Regional and seasonal variation of airborne pollen and spores among the cities of South China

The composition and relative abundance of airborne pollen in urban areas of south China are strongly influencedby geographical location, vegetation, climate, and sampling device. This paper summarizes the latest reports onair pollen for 12 major cities in southern China from 1986 to 2017. The most significant taxa across all sites arePinaceae, Poaceae, Cupressaceae, andPlatanus, making up over 50% of the total airborne pollen in urban environ-ments throughout the years. Clear shifting has been observed from long pollen seasons in the tropics to shorterperiods in the south middle and north subtropical regions. There is also a discernible shift in the initiation andlength of the pollen season towards higher latitudes. Both reflect the strong influence of solar radiation incidenceon pollen production during spring and summer months in the southern urban areas. In this study, the compar-ison between airborne pollen and meteorological data indicates that the airborne pollen concentration was pos-itively related to temperature but negatively related to precipitation and relative humidity. This study revealsthat the consistent wind speed over the year had a very little but positive effect on pollen and spore concentra-tion. The active sampler (volumetric method) in Guangzhou and Zhanjiang collected more spore and pollen spe-cies than the passive sampler (gravity method) in other cities. Understanding the future potential impacts ofclimate change on the phenological cycles and range of allergenic species is a critical step in the advancementof aerobiology studies in south China.