Airborne pollens in Wuhan urban area and its correlation with hospital visits of allergic rhinitis patients from 2017 to 2018

Abstract

Objective: To investigate the species and concentrations of airborne pollens in Wuhan urban area and their correlation with the number of visits of allergic rhinitis patients. Methods: Retrospective analysis of pollen dispersal characteristics and the number of patients with allergic rhinitis presenting to Tongji Hospital of Huazhong University of Science and Technology in Wuhan city from October 2017 to September 2018, as well as pollen allergen testing results of patients with allergic rhinitis presenting to the Department of Allergy during the same period. Pollen data was collected by a 1-year air sampling conducted in Wuhan City during the same period using the volumetric method. The samples were examined microscopically to identify airborne pollen species and counted, and the concentrations of various pollens were calculated. Information on patients with allergic rhinitis who came to the hospital during the same period was collected, and the correlation between pollen concentration and the number of patient visits was statistically analyzed using Pearson correlation analysis. Results: A total of 35 types of airborne pollen were collected from October 2017 to September 2018. The dominant pollens in spring were Moraceae (68.46%, 1 042/1 522), Pendula (12.22%, 186/1 522) and Cupressaceae (2.30%, 35/1 522); in summer and autumn, the dominant pollens were Artemisia (3.81%, 58/1 522), Humulus (4.01%, 61/1 522) and Ambrosia (0.59%, 9/1 522). The peak number of visits for allergic rhinitis patients occurred in March-April and July-September, both exceeding 2 200 visits and reaching a maximum of 2 545 visits. There was a very weak correlation between the number of visits and the total pollen concentration (r=0.17, P=0.001). The average monthly pollen skin prick test positive rate of patients with allergic rhinitis was highest in March-May, exceeding 40% with a maximum of 45.73%, and there was a significant correlation between the positive pollen skin prick test positive rate and the average monthly pollen concentration (r=0.62, P=0.031). Conclusions: Pollen species and concentrations fluctuated continuously with time in Wuhan urban area, with peak pollen dispersal in spring from March to April and in autumn from August to September. The number of visits to patients with allergic rhinitis and the positive pollen skin prick test positive rate increased accordingly during the peak pollen concentration periods.