Diwali this year caused more air pollution, but made less noise

After the severe smog witnessed post Dussehra, air pollution levels in the national capital rose again after Diwali. Ambient air quality monitoring by the Central Pollution Control Board (CPCB) during Diwali this year showed that air pollution levels have increased sharply in Delhi as compared to last year. However, the noise levels showed a decreasing trend. CPCB attributes the decreasing trend in noise levels to bursting of less noisy crackers and high pollution levels to adverse meteorological conditions.

CPCB’s ambient air quality monitoring at seven locations—Pragati Maidan, Pitampura, Sirifort, Janakpuri, Nizamuddin, Shahzada Bagh and Shahdara—showed very high PM10 levels. It has not only doubled over previous year’s level but also exceeded the 24 hourly standards of 100 microgramme per cubic metre (µg/m³) by 9 to 10 times. Last year the pollutant exceeded the standard four to five times. PM10 levels ranged from 748 to 951 µg/m³ compared to 416 and 635 µg/m³ during last Diwali (see table).

According to CPCB, adverse meteorological conditions, such as decrease in temperature, mixing height and wind speed, contributed to increased PM10 values this year. High air pollution levels have an adverse impact on public health and aggravate respiratory ailments. Studies conducted have already established the association of PM levels to adverse health outcomes. Children, the elderly and people suffering from respiratory ailments are the most vulnerable. Doctors report an increase in the number of respiratory cases every year with the onset of winter.

Not only PM10 levels, nitrogen dioxide (NO2) levels have also increased at all locations. However, the NO2 levels were found to be within the standard (80 µg/m³), except at the Pragati Maidan monitoring station. Sulphur dioxide (SO2) levels increased at three locations, but were found to be within limit at all locations. The peak level was registered at Janakpuri at 63 µg/m³. Vehicular exhaust fume is the prime contributor of PM and NO2 pollution. This, along with bursting of crackers, aggravated pollution levels during Diwali.

The Delhi Pollution Control Committee, which monitors ambient air quality of Delhi at 6 locations, also found high pollution levels.

 

Call to implement new action plan

It is high time that Delhi acts immediately and aggressively to reduce its daily pollution levels, says Anumita Roychowdhury, head of the air pollution and clean transportation unit of Delhi non-profit Centre for Science and Environment. Especially in view of the fact that PM and the NO2 levels have increased by 47 per cent and 57 per cent respectively between 2000 and 2011. The city has lost the air quality gains it achieved from first generation actions. It now needs to implement second generation action plan.

 

The potential of lower vehicular emissions in Indian cities

Multi-pollutant emissions inventory of National Capital Region of Delhi

Status of vehicular pollution control programme

Level of air pollution in Delhi

Urban outdoor air pollution database