A study on vertical profiling of air pollutants and meteorological variables in Visakhapatnam, an Indian coastal urban environment

Air pollution in coastal urban environments is a complex interplay of emission sources and meteorological conditions, often inadequately captured by traditional horizontal monitoring. This study investigates the vertical distribution of major air pollutants PM2.5, PM10, SO₂, NO2, NO and CO across five high-rise multi-storey buildings in Rushikonda, Visakhapatnam, during summer and winter seasons. Over 30 days of continuous monitoring with a distinct vertical gradient, where noticeable variations were observed, particularly for particulate matter, with PM2.5 and PM10 concentrations decreasing by up to 10.2% and 15.4%, respectively, from ground to elevated levels. However, statistical data analysis and 3-D visualization of the relationship between the pollutants and the meteorological parameters revealed critical thresholds for temperature, relative humidity (RH), and height influencing pollutant stratification. 3D surface visualizations further emphasized RH's role in enhancing particulate concentrations via hygroscopic growth and suppressing vertical dispersion, besides the long-range transport of air mass could also contribute to the high concentration values of particulate matter. The findings highlight the utility of vertical monitoring using existing urban infrastructure and underscore its relevance in refining air quality management in coastal cities.