Ozone levels have shot up in Delhi and the gas is causing severe health problems for asthmatics and those with respiratory illnesses in the city, according to a recent study by the Centre for Science and Environment (CSE).
Analysis of real-time air quality data from key monitoring stations of the Delhi Pollution Control Committee (DPCC) from January to early June shows the rapid build-up of ozone and frequent deviation from pollution standards this summer.
“Ozone levels must be curbed at the early stages with stringent controls on nitrogen oxides and other toxic and volatile gases, the major ingredients of ozone recipe,” said Anumita Roychowdhury, head of CSE’s air pollution programme.
The ozone level shot up by 87% in Civil Lines, 171% in Punjabi Bagh, 315% at Mandir Marg and 82% at IGI airport, within a week, shows the study. The average ozone level at all locations was 73 microgramme per cubic metre on June 1, that quickly doubled beyond the standards by June 5.
“A person with chronic respiratory problems and bronchitis is prone to more attacks when he or she is exposed to high level of pollution. The person will have breathing difficulties and cough when exposed to the heat. One should avoid places with high levels of pollution like crossings and terminals,” said Dr Randeeep Guleria, who heads the department of pulmonary medicine at All India Institute of Medical Sciences (AIIMS).
“It is advisable for them to stay indoors and drink lot of fluids and electrolytes and wear loose clothes.
People suffering from chronic respiratory problems should increase their medication and a consult doctor. Elderly people should be very careful and always carry an umbrella when stepping out,” he added.
There are around 8 million registered vehicles in Delhi out of which 3 or 4 million are on the city’s streets daily. “Increase in vehicle numbers, especially diesel-powered ones that spew much higher levels of nitrogen oxide and volatile organic compounds, can only lead to increased ozone levels combined with the heat,” said Roychowdhury.
The study also shows that frequency of days violating ozone standards has increased with the onset of summer.
For instance, in RK Puram, while 22.5% of the days in January and 39.2% days in February have exceeded the standards, as much as 87% of days in March, 80% in April and 64.5% in May have exceeded prescribed safety limits.
Experts in CSE feel the government should reduce numbers of vehicles, especially diesel vehicles.
Diesel cars emit three times more nitrous oxides than petrol cars; nitrous oxide is the main catalyst that triggers reaction among gases to form ozone.