Air quality improves slightly on second day of odd-even

Air quality in Delhi improved and was logged between moderate and poor levels as fine respirable pollutants tapered off considerably across the city on the second day of the odd-even car-rationing scheme. Eight-hour average of Ozone, a gaseous pollutant, also dipped below 40 parts per billion (ppb), a sharp drop from yesterday and the day before. Its eight hour notified average safe limit is 100 micrograms per cubic metre.

The eight monitoring stations of the Centre’s SAFAR (System of Air Quality and Weather Forecasting and Research) put air quality between moderate and poor with the forecast being the same.

Delhi government said that as per initial trends, the scheme, under which cars with odd and even number plates run on alternate days, will have a “positive impact” on the city’s air quality.

“PM 2.5 levels were found within permissible limit (below 60) at 40 out of 74 locations and PM 10 levels at majority of locations were recorded below the level of 200 (monitored on April 15). Concrete assessment will be made after assessing the data of four-five working days,” an official statement said.

Yesterday, air quality had dipped owing to pollutants-laden wind blowing from the northwest direction.

SAFAR’s data showed that 24-hour-average of PM 2.5 was at 106 micrograms per cubic metre (ug/m3) at 6 PM today. The same was over 120 ug/m3 on April 15 around the same time.

The safe levels of PM 2.5 and PM 10 are 60 and 100 ug/m3 respectively, anything beyond which are considered hazardous for the respiratory system.