The Tokyo Metropolitan Government says the cedar pollen season started on Friday in Japan's capital. The pollen causes hay fever.
Officials say the amount of cedar pollen particles exceeded the benchmark for two straight days from Friday in the cities of Tachikawa, Tama and Ome among the 12 observation locations.
The officials say the cedar pollen season arrived one day earlier than last year, and six days earlier than the average for the past 10 years.
They say cedar flowers apparently bloomed early because of higher-than-usual temperatures in January.
The officials expect this year's amount of cedar and Japanese cypress pollen in the air over Tokyo to be roughly the same as usual, and around 80 percent of last year's figure -- the second largest over the past decade.
The Tokyo government provides observation data online, and is urging people to wear masks and glasses, among other measures, when going out on days of high pollen levels.