Correlation of high pollen concentrations with air pollutants and meteorological parameters: "the case of Islamabad,...

Air pollution influences climate change and contributes to respiratory allergies, yet interactions between these factors are less understood. The escalation of air pollutants and temperature increases can influence pollen concentrations, shifts in pollen seasons, and an increase in seasonal allergies. This study investigates trends of Broussonetia papyrifera, Pinus, Cannabis sativa, and grasses (Poaceae) pollen in Pakistan over the past 16 years, as well as their correlations with air pollutants and meteorological parameters. Minute-based data of 10 air pollutants were recorded using a HAZ-6000 scanner in Islamabad during 2022-23. Datasets on meteorological parameters (such as precipitation, temperature, wind speed, and relative humidity) and pollen concentrations (2008-2023) were retrieved from the Pakistan Meteorological Department (PMD). Both datasets were normalized, and monthly averages were calculated. Spearman correlation of pollen concentrations with air pollutants and meteorological factors was performed. Mean monthly pollen concentrations, meteorological parameters, and air pollutants were plotted utilizing the NCAR Command Language (NCL). Interestingly, O₃, CO₂, and NO₂ showed a positive correlation, whereas SO₂, NO, and CO showed a negative correlation with daily pollen concentrations/m³. Pollen season trends comparative analysis indicated a shift in seasonal pollen integral (SPIn), start date, and duration. This is the first study from Pakistan to suggest that increasing temperature and air pollutants correlate with higher pollen concentrations and extended pollen season. This research provides a baseline system for examining allergenic pollen season shifts over time, indicating an increase in pollen allergy abundance with climate change in South Asia.