It appears you don't have support to open PDFs in this web browser. To view this file, Open with your PDF reader
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.
You have requested "on-the-fly" machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Show full disclaimer
Neither ProQuest nor its licensors make any representations or warranties with respect to the translations. The translations are automatically generated "AS IS" and "AS AVAILABLE" and are not retained in our systems. PROQUEST AND ITS LICENSORS SPECIFICALLY DISCLAIM ANY AND ALL EXPRESS OR IMPLIED WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES FOR AVAILABILITY, ACCURACY, TIMELINESS, COMPLETENESS, NON-INFRINGMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Your use of the translations is subject to all use restrictions contained in your Electronic Products License Agreement and by using the translation functionality you agree to forgo any and all claims against ProQuest or its licensors for your use of the translation functionality and any output derived there from. Hide full disclaimer
Details
1 Rajdhani College, University of Delhi, Radio and Atmospheric Physics Lab, New Delhi, India (GRID:grid.8195.5) (ISNI:0000 0001 2109 4999)
2 University of Delhi, Department of Physics and Astrophysics, New Delhi, India (GRID:grid.8195.5) (ISNI:0000 0001 2109 4999)
3 Jawaharlal Nehru University, School of Environmental Sciences, New Delhi, India (GRID:grid.10706.30) (ISNI:0000 0004 0498 924X)
4 Aryabhatta Research Institute of Observational SciencES (ARIES), Nainital, India (GRID:grid.440527.0) (ISNI:0000 0001 1019 6308)
5 Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan (GRID:grid.410588.0) (ISNI:0000 0001 2191 0132)
6 Nagoya University, Institute for Space-Earth Environmental Research, Nagoya, Japan (GRID:grid.27476.30) (ISNI:0000 0001 0943 978X)
7 Nagasaki University, Faculty of Environmental Science, Nagasaki, Japan (GRID:grid.174567.6) (ISNI:0000 0000 8902 2273)
8 Kobe University, Graduate School of Maritime Sciences, Kobe, Japan (GRID:grid.31432.37) (ISNI:0000 0001 1092 3077)
9 Japan Meteorological Agency, Meteorological Research Institute, Tsukuba, Japan (GRID:grid.237586.d) (ISNI:0000 0001 0597 9981)
10 Research Institute for Humanity and Nature, Kyoto, Japan (GRID:grid.410846.f) (ISNI:0000 0000 9370 8809)
11 Research Institute for Humanity and Nature, Kyoto, Japan (GRID:grid.410846.f) (ISNI:0000 0000 9370 8809); Nara Women’s University, Faculty of Science, Nara, Japan (GRID:grid.174568.9) (ISNI:0000 0001 0059 3836)