Japan's Environment Ministry warns that a massive amount of cedar pollen, an allergen that causes sneezing and running noses, is expected to be in the air this season in many parts of the country.

In order to estimate the amount of pollen that will be dispersed, the ministry counts the number of male flower buds on cedar trees in 34 prefectures.

The ministry found that this season the number of buds exceeds the average for the past 10 years in 23 prefectures from southern Tohoku to Kyushu.

The bud-counts were the highest in a decade in 12 prefectures: Fukushima, Tokyo, Kanagawa, Niigata, Toyama, Ishikawa, Kyoto, Hyogo, Okayama, Tottori, Hiroshima and Fukuoka.

The counts for Tottori, Toyama and Okayama were more than double the average, and almost double in some other prefectures.

The ministry says the areas with greater-than-average numbers of male buds had longer daylight hours and higher temperatures last summer.

The ministry says such measures as placing a gauze pad inside a face mask, drying laundry indoors and frequently mopping floors can be effective.