Patterns and Seasonal Changes of Airborne Pollens in Phitsanulok, Lower Northern Thailand: A 16-Year Aeroallergen Survey
Suwannee Uthaisangsook¹, Boonchua Dhorranintra², Sirirat Bunarsa³
Affiliation : ¹ Department of Pediatrics, Faculty of Medicine, Naresuan University, Phitsanulok, Thailand; ² Department of Pharmacology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand; ³ Fundamental Medical Research Unit, Faculty of Medicine, Naresuan University, Phitsanulok, Thailand
Objective: Airborne pollens are significant triggers of allergic rhinitis, atopic conjunctivitis, and asthma. The present study aimed to examine the patterns, quantities, and dynamic changes of airborne pollens in Phitsanulok, lower northern Thailand, during three periods, November 2006 to October 2007, August 2013 to July 2014, and August 2022 to July 2023.
Materials and Methods: In 2006 to 2007, airborne pollens were collected using a Rotorod sampler positioned 1.5 to 2 meters above ground. In 2013 to 2014 and 2022 to 2023, pollens were collected using a Burkard seven-day volumetric spore trap positioned 15 meters above ground. The exposed rods and slides were stained for microscopic analysis. Meteorological data were also obtained.
Results: Monthly airborne pollen counts ranged from 48 to 304 grains/m³ in 2006 to 2007, 28.1 to 110.8 grains/m³ in 2013 to 2014, and 60.7 to 151.7 grains/m³ in 2022 to 2023. Peaks occurred in February, May, and August in 2006 to 2007, December in 2013 to 2014, and February and December in 2022 to 2023. Wild grass and cultivated grass were the most and second most common pollen, respectively, across all three periods, with variations in the pollen types ranked third to tenth. Total annual rainfall from 2013 to 2014 was the lowest among the three periods. The highest temperatures and lowest humidity levels, recorded in April 2013 to 2014 and 2022 to 2023, corresponded to low pollen levels.
Conclusion: The average monthly pollen count during 2022 to 2023 was lower than that recorded in 2006 to 2007 but slightly higher than in 2013 to 2014. Wild grass was the predominant pollen type over the 16-year period, with levels considered a high allergic risk.
Received 2 February 2025 | Revised 25 April 2025 | Accepted 28 April 2025
DOI: 10.35755/jmedassocthai.2025.6.490-499-02873
Keywords : Airborne pollens; Grass pollens; Pollen counts; Allergic symptoms; Asthma; Thailand
