations would normally show an increase in PM concentration at the time of the year when lockdown was effected; hence, actual lockdown-induced change would be in surplus of the observed change. The impact of wind-borne transport of pollutants to the study sites dominates over the dilution effects. Box model simulations point to a VOC-sensitive composition.

show abstract

“…During the pre-monsoon season, the entire IGB experience very high aerosol loading attributed mainly because of the frequent occurrence of dust storms (Tiwari et al 2019 ), wheat crop residue burning (Kaskoutis et al . 2014 ; Chauhan et al 2017 ; Rajput et al 2017 ), and extensive anthropogenic activities (Kumar et al 2015 ; Pratap et al 2020 ; Kumar et al 2020 ; Tiwari et al 2020 ). The daily mean mass concentration of the three most common ambient air pollutants, i.e., PM 2.5 , NO 2 , SO 2 (in µg/m 3 ) were obtained from the Centre Pollution Control Board (CPCB: https://app.cpcbccr.com/ccr/#/caaqm-dashboard-all/caaqm-landing/data ) from March to May months of the year 2018, 2019, and 2020.…”

Section: Site Description Dataset and Methodologymentioning

confidence: 99%