EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Spatio-temporal variations of PM2.5 and Respiratory Deposition Dose (RDD) before and during different COVID-19 lockdown phases at Delhi, India

Sadaf Fatima1,2, Ajit Ahlawat3, Sumit Mishra1,2, Vijay Soni4, and Randeep Guleria5
Sadaf Fatima et al.
  • 1CSIR-National Physical Laboratory, Environmental Sciences and Biomedical Metrology, India (
  • 2Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh-201002, India
  • 3Leibniz Institute for Tropospheric Research (TROPOS), Permoserstraße, Leipzig-04318, Germany
  • 4Indian Meteorological Department, New Delhi-110037, India
  • 5All India Institute of Medical Sciences, New Delhi-110029, India

Present study explores pre-lockdown (1st January-24th March, 2020) and during lockdown (25th March-20th June, 2020) air quality changes in PM2.5 along with meteorological effects at megacity- Delhi (28.7041°N, 77.1025°E). Alipur (Rural), Okhla (Industrial) and Pusa Road (Traffic dominant area) experienced mean concentrations (S.D.) of PM2.5 as 87.56(±54.06), 124.45(±73.49) and 62.14(±58.64) µg/mbefore lockdown(BL; 1st January-24th March, 2020), while for Lockdown1(L1; 25th March-14th April, 2020), PM2.5 decreased drastically as 39.26(±16.31), 38.01(±15.16) and 31.03(±12.79) µg/m3 and gradually increased during Lockdown2(L2; 15th April-3rd May, 2020), Lockdown3(L3; : 4th May-17th May, 2020), Lockdown4(L4; 18th May-31st May, 2020), respectively. Percentage decrease in PM2.5 (-69.46%) correlated with outdoor activities of percentage decrease (-70 to -80%) in L1, from BL phase. Exposure assessment study showed, mean Respiratory Deposition Dose-RDD (S.D.) (µg/hr) for fine particles [Particle diameter (Dp) =0.5 µm] for walk and sit mode during BL, as 27.22(±13.53) and 9.90(±4.91) for Alipur, 30.55(±18.04) and 11.11(±6.56) for Okhla, and 28.67(±14.39) and 10.43(±5.23) for Pusa road, and decreased during L1 as 9.64(±4.00) and 3.50(±1.46) for Alipur, 9.33(±3.72) and 3.39(±1.35) for Okhla, and 7.62(±3.14) and 2.77(±1.14) for Pusa road, respectively. Delhiites were exposed to more fine RDD(walk/sit) before lockdown than during lockdown phases. People in sit mode found less exposed to fine RDD, in comparison to walk condition. The people living indoors were affected by outdoor RDD exposure with windows open condition, while exposed to different indoor pollution sources with windows closed condition during lockdown. Authors suggest avoid use of closed conditioned indoors and ACs; frequent opening of windows to lower the RDD and to minimize the COVID-19 virus transmission via particulates.

Keywords: PM2.5, RDD, COVID-19.

How to cite: Fatima, S., Ahlawat, A., Mishra, S., Soni, V., and Guleria, R.: Spatio-temporal variations of PM2.5 and Respiratory Deposition Dose (RDD) before and during different COVID-19 lockdown phases at Delhi, India, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15349,, 2021.

Corresponding displays formerly uploaded have been withdrawn.