Assessment of seasonal and annual allergenic type of pollen in North Lebanon between 2008 and 2012 and their relationship to drought conditions

Abstract

Of all the factors that cause allergy, pollen is the most common one, and unlike allergenic food or even allergenic insects, which can be avoided, pollen allergy is very difficult to avoid. Identification of the type and concentration of pollen will help patients lower the risk of catching certain types of allergies. Pollen allergy differs from other kinds of allergies because it occurs in a specific season of the year that varies according to prevailing climatic conditions. In this context, the aim of this work was to advance the assessment of seasonal and annual allergenic types of pollen in North Lebanon. The specific objectives were to 1) assess seasonal and annual disparity of common allergic types of pollen in North Lebanon between 2008 and 2012, 2) characterize the surface features of pollen grains of the top 10 common allergenic pollen, 3) evaluate the correlation of the concentration of common allergenic pollen during their main pollination season with current drought conditions, and 4) evaluate the concentration of common allergenic pollen during future drought conditions (2020). Samples of airborne pollen in North Lebanon were collected from 2008 until 2012. The identification methodology was based on the identification key for the pollen content of the air done by the French "Réseau National de Surveillance Aerobiologique". The main pollination season (MPS) of each of the top 10 was calculated to evaluate the correlation of the concentration of common allergenic pollen during their main pollination season with current and future drought conditions using the Keetch-Byram Drought Index (KBDI). As a result, the annual disparity of common allergic type of pollen in north Lebanon from 2008 until 2012 varied from one year to another for the same species as well as between different species. Some had early beginning of main pollination season; others took much more time to begin. Allergic pollens differed in their shape and size and the different morphological characteristics of the identified allergenic pollen grains were documented. More precisely, it was observed that the top allergenic pollens had negative correlation with KBDI during MPS in the period extending from 2008 to 2012 in 2020, a temporal variation in the MPS was observed for all of the top 10 allergenic pollen.