CSE analysis says South Delhi, New Delhi worst affected by ground-level ozone

CSE analysis says South Delhi, New Delhi worst affected by ground-level ozone

Subject :Environment

Section :Pollution

Context:

• According to a new analysis by the Centre for Science and Environment (CSE), parts of the Delhi-NCR region witnessed ground-level ozone readings exceeding the national standards on 87 out of 92 days in the summer period between March and May. The worst affected parts in the area are New Delhi and South Delhi neighbourhoods.

Details:

• The region is seeing a rare phenomenon where ozone levels remain elevated hours after sunset — ground-level ozone should ideally become negligible during the night.
• Another issue is that the pollutant, which once used to be prominent only during the summers, has become a yearlong problem.
• The pollutant can also travel long distances due to wind and affect rural areas also.

Ground-level Ozone:

• Also known as tropospheric ozone.
• It is a colourless and highly irritating gas that forms just above the Earth’s surface (up to 2 miles above the ground).
• It’s not directly emitted into the air but rather produced when two primary pollutants react in sunlight and stagnant air.
• These two primary pollutants are nitrogen oxides (NOx) and volatile organic compounds (VOCs).
• Therefore, ground-level ozone is called a “secondary” pollutant.

Sources of NOx and VOCs:

• NOx and VOCs come from natural sources as well as human activities.
  • About 95 per cent of NOx from human activity comes from the burning of coal, gasoline and oil in motor vehicles, homes, industries and power plants.
  • VOCs from human activity come mainly from gasoline combustion and marketing, upstream oil and gas production, residential wood combustion, and from the evaporation of liquid fuels and solvents.

Harmful effects of Ground-level ozone:

• The ground-level ozone is a highly reactive gas and it has serious health consequences.
• Those with respiratory conditions, asthma, chronic obstructive pulmonary disease, and particularly children with premature lungs and older adults are at serious risk.
• This can inflame and damage airways, make lungs susceptible to infection, aggravate asthma, emphysema, and chronic bronchitis and increase the frequency of asthma attacks leading to increased hospitalisation.
• The pollutant can also affect sensitive vegetation and ecosystems, including forests, parks and wildlife refuges.
• Significantly, it can harm sensitive vegetation during the growing season too.

Situation of Ground-level Ozone in India:

• As per the 2020 State of Global Air report, the age-standardised rates of death attributable to ground-level ozone are among the highest in the country.
• The seasonal 8-hour daily maximum concentrations have recorded one of the highest increases in India between 2010 and 2017– about 17 per cent.

Gothenburg Protocol 1999 (Multi Effect Protocol):

• The official title of the protocol is UNECE Protocol to Abate Acidification, Eutrophication, and Ground-level Ozone (Gothenburg Protocol) (Protocol to the UNECE Convention on Long-Range Transboundary Air Pollution (LRTAP)).
• The Gothenburg Protocol was established to address pollutants that cause acidification and ground-level ozone.
• It sets limits on air pollutants including sulfur dioxide, nitrogen oxide, ammonia, and volatile organic compounds that are hazardous to human health and the environment.
• It was updated in 2012 to include particulate matter (PM) and black carbon (as a component of PM) and to include new commitments for 2020.
• The Protocol establishes legally binding emissions reduction commitments for 2020and beyond for the major air pollutants:
  • sulfur dioxide (SO2), nitrogen oxides (NOx), ammonia (NH3), volatile organic compounds (VOCs), and delicate Particulate Matter (PM5).
  • these chemicals also contribute to photochemical smog formation.