Because the cedar trees that were planted in large numbers after the war have grown

From during the war through the postwar period, fast-growing Japanese cedar (sugi) and cypress (hinoki) were extensively planted across Japan as building materials for the country’s reconstruction. Japanese cedar begins releasing pollen about 30 years after being planted, but as inexpensive imported lumber became widespread, Japan’s forestry industry declined, and more trees were left unharvested. As a result, these cedars grew large and began dispersing vast amounts of pollen, and it is said that the number of people developing hay fever rose sharply from the 1970s to the 1980s.

tomato

People with Japanese cedar (sugi) pollen allergies may develop oral allergy syndrome when they eat tomatoes, experiencing tingling or itching in the mouth or on the lips. This happens because the allergen in cedar pollen and the proteins in tomatoes have very similar structures, causing the body to mistake one for the other and trigger an allergic reaction. It is said that symptoms are especially likely to occur with raw tomatoes.

Japan only

It’s often said that Japan is the only country in the world where cedar pollen allergies have become a nationwide illness and a major social issue. From the postwar reconstruction period through the era of rapid economic growth, vast numbers of Japanese cedars were planted across the country as building materials for housing and other uses. However, as inexpensive imported lumber became widespread, domestic cedar was increasingly left unharvested and unmanaged. As a result, these cedars grew large and began releasing massive amounts of pollen in early spring. While ragweed and grasses are common causes of hay fever overseas, the extent to which people suffer from cedar pollen allergies in Japan is a distinctive phenomenon born of the country’s history and environment.

Okinawa

Due to its climate, Okinawa Prefecture has very few naturally growing trees like Japanese cedar (sugi) and cypress (hinoki), which are major causes of hay fever. As a result, compared to Honshu and other regions, the amount of cedar pollen in the air is extremely low, and it is known as an area with relatively few people suffering from cedar pollen allergies.

Close your eyes

If you blink repeatedly after applying eye drops, the active ingredients will flow into the back of your nose along with tears, preventing the medication from working effectively. The correct method is to gently close your eyes after instilling the drops and lightly press the inner corners. This helps the medication stay on the surface of the eye and work effectively against the itching and redness caused by hay fever.

more than 600 meters

The correct answer is over 600 meters. Because cedar and cypress pollen is extremely small and light, it rides the wind and rises high into the air. Research has shown that it can reach from an altitude of 600 meters to over 1,000 meters.

About 1 to 2 weeks before pollen starts to spread

To help keep hay fever symptoms mild, starting early countermeasures known as “initial therapy” is highly effective. Specifically, it’s recommended to begin taking medication about 1–2 weeks before pollen starts dispersing in earnest, or as soon as you notice even slight nasal irritation. If you wait until symptoms become severe, the medication may be less effective, so it’s important to stay a step ahead.