Large increase in anthropogenic emissions in an urban environment and their associated air quality implications

Anthropogenic aerosols play a crucial role in contributing to visibility reduction, degrading air quality, altering the hydrological cycle, and perturbing the Earth's atmospheric energy balance. This study investigates the anthropogenic particulate matter emissions and their associated impacts on air quality, with a particular emphasis on the rising problem of smog formation in Peshawar, Pakistan. Therefore, for the first time, this study assesses US Consulate NowCast data on fine particulate matter (PM2.5) with ozone monitoring instrument (OMI) data on trace gases over the period from 1 January 2020 to 31 December 2024. It was observed that the daily and annual PM2.5 concentrations of 90 and 99 µg/m3, respectively, surpass the permissible National Environmental Quality Standards (NEQS) and World Health Organization (WHO) air quality guidelines. The daily concentrations of PM2.5 were found to exceed threefold NEQS and sixfold WHO limits, while the annual amount was 7 times NEQS and 20 times WHO. The results of Mann's Kendal (MK) test revealed a significant (p ≤ 0.05) increasing trend in daily, 30-day rolling averages, and annual concentrations of PM2.5 from 2020 to 2023. In 2024, it was found to decrease, but it was still higher in the winter season. In addition, PM2.5 showed a moderate to strong correlation with key trace gases, including nitrogen dioxide, ozone, and sulfur dioxide. Likewise, PM2.5 concentrations were evaluated using the air quality index, and the study area was classified as 51% unhealthy and 26% unhealthy for sensitive groups. This study concludes that the air quality of Peshawar is worsening, with PM2.5 levels consistently surpassing air quality guidelines, highlighting the need for immediate and sustainable strategies to combat smog pollution in the region.