Ozone pollution has reached alarming levels in Delhi and the National Capital Region (NCR) which are in the grip of a multi-pollutant crisis, adding to the public health risk, the Centre for Science and Environment (CSE) said on Monday.
CSE noted that due to high pollution levels and growing heat stress owing to climate change, the ozone level is frequently exceeding the standards and rising to ‘poor’ and ‘very poor levels’ – as classified by the National Air Quality Index (NAQI).
Even before the health risk from particulate matter could be addressed, deadly ozone has raised its ugly head in Delhi and NCR.
Without a time-bound implementation strategy and preventive action, this can deepen into a serious public health crisis. This will spare neither the rich nor the poor.Anumita Roy Chowdhury, head of CSE’s air pollution programme
‘Days With Unhealthy Levels Of Ozone On The Rise’
CSE analysed the real-time air quality data available from the key monitoring locations of Delhi Pollution Control Committee for the summer months of 2016 and 2017.
CSE's analysis showed that heat waves and sunshine have increased the frequency of days with unhealthy levels of ozone and this has become worse this summer.
It said ground-level ozone is not directly emitted by any source and this is formed when oxides of nitrogen (NOx) and a range of volatile gases, primarily from vehicles and other sources, are exposed to each other in sunlight.
Warm and stagnant air increases the formation of ozone. Ozone is extremely hazardous for human health.Centre for Science and Environment
As summer progressed from February to May this year, the ozone built up rapidly and the number of days exceeding the ozone standard increased, the analysis found.
The share of days violating the 8-hour Central Pollution Control Board (CPCB) standard of 100 microgramme per cubic metre in February was 12 percent – this increased to 19 percent in March, 52 percent in April and finally a whopping 77 percent in May, the analysis found.
“On several occasions and several locations, very high peak levels – 3.4 times the standards,” CSE said.
This, it said, is of serious concern as even short duration exposure to high ozone levels can cause great harm.
The analysis found that not only have the total numbers of days that have violated the standards increased this year, the severity of the problem has also grown.
This summer (April-May), 8 percent of days are in ‘very poor’ category – which is up to 4.2 times the standards, as opposed to 4 percent during the same months in 2016.
Due to higher temperature and solar radiation, ozone concentration has also increased, CSE said.
In April 2017, as the temperature increased from 27°C on 9 April to 32°C on 14 April, the daytime ozone levels increased by 134 percent or 2.34 times – rising from 90 to 211 microgramme per cubic metre.
Are Your Localities Safe?
Residential areas of RK Puram and Punjabi Bagh have high ozone concentrations – much higher than the commercial and transport hub of Anand Vihar. This is a very serious health concern, it said.
Ozone aggravates respiratory problems, especially chronic obstructive pulmonary disease (COPD).
The new burden of disease study from Health Effect Institute has shown that early deaths due to ozone have jumped by 148 percent in India, the body said.
"Delhi and NCR need much higher degree of health protection for all and especially the high risk groups including the elderly, children, outdoor workers and people with asthma and lung disease.”
Cost of inaction can be very high. Government must have implementation strategy for priority measures in place before the next winter.Centre for Science and Environment
What Needs To Be Done
- CSE recommended finalisation and implementation of pollution source-wise comprehensive action plan directed by the Supreme Court in Delhi and NCR.
- To include targeted reduction of gaseous emissions from vehicles, industry and power plants
- Stringent measures are needed to reduce nitrogen oxide and a range of volatile hydrocarbons.
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