Delhi government will check air quality at 119 locations during the second phase of odd-even plan. (File photo)
With second phase of the odd-even scheme set to roll out from April 15, experts will be keeping a close eye on gaseous pollutants such as ozone which spikes during the summer season, while Centre's SAFAR will be monitoring ultra-fine particles.
Fine respirable particles such as PM 2.5, which was closely monitored during the January phase of the car-rationing plan, will be on the "lower side" this time round due to meteorological factors, said Anumita Roychowdhury of the Centre for Science and Environment (CSE).
Gufran Beig, Project Director at Pune-based SAFAR (System of Air Quality and Weather Forecasting and Research), said that it will put hourly updates on ozone this time and also collect data on ultra-fine particles PM 1, tinier and deadlier than PM 2.5.
SAFAR has eight air-quality monitoring stations in Delhi and one each in Gurgaon and Noida.
"The boundary layer, which traps pollutants, come close to the earth's surface during the winter months keeping PM 2.5 and PM 10 high. But the pollutants profile change during summer," Mr Beig said.
Ms Roychowdhury explained that reducing vehicles on the road may mitigate the hazardous effects of ozone, which impair lung functioning on prolonged exposure. Its one hour notified average safe limit is 180 micrograms per cubic metre.
"We will be closely looking at the scheme's impact on gaseous pollutants such as ozone, oxides of nitrogen and sulphur and carbon monoxide which add to the PM 2.5 load, on being released in the air," she said.
Meanwhile, Delhi government will check air quality at 119 locations, including 21 areas on the city's periphery and its seven major entry points.
The government had plans to check the level of PM 1 during the first phase of the scheme itself, although it did not share any such findings later. This time, it does not have any plan to monitor the ultra-fine particles.