Exposure to ragweed pollen and Amb a 1 allergens in central Anatolia, Türkiye, and immunolabeling of Amb a 1 in pollen

Ambrosia artemisiifolia L., or short ragweed, is an invasive species known for its highly allergenic pollen and impact on agriculture. Native to North America, it has spread to northern Türkiye, with models suggesting pollen influx through the Black Sea region. This study had several objectives: (1) to investigate the dynamics and origin of Ambrosia pollen and Amb a 1 allergen emissions in Ankara, a Central Anatolian city with 6 million residents; (2) to examine the effects of meteorological factors on pollen and allergen emissions; (3) to determine the duration of possible risky days for Ambrosia allergy; and (4) to determine the localization of Amb a 1 allergens within the pollen structure using immunolabeling with transmission electron microscopy (TEM). Daily pollen concentrations were obtained using a Burkard spore trap, and Amb a 1 allergen concentrations were measured using a BGI900 high-volume air sampler. Filters capturing PM_>10 and PM_10>2.5 fractions were analyzed via sandwich ELISA. Seasonal Ambrosia pollen indices were 189 in 2015 and 21 in 2016, with allergen concentrations peaking on August 29, 2015 (1620 pg/m³) and August 17, 2016 (201 pg/m³), primarily in PM_>10 fractions. Backward trajectory analysis (HYSPLIT) identified air masses from Ukraine, Crimea and Russia as probable sources, with higher pollen levels linked to northeast and east winds. This is the first study to detail Amb a 1 allergen localization in ragweed pollen. Immunolabeling localized allergens in the pollen wall (columella, cavea and intine) and ribosome-rich cytoplasmic areas, with no labeling observed in starch grains.