Visible evidence that the air is cleaner in Tokyo today than years past is that Tokyo Tower can be glimpsed most days of the year from a meteorological observatory located some 17 kilometers in the distance.
The 333-meter landmark structure was visible from the Kichijoji district, in the west of the capital, on 328 days last year, which is practically year-round except on days of foul weather, records of a private observatory show.
The number is up eightfold from only 41 days when monitoring started 62 years ago, likely because the air is cleaner due to pollution control measures.
The yearly count has risen remarkably since 2000, as regulations were tightened on exhaust emissions from diesel vehicles.
The records were compiled by Seikei Meteorological Observatory on the campus of the Seikei Gakuen private school complex in Musashino, western Tokyo. The Seikei observatory will celebrate the centenary of the start of its measurements next January.
Monitoring of the visibility of Tokyo Tower located in Minato Ward from the observatory began on Jan. 1, 1963.
Officials in charge inspect the visibility from the rooftop of a schoolhouse of Seikei Junior and Senior High School at 9 a.m. every day.
Not a single day has been missed since the monitoring started, officials said.
VISIBLE ON MORE CLOUDY, RAINY DAYS
The observation data shows that Tokyo Tower was visible from the schoolhouse on a record 329 days in 2023.
The count has consistently been on an upward trend since it hit bottom at only 29 days in 1969.
Previously, Tokyo Tower was not always visible even on clear days, but the structure has come to be seen on more rainy and cloudy days since 2000, the officials said.
“That is because advancements in pollution control measures have made the air cleaner,” said Takehiko Mikami, a Tokyo Metropolitan University professor emeritus of climatology, who is Seikei observatory director. “Considering that conditions are unfavorable on certain days, including due to foul weather, you could say that Tokyo Tower is now practically visible year-round.”
Pollution became a serious concern during the high economic growth period of the 1960s and the early 1970s.
The central government therefore began tightening its regulations on exhaust emissions from plants and vehicles in the second half of the 1960s. The Tokyo authorities introduced particularly stringent regulations on diesel vehicles in 2003.
The rise in the number of days that Tokyo Tower is visible is correlated with the effects of those environmental control measures, Mikami said.
MOUNT FUJI ALSO VISIBLE 7 TIMES MORE OFTEN
Seikei observatory has also been monitoring the visibility of Mount Fuji situated 83 km to the west-southwest.
Japan’s highest peak was visible on 153 days last year, seven times the least record of only 22 days in 1965.
The gently rising trend is proof that the air in Mount Fuji’s direction is also becoming cleaner, Mikami added.
Seikei observatory plans to continue with the visibility observations into the future.
“Continuity matters in weather observations,” Mikami said.
But he said there are new concerns for the years to come.
“Skyscrapers that will go up in the midtown area could conceal the very Tokyo Tower behind them,” he said.
AloJapan.com