Hay fever season has arrived in Japan, presenting sufferers with an added challenge amid the coronavirus pandemic as rubbing itchy eyes and wiping runny noses threaten to boost the risk of viral infection, while opening doors and windows to improve ventilation could add to the amount of pollen coming indoors.

As of Sunday, the cedar pollen season — triggered by a rise in temperatures — had started in 34 of the nation's 47 prefectures stretching from the Kyushu region in the southwest to the Tokyo metropolitan area, according to Weathernews Inc.

The allergy-causing pollen is expected to begin dispersing in the Tohoku region in the northeast as well as the Hokuriku area in central Japan later this month, it said.