NEW DELHI: Data released recently by System of Air Quality and Weather Forecasting Research (SAFAR) under the ministry of earth sciences shows the air quality in September has steadily worsened since 2011.
This is worrying because September is a good time to gauge the impact of vehicles, factories, etc, on overall air quality.
SAFAR's data also shows that every year air pollution levels in October climb higher than in September as the temperature starts falling. "September is sliced between a rainy period and the onset of winter. It is usually a reflection of the impact of local emissions from various sources," said Gufran Beig, project director, SAFAR.
The monthly PM2.5 (fine, respirable pollution particles) average for September rose 63% from 54 micrograms per cubic metre in 2011 to 88 micrograms per cubic metre in 2015. The major sources of air pollution in Delhi are transport, industries, biomass burning and dust. Transport is the biggest contributor, SAFAR's research shows.
Levels of fine, particulate pollution in October are always higher than in September and are highly influenced by weather, which is why there is no consistent trend in October's PM2.5 levels. For instance, this October, PM2.5 levels were the lowest compared with the last four years. The monthly average PM2.5 was 119 micrograms per cubic metre this time, as against 151 micrograms per cubic metre last year.
"Pollution levels, October onwards, are mainly controlled by lowering of the boundary layer (lowest part of atmosphere) due to rapid fall in temperature and onset of winter. The boundary layer this year has not fallen too much yet," Beig added.
