The Impact of Lockdown on eBC Mass Concentration over a Semi-arid Region in Southern India: Ground Observation and Model Simulations

Abstract

In the present study, we focused on the impact of lockdown on black carbon (eBC) mass concentrations and their associated radiative implications from 01 st March to 30 th June 2020, over a semi-arid station, i.e., in the district of Anantapur in Southern India. The mean eBC mass concentration was observed before lockdown (01 st -24 th March 2020) and during the lockdown (25 th March to 30 th June 2020) period and was about 1.74±0.36 and 1.11±0.14 µg m -3 , respectively. The sharp decrease (~35%) of eBC mass concentration observed during the lockdown (LD) period as compared with before lockdown (BLD) period, was mainly due to the reduction of anthropogenic activities and meteorology. Furthermore, during the entire LD period, the net composite forcing at the top of the atmosphere (TOA) and at the surface (SUR) varied from -4.52 to -6.19 Wm -2 and -22.91 to -29.35 Wm -2 , respectively, whereas the net forcing in the atmosphere (ATM) varied from 17.27 to 23.16 Wm -2 . Interestingly, the amount of energy trapped in the atmosphere due to eBC is 11.19 Wm -2 before LD and 8.56 Wm -2 during LD. It is concluded that eBC contributes almost 43 -50% to the composite forcing. As a result, the eBC atmospheric heating rate decreased significantly (25%) when compared to before lockdown days to lockdown days.

Compensatory effect of biomass burning on black carbon concentrations during COVID-19 lockdown at a high-altitude station in SW India

“… Pre-Lockdown Concen. Changes in % HACPL, Mahabaleshwar 1378 m Rural 28th March to May 31, 2020 1.23 ± 0.68 2.20 ± 1.12 44% reduction Present study Delhi 216 m Urban 25th March to April 14, 2020 1.73 7.93 78% reduction Goel et al (2021) Bengaluru 920 m Urban 24th March to April 14, 2020 1.69 ± 0.04 4.33 ± 0.15 60% reduction Ajay et al (2021) Ahmedabad 55 m Semi-arid 25th March to May 31, 2020 2.2 ± 0.7 3.5 ± 1.3 35% reduction Rajesh and Ramachandran (2022) Anantapur 335m Semi-arid 25th March to 30th June 2020 1.11 ± 0.14 1.74 ± 0.36 35% reduction Palle et al (2021) …”

“…As shown in Table 1 , the highest reduction in BC mass concentration was observed for megacities (urban locations), such as Delhi (78%; Goel et al, 2021 ) and Bengaluru (60%; Ajay et al, 2021 ). Rural and semi-arid regions tended to show a lesser reduction in BC mass concentration due to lockdown (Anantapur: Palle et al, 2021 ; Ahmedabad: Rajesh and Ramachandran, 2022 ). A possible reason could be that the BC mass concentrations in urban locations were mainly driven by the extent of fossil fuel emissions, which were minimal during the lockdown.…”

“…Due to the lockdown, a significant decrease in vehicular movement, construction and industrial work, and other commercial activities was observed across the country, reducing PM 1 , PM 2.5 , and PM 10 concentrations. Many studies have discovered that the implementation of lockdown in India and other parts of the world has resulted in a significant reduction in BC and other pollutant mass concentrations ( Ajay et al, 2021 ; Goel et al, 2021 ; Jafar and Harrison, 2020 ; Manohar et al, 2021 ; Milinković et al, 2021 ; Palle et al, 2021 ; Rajesh and Ramachandran 2022 ; Rathod et al, 2021 ; Shen et al, 2021 ). Conversely, recent studies over the Indian subcontinent using satellite data ( Ratnam et al, 2021 ; Bhawar et al, 2021 ; Pandey and Vinoj, 2021 ) revealed that the central Indian region showed an increasing trend in aerosol optical depth (AOD) during the lockdown period, although there was a decrease over the Indo-Gangetic Plain (IGP) region and other parts of India.…”

Pandemic‐induced fear and government policy response as a measure of uncertainty in the foreign exchange market: Evidence from (a)symmetric wild bootstrap likelihood ratio test

“…Previous studies have analysed the impact of lockdown on the environment (Garg et al, 2020; Jain & Sharma, 2020; Krishan et al, 2021; Kumari & Toshniwal, 2022; Mohite et al, 2022; Palle et al, 2021; Sahoo et al, 2021; Saxena & Raj, 2021; Singh & Chauhan, 2020; Soni, 2021), employment and labour markets (Abraham et al, 2022; Bhatt et al, 2021; Deshpande, 2020; Kapoor, 2020; Mamgain, 2021; Vyas, 2020), education (Kapasia et al, 2020; Ravi, 2020; Singh et al, 2022), mental health and lifestyle (Das et al, 2021; Grover et al 2020; John & John, 2021; Nilima et al, 2021; Narayanan et al, 2020), and tourism (Chandel et al, 2021; Jaipuria et al, 2021; Kumar, 2020; Patil & Naik, 2020; Seraphin & Dosquet, 2020; Sharma et al, 2020; Singh et al, 2021). There has been little research on the possible influence of lockdowns on the Indian foreign exchange market.…”