Tokyo Dust: The Geography of Pollen

TOKYO – The weather here is turning warmer, the cherry trees are blossoming and the waiting rooms in clinics that specialize in nose and eye problems are filling up with people suffering from runny noses, sneezing and bloodshot eyes.

Tokyo is known for many things: the Imperial Palace gardens, cherry trees in the springtime, super-crowded commuter trains. But it has a more dubious distinction. It is also the world capital for allergies, especially for hay fever, known to the Japanese as pollen sickness.

Of course this is no secret to the bulk of the people living here, especially the estimated six or seven million who are prone to pollen allergies (based on general rule that 15- 20 percent of the Japanese population suffers from hay fever).

Tokyoites know that by the time the plum trees start to blossom in March, it's time to stock up on antihistamine tablets, eye drops, herbal medicines and face masks. Those most susceptible to pollen sometimes also avail themselves of allergy shots and other more exotic remedies.

One might wonder, why Tokyo? The answer goes back to just before World War II, and just after its end. In those hardscrabble years, people denuded the forests of the nearby mountains to repair burned out homes, keep warm and cook food.

In the 1950s and 1960s the Japanese government undertook a successful reforestation program, planting millions of cedars, a cheap, fast-growing native tree and a prodigious pollen producer. Unlike the US, where ragweed is the main pollen source, most of Japan's suffering is caused by cedar and cypress trees.

It was expected that these trees would be cut to produce timber, but Japan has found it more economical to import lumber from the US and Canada, so they have been left standing. Now 40 to 50 years old, they have reached their pollen producing peak, pumping literally tons of the irritant into the atmosphere.

The cedar pollen season peaks in March, but just as it dies down the pollination of the cypress trees begins to kick in. So for those who suffer from both pollens, there is an unbroken period of sneezing and sniffling through the end of April.

Ironically, it is Tokyo’s urban nature that compounds the problem, since the pollen particles fall on asphalt pavements or on the roofs of buildings rather than being absorbed in the soil. From there, they are picked up and blown around in little invisible eddies and whirlwinds.

The inexorable march of suburbia to the west has eliminated many of the farms and windbreaks that had once helped keep much of the pollen from reaching the city. But now the urban area of Tokyo extends to the very foothills of the mountains.

The forest agency, which had planted 4.5 million hectares (11.1 million acres) of cedar trees, now proposes to cut them down and reseed the areas with different broadleaf trees that produce less pollen. The goal is to halve the number of cedar trees by 2017.

Hay fever is thought to have a measurable impact on Japan’s economy, both in a negative and a positive way. The Dai-Ichi Life Insurance Research Institute estimates that the economy lost about $3 billion due to absenteeism in the memorable hay fever year of 2005. On the other hand, Dai-Ichi Life also estimates that Japanese spend more than $6 billion a year on hay fever prevention products, such as eye drops and face masks.

Dust that originates in China’s Inner Mongolia province and other parts of Central Asia and is blown east in prevailing winds is called "yellow dust" by the Japanese. In recent years, the hay fever season has merged with the yellow dust peril to aggravate the woes of allergy sufferers.

When it settles, cities are bathed in a kind of yellow haze, similar to smog, and the dust particles get into everything. Weather reports on local television stations plot the approaching dust and recommend that people refrain from hanging washed clothing out of doors. In more extreme cases, the yellow dust can cut visibility to the point where airports close temporarily.

Of late, the yellow dust has been augmented by real smog from China. In Fukuoka city on Kyushu, the average amount of particulates is estimated to have reached 50 micrograms per cubic meter. The air pollution from China has caused the first official smog alerts in Japan.

This being Japan, various exotic remedies have been proposed over the years to lessen the burden. One pharmaceutical company touts its olive leaf extraction as a way of alleviating hay fever symptoms without causing side effects such as drowsiness.

An institute associated with the Ministry of Agriculture, Forestry and Fisheries touts a new kind of genetically engineered rice. Eating it may produce an immune tolerance. The rice is said to produce an amino acid that mimics the cedar pollen and helps produce immunities.

However, the Health, Labor and Welfare Ministry has been slow to classify the engineered rice as a safe food, disappointing many sufferers who had hoped it would be available from this year’s harvest.

Several Japanese companies are increasing the production of face masks for sale in Japan. One firm, Ohyama, has developed an improved mask to screen out micro particles. The masks are made in Dailin China.

At this time of year newspapers carry stories filled with tips on how to prevent, or at least alleviate, the symptoms of hay fever. They all seem to boil down to the same piece of advice: find and wear a good face mask or stay indoors.

Todd Crowell is a writer based in Tokyo.

Flickr photo by OiMax: Yellow Dust , Tokyo, Japan