Seasonal dispersion and trajectory-based source assessment of particulate air pollutants: an integrated monitoring and HYSPLIT modeling approach

The temporal variation of air pollutants and their dispersion patterns in Dattawadi, Nagpur, India, based on twice a week air quality monitoring with 104 measurements over the study period, with HYSPLIT, a trajectories and backward dispersion modeling. sulfur dioxide (SO₂) and nitrogen dioxide (NO₂) were consistently at lower levels compared to their national standards, with median values being 7 µg/m 3 and 23 µg/m 3 , respectively. Particulate matter (PM 10 , PM 2.5 , and TSPM), on the contrary, reached critical levels and consistently exceeded the maximum acceptable limits. The average PM 10 was 90 µg/m 3 and often surpassed the 100 µg/m 3 , with 46 occurrences exceeding that level and reaching a daily maximum of 180 µg/m 3 . PM 2.5 averaged at 62 µg/m 3 , which is above its 60 µg/m 3 standard, with 45 days having daily average excesses and high values up to 127 µg/m 3 . The TSPM levels also regularly exceeded 159 µg/m3 and even climbed to 250 µg/m 3 . The seasonal study indicated that meteorological conditions varied in their effect on pollutant dispersion, long-distance transportation of pollutants originating in the North-Northeast, which resulted in significant accumulation of pollutants and high deposition possibilities (up to 5.4 × 10 –10 mg/m 2 in post-monsoon). Summer displayed stronger winds and contributed to increased vertical mixing, whereas the monsoon season was more favorable due to wet deposition by the southwesterly and westerly winds, leading to cleaner air. These results highlight the need for a season and problem focused approach to air quality management to minimize particulate pollution and protect the health of the population.