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Japan is gripped by mass allergies. A 1950s project is to blame (bbc.com)

365 points by ranit · 102 days ago · 166 comments on HN

Article summary

Japan is experiencing a national crisis due to widespread hay fever caused by pollen from Japanese cedar and cypress trees, which were planted in large quantities after World War II to prevent soil erosion. The country is now trying to address the issue by reducing the number of these trees and replacing them with more diverse forests. The problem is exacerbated by climate change, which is causing earlier and more severe pollen seasons. The Japanese government has set a goal to reduce pollen by 50% in 30 years.

Main themes

  • Japan's hay fever crisis
  • Forestry and reforestation
  • Climate change impact
  • Allergy development and exposure
  • Environmental policy and management

What commenters say

  • Repeated exposure to allergens can cause allergic symptoms in people who were previously not allergic, as seen in the case of hay fever in Japan.
  • The development of allergies can be influenced by factors such as humidity, air conditioning, and urban vs. rural environments.
  • Some people believe that the increased use of air conditioning contributes to the development of allergies by drying out the air and irritating the nasal passages.
  • The Japanese government's decision to plant large quantities of a single tree species after World War II has been criticized as a contributing factor to the current hay fever crisis.
  • There is a debate about the effectiveness of measures such as allergy shots and medication in alleviating hay fever symptoms, with some people finding them helpful and others not.
  • The relationship between allergy development and exposure to allergens is complex, and some people may develop resistance or tolerance to certain allergens over time.
  • The distinction between natural forests and monoculture plantations is important when considering the environmental impact of forestry practices.
  • Economic factors, such as the cost of importing wood, can influence the management of local forests and the development of allergies.