These days, the word CORONA has created fear in everyone. Almost entire world is now familiar from the name COVID-19 or WCOVID-19. COVID-19 stands for COrona VIrus Disease outbreak in 2019 or Wuhan COrona VIrus Disease outbreak in 2019 (WCOVID-19). According to one of chinse news, this disease was started on 17th November 2019 from Wuhan. Then it starts spreading exponentially in nearby cities of China. In order to avoid spreading of COVID-19, on 23 January 2020, the central government of China imposed a lockdown in Wuhan and other cities in Hubei province. The incident was commonly referred to in the media as the "Wuhan lockdown".
This National emergency in China had potential impact on its commercial activities, which draw attention of National Center in Big Data and Cloud Computing (NCBC) Environment Monitoring unit(EMU) UET Peshawar to investigate in its impact on environment. NO2 is consider one of major air pollutant which exists near earth (troposphere). We processed Pre-COVID19 and during COVID19 datasets of Sentinel-5p satellite in Google Earth Engine. Figure 1 shows Pre-COVID19 NO2 in troposphere of China and Figure 2 shows the extent of NO2 during lockdown. Due to complete lockdown of Wuhan, its troposphere shows an average concentration of 24×10^15 molec/cm2 NO2, while during Lockdown NO2 Concentration fall to 3.5×10^15 molec/cm2 , which is 87.1% decrease. Nitrogen dioxide is an important air pollutant, which can have significant impacts on human health. The major source of nitrogen dioxide is burning of fossil fuels: coal, oil and gas and manufacturing industries. Its major decrease after outbreak of corona in China and Italy shows that it has positive impact on environment. Such a drastic decrease shows that in Wuhan there were very fewer human activities that cause damage to the environment on a global scale (anthropogenic activities). During Lockdown Period Chines government successfully reduced COVID19 patients from thousands to a single digit.
Fig.1 - Pre- COVID19(2019-11-14 to 2020-01-15) Averaged NO2 over China
Fig.2 - During Lockdown(2020-01-23 to 2020-03-15) Averaged NO2 over China
After China, Italy is considered as most affected country. Figure 3 shows Average concentration of NO2 in Italy troposphere during 1st February to 15th March 2020. The Pre-COVID19 and during Post-COVID19 Average concentration of NO2 in Italy troposphere is shown in Figure 3a and Figure 3b respectively. Before COVID19 outbreak, average of 21×1015 molec/cm2 NO2 concentration was noticed over Milan and its nearby cities. On 9th March 2020, the government of Italy under Prime Minister Giuseppe Conte imposed a national quarantine, restricting the movement of the population except for necessity, work, and health circumstances, in response to the outbreak of COVID-19 in the country. During the lockdown period (2020-03-09 to 2020-03-15) averaged NO2 concentration is estimated 11×10^15 molec/cm2 , which is 47.7% decrease. It clarifies that most of NO2 in Italy also comes from anthropogenic activities like burning of biomass and fossil fuels.
Fig.3 - Averaged NO2 over Italy During 2020-02-01 to 2020-03-15
All figures have been generated using Google Earth Engine.