Differential Quercus spp. pollen-particulate matter interaction is dependent on geographical areas

Area of Science:

• Environmental Science
• Analytical Chemistry
• Allergy Research

Background:

• Particulate matter (PM) and pollen interactions are crucial for understanding allergic reactions.
• The physical and chemical properties of PM may intensify allergic responses.

Purpose of the Study:

• To investigate the physical-chemical properties of PM adhering to Quercus spp. pollen.
• To compare PM adherence across three Portuguese cities with varying environmental conditions.

Main Methods:

• Utilized Hirst-type volumetric samplers for pollen collection.
• Analyzed adhered particles on pollen grains using Field Emission Electron Probe Microanalyser and Energy Dispersive X-ray Spectroscopy (EDS).
• Assessed air mass trajectories with the HYSPLIT model.

Main Results:

• Observed 7683 particles on 484 pollen grains; most particles were < 3 μm.
• Significant differences in particle load and area occupied per pollen grain were found between cities.
• Si-rich particles were dominant; chemical compositions varied, with Ca/SO-rich in Évora/Guarda and Organic/Cl-rich in Porto. Metals&Oxides were highest in Porto; P-rich and sea salt particles were unique to Évora.

Conclusions:

• PM physical characteristics were similar across cities, but dominant chemical compositions differed.
• Variations in PM chemical composition likely impact exposome influence and pollen-allergy intensification.