A growing number of people worldwide are contracting allergic diseases caused by pollens. 

The seasonal variations in pollens have occurred everywhere and the sensitization rate to pollens has increased in children as well as in adults. 

Moreover, allergenic plants, such as ragweed and Japanese hop, grow in soil damaged by human’s activities and deforestation with air pollution. It is impossible to avoid plants that cause allergies, because pollens can travel many kilometers in the breeze or wind. 

Hence, it is essential to survey and forecast pollens for the management of pollen allergy. 

Weather conditions may alter pollen concentrations.

A number of studies have shown that increases in CO2 concentration and atmospheric temperature raise pollen concentration. 

Hence most of the studies on the impact of climate change on aeroallergens must include the amount and allergenicity of pollens.

It is yet unknown whether complex interactions with pollens, meteorological variables, and air pollutants in the changing environment. 

Considering the effect of climate change on the long-term trends in pollen levels and emerging viral infection, it is crucial to forecast and eliminate the associated risk for human health in future and take appropriate measures to reduce it.