Impact and Correlation of Environmental Conditions on Pollen Counts in Karachi, Pakistan

A quantitative and qualitative survey of airborne pollen was performed in the city of Karachi, and the pollen counts were correlated with different climatic conditions. The aim of the study was to determine the possible effect of meteorological factors on airborne pollen distribution in the atmosphere of Karachi city.Pollen sampling was carried out by using Burkard spore Trap for the period of August 2009 to July 2010, and a total of 2,922 pollen grains/m3 were recorded.In this survey, 22 pollen types were recognized. The highest pollen count was contributed by Poaceae pollen type (1,242 pollen grains/m3) followed by Amaranthaceae/Chenopodiaceae (948 pollen grains/m3), Cyperus rotundus (195 pollen grains/m3) and Prosopis juliflora (169 pollen grains/m3). Peak pollen season was in August showing a total of 709 pollen grains/m3 and lowest pollen count was observed in January-2010. Pearson’s chi-square test was performed for the possible correlation of pollen counts and climatic factors. The test revealed significant positive correlation of wind speed with pollen types of Amaranthaceae/Chenopodiaceae; Brassica campestris; Asteraceae; and Thuja orientalis. While the correlation of “average temperature” showed significant positive value with Asteraceae and Tamarix indica pollen types. Negative correlation was observed between humidity/ precipitation and pollen types of Brassica campestris; Daucus carota; Ephedra sp.; and Tamarix indica. In the light of above updated data one could identify various aeroallergens present in the air of Karachi city.