JOIN USEven as the Delhi government’s odd-even experiment entered its fourth day, the capital saw a spike in the levels of PM 10 and PM 2.5 Monday, with the overall average air quality being recorded in ‘very poor’ category.
On the System of Air Quality and Weather Forecasting and Research (SAFAR) website, both Particulate Matter (PM) 10 (particles below 10 microns in diameter) and PM 2.5 (below 2.5 microns and capable of entering human lung and blood tissues due to smaller size) were recorded at 397.1 and 249.9 respectively, much above the prescribed limits of 100 and 60 respectively. There was an approximate increase of 16 per cent in the PM 2.5 levels since Sunday’s average. The hourly update of SAFAR showed an upward trend of PM 10 and PM 2.5 concentration since morning. At 11 am, the PM 2.5 level was 237 micrograms per cubic metre, it increased to 244 at 2 pm, 253 at 4 pm and 266 at 7pm.
The government said that it took samples of PM 2.5 and PM 1 (being monitored first time in India) in some areas in the city and its results show that pollution level is down as there was less emission due to fewer vehicles on roads. However, experts suggest that weather related factors like calm winds have played truant. The officials of the weather department said that on Monday there was “hardly” any wind movement, compared to Sunday which saw westerly winds movement.
According to Dr R K Jenamani, Head, IGIA MeT, “Wind is the single major factor which affects local pollution irrespective of other changes. Stronger winds sweep away many pollutants while light winds or no winds hardly remove it”.
Even a fall in the maximum temperature could be the reason behind this as cooler the temperature, lower the boundary height and higher the air pollution. At 7.30 pm, the Delhi Pollution Control Committee’s (DPCC) monitoring station at Mandir Marg recorded PM 2.5 level of 307 microgram per cubic metre, as compared to 176 at 7 pm on the same day in 2015.
Similarly, the monitoring station in R K Puram showed PM 2.5 of 530 at 7:30 in the evening, compared to 182 at 7:05 pm in 2015.
“The wind speed has considerably reduced from 5-6 km per hour to almost 2-3 km per hour in the past one week.