Air quality in the national Capital on Friday has recorded “very poor” as National Ambient Air Quality Index (NAAQI) marked the index “red”.
The System of Air Quality and Weather Forecasting and Research (SAFAR), a unit of Ministry of Earth Sciences (MoES), in its advisory cautioned people to avoid all physical activities outdoor and move activities indoors. Also, asthma suffering people have been suggested to keep relief medicine handy.
“Stop outdoor activity at early morning and after sunset times. Avoid prolonged or heavy exertion,” quoted SAFAR health advisory. The values of both the pollutants — Particulate Matter (PM) 10 and PM 2.5 were recorded at 8 pm 270 and 125 respectively in Micro Cubic Per Gram (µgm-3).
Also, SAFAR has forecast air quality “very poor” till Sunday. Concentrations of both the pollutants (PM10, 2.5) for next three days are — 270 -125, 297-138 and 311-144 (µgm-3). This further means the concentration of pollutants in air is abnormal. Notably, the permissible limits of both the pollutants are 100 and 60 micro cubic per gram.
Importantly, air quality during day time measured slightly improved on index due to moderate rainfall in a few pockets in Delhi.
However, the other Air Quality Index - Delhi Pollution Control Committee (DPCC) and US embassy marked values high for RK Puram, Anand Vihar, Punjbai Bagh , India Gate area.
On Wednesday and Thursday, the air quality had deteriorated to the very poor category, alarming authorities who were planning to roll out more stringent measures to combat pollution.
An AQI between 0 and 50 is considered “good”, 51 and 100 “satisfactory”, 101 and 200 “moderate”, 201 and 300 “poor”, 301 and 400 “very poor” and 401 and 500 “severe”.
A senior official said the reason for improvement of air quality was the rainfall Thursday which lashed parts of the national Capital, cleansing the air of the pollutants.
The PM10 level (presence of particles in the air with a diameter of less than 10 micrometres) in Delhi stood at 253 and the PM 2.5 level was recorded at 110 in day time (around 4 pm).
On Thursday, the PM2.5 (presence of particles in the air with a diameter of less than 2.5 micrometres) touched a new high at 158. The PM2.5, also called “fine particulates,” can be a matter of more serious health concern than PM10.
A Central Pollution Control Board official said a number of factors were responsible for the deteriorating air quality, including vehicular pollution and construction activities.
The estimated total emission of PM2.5 for Delhi-NCR domain is calculated to be around 107.786 Gg/yr in 2018.
Transport sector and industrial sector are playing major role in PM2.5 emission by contributing around 42.230 Gg/yr and24.10 Gg/yr respectively to the total emission.
Windblown dust is contributing around 19.50 Gg/yr followed by residential sector 6.2 Gg/yr and thermal power plants (3.34 Gg/yr). High emission of PM2.5 in the range of 10-50 tonne/yr is found over eastern, central, some part of southeastern part of Delhi-NCR, which includes major dense roads network and industrial and residential zones.
Emission of the order of 200-1000 tonne/yr is found over industrial zone next to major roads. Large point sources like thermal power stations and WSM plants are some of other highly emitted zone. Western and northern region of Delhi shows comparatively lower value of PM2.5 emission in the range of 0.6-8.0 ton/yr due to large agricultural lands, less number of industries followed by low population density leading to minimum emission.
The residential emission has reduced drastically due to penetration of LPG connection in slums (95 per cent) and household. The MSW related pollution is emerging as new challenge to tackle air quality issue in Delhi.
