Ground-Level Ozone Pollution: South Delhi, New Delhi Faces Alarming Crisis

Ground-Level Ozone Pollution: South Delhi, New Delhi Faces Alarming Crisis

Ground-level ozone pollution has been making headlines in South Delhi, New Delhi, as reported by the Centre for Science and Environment (CSE). Between March and May, parts of the Delhi-NCR region experienced ground-level ozone readings that exceeded the safe standards of 50 parts per billion (ppb) over an 8-hour average. What is particularly concerning is that the ozone levels remain elevated even at night, which is unusual as they should ideally become negligible during nighttime. This issue has become a yearlong problem in the region.

Ground-level ozone, also known as tropospheric ozone, is a colorless and highly irritating gas that forms just above the Earth's surface, up to 2 miles above the ground. It is categorized as a "secondary" pollutant because it is not directly emitted into the air. Instead, it is produced when two primary pollutants, nitrogen oxides (NOx) and volatile organic compounds (VOCs), react in the presence of sunlight and stagnant air. These primary pollutants can originate from both natural sources and human activities.

Human activities are major contributors to NOx and VOC emissions. Approximately 95% of human-generated NOx comes from burning coal, gasoline, and oil in motor vehicles, homes, industries, and power plants. VOCs primarily result from gasoline production and combustion, residential wood combustion, and the evaporation of liquid fuels and solvents.

Ground-level ozone tends to breach safety standards on hot summer days in urban areas, but it can also reach unhealthy levels during colder months. Additionally, this pollutant can travel long distances through wind patterns, affecting even rural areas.

Ground-level ozone has significant harmful effects on human health. It is a highly reactive gas that can inflame and damage airways, making lungs more susceptible to infection. People with respiratory conditions, asthma, chronic obstructive pulmonary disease (COPD), as well as children with premature lungs and older adults, are particularly at risk. Exposure to ground-level ozone can exacerbate asthma, emphysema, chronic bronchitis, and lead to increased hospitalization rates.

Not only does ground-level ozone impact human health, but it also affects sensitive vegetation and ecosystems. This includes forests, parks, and wildlife refuges. During the growing season, ground-level ozone can harm sensitive vegetation, further exacerbating environmental concerns.

In recent years, ground-level ozone has emerged as a serious public health issue in India. According to the 2020 State of Global Air report, India has witnessed one of the highest increases (17%) in seasonal 8-hour daily maximum concentrations of ground-level ozone between 2010 and 2017. Furthermore, age-standardized rates of death attributable to ground-level ozone are among the highest in the country.

Overall, the presence of ground-level ozone pollution in South Delhi, New Delhi, and its impact on human health and the environment underscores the urgent need for effective measures to mitigate and control this hazardous pollutant.

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