Not only the levels of particulate matters but the high concentration of harmful gases in the national Capital’s air is also increasing pollution level. The gas concentration of benzene, sulfur dioxide and nitrogen oxide were observed “abnormally high” than the prescribed standards on the real time ambient air metre of Delhi Pollution Control committee (DPCC) on Wednesday
Gopal Krishan, environmentalist with Toxic Watch Alliance (TWA), said human exposure to harmful gases like benzene is associated with a range of acute and long term adverse effects and disease, including cancer and aplastic anaemia. “Benzene is highly volatile, and exposure occurs mostly through inhalation,” said the environmentalist.
The prescribed standards of benzene gas is 5 µg/m3 while in RK Puram area it was observed 7 µg/m3 and the level of nitric oxide was 56 .21 µg/m3 while prescribe standard is 50.35 µg/m3only.
The environmentalists and health experts in Delhi have already raised an alarm over the noxious air in city atmosphere and said due to the presence of harmful gases, those living in Delhi stand the risk of contacting respiratory and cancer like diseases.
“Besides burning of biomass and vehicular emissions, industry pollution is also playing a major role in polluting the highly contaminated air. The continuous and repeated exposure to air is very vulnerable,” said an health expert.
In Anand Vihar area, the level of nitrogen dioxide was 135.3 µg/m3 while Prescribed Standards is 80 µg/m3 and oxides of nitrogen was monitored 318.7 µg/m3 however PS is 145 µg/m3 only, said a DPCC official.
As Delhi has twenty per cent forest area the problem can only be overcome with more plantations, said the environmentalists. Taking cognisance of the rising gas volume in the city air, a senior Delhi Government official said efforts were on to expand the green cover and according to the current data, the target could be achieved by 2021.
In seven out of 10 monitoring stations of the Central Pollution Control Board, PM 2.5, particulate matter having the size equal to or less than 2.5 micron, came out to be the major pollutant.
However, in Anand Vihar, the most polluted spot in the city, PM 10 had more presence. PM 10 is the particular matter having the size equal to or less than 10 micron.
The Delhi Pollution Control Committee’s (DPCC) real time monitoring showed PM 2.5 and PM 10 at 191 and 611 respectively while RK Puram had the corresponding figures at 220 and 458 at around 12.30 PM.
Meanwhile , the visibility in the city improved further and oscillated between 500 and 1,700 metres in the city including at IGI airport. It had fallen sharply on November 30 and has risen since then.
IMD director BP Yadav attributed it to cloudy conditions.
“Whenever skies are cloudy, dense fog does not form as a result of which the visibility is relatively better. Usually low temperatures in the night, smoke, absense of wind and high moisture levels over a period of say 48 hours or more leads to accumulation of particulate matter,” he said.
However, he added that low visibility conditions are likely to persist over the next few days. On Tuesday, the visibility was 1,500 m at the maximum and the minimum was 200.
Air Quality Index (AQI) of System of Air Quality and Weather Forecasting and Research (SAFAR) stations, located across the city, also hovered between very poor and poor. Dhirpur station’s PM 2.5 and PM10 AQI were 392 and 369 at 12.55 PM.
‘Very poor’ signifies PM 10 and PM 2.5 levels between 351 and 420 and 211 to 252 microgram per cubic metre. ‘Severe’ is declared when PM 2.5 and PM 10 cross 253, 421 micro gram per cubic metres respectively.
Permissible levels of particulate matter 2.5 and PM 10 are 60 and 100 micrograms per cubic metre respectively and consistent exposure to anything beyond that can harm the respiratory system as the particles embed themselves deep inside the lungs.
These respirable particulate matters, a product of vehicle emissions, burning of waste, industrial plumes, especially PM 2.5 is considered by the World Health Organisation (WHO) as the best indicator of the level of health risks from air pollution.
While Delhi chokes, other cities such as Mumbai and Bangalore had much lesser levels of pollution with the air quality being recorded between moderate to poor.