Pollen is released by different trees and plants throughout the year. In the Kanto region, for example, cedar trees are active from February through April, while Japanese cypress trees primarily release pollen in April and May. In June, pollen is released by orchardgrass, followed by mugwort and ragweed during autumn.
Scientists believe that high temperatures during summer cause more pollen to be released the following spring. Some experts say that global warming is behind the rising number of hay fever sufferers in recent years.
In a time of both misinformation and too much information, quality journalism is more crucial than ever. By subscribing, you can help us get the story right.
With your current subscription plan you can comment on stories. However, before writing your first comment, please create a display name
in the Profile section of your subscriber account page.
Your subscription plan doesn't allow commenting. To learn more see our FAQ
With your current subscription plan you can comment on stories. However, before writing your first comment, please create a display name in the Profile section of your subscriber account page.