Air pollution curve flattens in Delhi-NCR due to lockdown impact
Clear blue skies, a very rare sight in Delhi-NCR has become the norm after the lockdown was announced on March 25. This is now supported by data also.
A new analysis by Centre for Science and Environment said morning and evening peaks in PM 2.5 (fine, respirable pollution particles) have flattened out. The reduction in nitrogen dioxide (NO2) concentrations is even more pronounced because the major source of NO2 emissions are vehicles and industries.
The hourly pollution trend in Delhi, Gurugram, Faridabad, Noida and Ghaziabad analysed by CSE used to be majorly influenced by traffic peaks in morning and evening which is not seen anymore.
“This analysis brings out the pronounced effect of traffic on hourly pollution trend and on daily exposures to toxic vehicular pollution. With traffic minimized hourly trends plummet. This is sharply evident in NO2 trends,” the analysis released on Saturday said.
Meanwhile, the regional weather forecasting centre in Delhi released historical data for the maximum temperature recorded in April which ranges from 39.6 degree C in 1994 to 43.7 degree C in 2010. “Data analysis since 1992 shows maximum temperature over Delhi reaches 40 degree C during April 17 to 20. If temperature and humidity play a role in reduction of transmission of the virus (SARS-CoV-2) we will be able to see the trends in April. But things will be different if people use air conditioning indoors,” said Kuldeep Shrivastava, head, RWFC.
For this analysis following days have been considered by CSE:
• Regular = Average of 18 and 19 March 2020
• Lockdown = Average of 25 and 26 March 2020
• Janata curfew = Average 22 March 2020