Pollution shift: Air quality dashboard shows rise in Ozone as NO2, CO decline, Pg4

Key Highlights:

• A new air quality dashboard reveals a shift in Delhi's pollution, with declining Nitrogen Dioxide (NO2) and Carbon Monoxide (CO) but rising Ozone (O3) levels.
• Delhi's annual average Ozone levels increased from 52 µg/m³ in 2021 to 66 µg/m³ in 2025, with a significant rise in Ozone-dominant days.

Detailed Insights:

• The air quality dashboard, launched by Envirocatalysts, allows for pollutant-wise, long-term analysis of emissions across cities since 2015.
• Ozone peaks during summer, especially in May, due to photochemical reactions between Nitrogen Oxides and Volatile Organic Compounds driven by strong sunlight.
• Cities like Meerut, Noida, and Muzaffarnagar have experienced the steepest increases in Ozone levels, indicating a broader regional trend.
• Despite the decline in PM2.5 and PM10 levels in Delhi, they still remain significantly above national and global safety limits.
• The persistence of PM10 pollution highlights the growing impact of dust from construction, road surfaces, and open land in the NCR.
• Delhi's Air Quality Index (AQI) is closely linked to the wider NCR, with high particulate levels in cities like Ghaziabad and Gurgaon affecting overall air quality.

Key Concepts Involved:

• PM2.5: Fine particulate matter with a diameter of 2.5 micrometers or less, posing significant health risks.
• PM10: Coarse particulate matter with a diameter of 10 micrometers or less, contributing to respiratory issues.
• Ozone: A gas formed by photochemical reactions, acting as a pollutant at ground level and a protective layer in the upper atmosphere.