'Better air quality to start with this time'

But not much impact on pollution levels

As the second round of odd-even car curbs kicks in from Friday, Delhi’s air quality ranges from ‘good’ to ‘moderate’.

Delhi saw many ‘poor’, ‘very poor’, and ‘severe’ days two to three months ago. But in the previous week and on the first four days of this week, the average air quality – based on Particulate Matter (PM) 10 and PM2.5 concentrations – was in the ‘moderate’ or ‘good’ categories, barring two days when it was ‘poor’..

On Thursday, the levels of PM2.5 and PM10 were 60.1 (good) and 150.4 (moderate) micrograms per cubic metre respectively as per the Union Ministry of Earth Sciences’ System of Air Quality and Weather Forecasting and Research (SAFAR) Index.

The prescribed standards are 60 and 100 respectively. However, experts say this is “nothing new” for the month of April.  

“The temperatures rise and winds are moderate at this time of the season, bringing down pollution levels,” said scientist and SAFAR Project Director Gufran Beig.

Even the prediction for next three days (excluding impact of odd-even, if any) according to SAFAR is in the moderate range.

The data is the average air quality of the city. However, in individual areas, the ambient air quality was recorded as ‘moderate’ or ‘poor’.

“There are two main factors for pollution – weather and emissions. In winters, weather is the major contributor, whereas in summers emission plays the lead role and weather is favourable,” Beig said.

Sumit Sharma, Fellow at The Energy and Resources Institute (TERI), also said that there is low concentration of pollutants in summers.

“Summers tend to show lower values of PM2.5 because of meteorological factors where we have higher wind speed and then there is a phenomenon called thermal diffusion which allows the pollutants to go up in the atmosphere,” he said.

Experts believe that though there would not be a “huge” impact on pollution levels due to odd-even, it is possible that this time around the impact of the scheme, if any, would be more visible.

“In winters, any reduction due to odd-even is difficult to detect but this time detection can be stronger,” Beig said.

However, Sharma added that no one should expect a big impact due to the road rationing scheme as contribution of private cars in the overall inventory is not huge.

“Had the government put women and two-wheelers in the exemption category, there would have been better results. There would be an impact on congestion but we cannot think of reducing pollution drastically just through private cars,” he added.

TERI will carry out a trend analysis of three pollutants (PM10, PM2.5, and NO2) at nine locations – Mandir Marg, RK Puram, Punjabi Bagh, Anand Vihar, Bahudargarh, Lodhi Road, Ghaziabad, Gurgaon, and Noida, till April 30, to assess pre and post odd-even driver air quality scenario.

“We are keeping our monitors and models ready to attribute whatever impact odd-even can bring,” Sharma said.

Meanwhile, the Delhi Pollution Control Committee (DPCC) will monitor air quality at 109 locations, including 20 residential areas, 15 industrial areas, and border areas.