Pollen allergies have hit more and more Japanese over the last 30 years. Pollen from cedar trees has created conditions unique to Japan. Vast amounts of the pollen drifts over wide areas every year, from the last part of February to the first part of May, and during that time you're likely to see people wearing masks wherever you go. Cedar pollen allergies have become an unfortunate trend.

I spoke with Dr. Okuda Minoru, an allergy specialist. "Cedar pollen allergies (hay fever) have become a national phenomenon in Japan. The number of sufferers has grown dramatically since the 1970s. Experts say that 12-13% of the population, about 15 million people, now experience symptoms during the pollen season." Dr. Okuda is Chairman of the Japan Allergy Foundation, and an honorary professor at Nippon Medical School.

Pollen enters the nose or eyes, then can trigger an allergic reaction—itching, a runny or clogged nose, and watering eyes. The symptoms might last a long time, interfering with sleep and making it difficult for the mind to concentrate. Work and studies suffer greatly as a consequence.

A complete cure is difficult, but the symptoms can be reduced through proper medical treatment from a specialist. Pollen allergies are a relatively new ailment, so there aren't many doctors with extensive experience in treating them. The allergy is not life threatening, and people don't want to go to a crowded hospital for relief. They tend to go to a pharmacy instead, for a medication that can be partially effective. A surprising number of people wear a mask or even goggles to try to ward off the pollen.

The most devilish aspect of the allergy is that it strikes all of a sudden. Dr. Okuda says, "We assume that air pollution, as well as changes in lifestyles and eating habits, are to blame for the increase in this type of allergy, yet we still don't know for sure. But one thing that is certain is that the number of patients has been increasing in proportion to the rise in the amount of windborne cedar pollen."

From around 1949 to 1970, huge numbers of Japanese cedar trees were planted in many parts of the country. Wood was in great demand for new housing, because many people had lost their homes to fire during World War II, and because of the post-war rise in the number of nuclear families and demand for housing in growing cities. The market focused on Japanese cedar trees because they grow fast. Planted cedar forests now cover 12% of Japan's total land area—that's more than 45,000 km². The trees start producing pollen when they are about 30 or 40 years old, so the increase in windborne pollen volumes just about coincides with the increase in the number of pollen allergy sufferers.

Pollen counts are high from February through to April, around the time of school entrance exams, graduation, job openings, and the busy accounting period at the end of the fiscal year. It is also the cherry blossom season, a favorite time for many. But for cedar pollen sufferers, it's the most miserable time of the year.