For the first time in this month, the air quality was recorded "good" on in the national Capital. Values of both the Particulate Matters — PM 2.5 and PM10 were recorded at 84 and 117 microgramme per cubic metres (µg/m3) respectively.
With the period of stubble burning coming to an end coupled with cold wave, air quality in the Capital turned to "good". NAAQI recorded air quality in good category on Monday morning. Also the values of noxious gases and other harmful pollutants were recorded "relatively low on the 17th day of observation.
"Although values are still on the higher side as compared to the safe limit of 600 and 100 for PM 2.5 and PM 10 but it is good time for Delhiites to breath fresh air as the air quality is dare better now, an official said. Fortunately, there is no occurrence of thermal inversion in Delhi's atmosphere and good wind speed is another factor for cleaning air by settling down deadly particle - PM 10", he added.
System of Air Quality Forecast and Research (SAFAR), Ministry of Earth Sciences has marked Delhi's map with yellow colour, it further means that air quality is good and moderate. SAFAR in its three days of pollution forecast also mention that air quality will moderate for next three days.
Air pollution in Delhi arises in winters. And factors contributing to deteriorate air are - Vehicular Emission, Burning of agriculture waste in the neighboring States and, massive dust storms from across West Asia, Pakistan, Rajasthan and the Thar desert.
Analysis of three-year data (2013-2015) on PM 2.5 in Delhi gathered by the Central Pollution Control Board (CPCB), from 10 different locations in the city reveals a systematic wave-like pattern: Air pollution peaks every winter from October to January.
It is important to mention here that, this year, in mid-December, air quality has improved remarkably. Pollutant values were recorded between 200 and 250 µgm-3 for PM 2.5 and 342-450 µgm-3 for PM 10 in 2016, however, this year, a sharp dip in concentrations of both pollutants were recorded.
As per experts, weather is central to Delhi's air quality. At present, Delhi's wind speed is 12-22 mm per hour and absence of fog has defeated the reaction between fog and pollutants.
Experts also believe that besides weather and good wind speed, deep forest surrounding the city can control the air pollution. A massive afforestation programme may help in long run, they said.