DECIPHERING URBAN AIR QUALITY THROUGH MULTI-POLLUTANT ASSESSMENT

Abstract

The increasing urbanisation, traffic, industrial activities, construction and energy usage has further exacerbated air quality issues in urban areas of India. The study adopted a quantitative, observational and longitudinal approach to assess the multi-pollutant pattern in Delhi, Mumbai, Kolkata, Chennai and Bengaluru from 2015 to 2024. The concentrations of PM₂.₅, PM₁₀, NO₂, SO₂, CO and ground-level O3 were analysed in conjunction with Air Quality Index categories. Spatial and temporal variations were interpreted using descriptive statistics, city-wise comparison, annual and seasonal assessment, correlation analysis and principal component analysis. The findings showed that PM being the most predominant pollution concern in the urban environment, the pollution burden in Delhi was the highest, while the levels of particulate matter were comparatively lower in the cities of Chennai and Bengaluru. Strong association with PM₁₀ and moderate correlation with NO₂ and CO indicated the common effect of traffic and other sources of combustion, dust, and construction activities on PM₂.₅. The particulate accumulation was the highest in winter and post-monsoon season while monsoon had lowest particulates. Overall, there was a decreasing trend in annual AQI values; however, in certain cities improvement was uneven, and unhealthy conditions were observed for significant periods of the assessment period. To achieve this, comprehensive traffic and road and construction dust, industrial combustion, municipal waste burning, household fuel consumption emission control is required. The multi-pollutant assessment provides a better foundation for air-quality management, exposure reduction, public-health protection and long-term urban environmental planning on a city-by-city basis.