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No.234 (4/12/13)

Asian Dust, Pollen, PM2.5 Raid on Japan

By Chiho Tsukiashi
Staff Writer

You might have wondered why so many Japanese wear surgical masks in public. Especially in spring, you see more people cover their noses and mouths on the street. Most of them are protecting themselves from inhaling pollen and from getting infected from colds and other diseases. It is also public manners to wear a mask to avoid spreading viruses if you have a cold. This year, however, another reason comes up especially in southern Japan. They are advised to wear masks to avoid breathing in PM2.5 (particulate matter 2.5 micrometers-particles smaller than 2.5 micrometers tend to penetrate into the gas exchange regions of the lung-See Wikipedia) and Asian dust, which can harm their health.

Asian Dust
Here in Misawa, you might have noticed your car windshield is slightly covered with yellow dust in spring. This dust comes all the way from the Yellow River region in China. The dust gets thicker as you go south. Damage from the Asian dust approaches $6.65 billion all over Asia each year. As it gets closer to the Yellow River in China, the haze is thicker and its impact gets more severe. The dusty haze blocks sunlight and vision, obstructs transportation, and even harms lungs of people and livestock. Because the particles of Asian dust irritate the respiratory tract, it can cause cough and worsen symptoms from hay fever, conjunctivitis, and asthma. In addition to the damage to respiratory organs, it also irritates skin causing dry skin and symptoms of atopic dermatitis. In some regions of China,sandstorms occur and they can be as powerful as tornadoes, giving rise to the phenomenon called Asian dust. Search ‘You Tube' with “sandstorm, China” as keywords, and you will find some extraordinary videos. Asian dust is brought to Japan on low atmospheric pressure systems from early spring to early summer. The movement of Asian dust was not big news until this year in Japan, however. People were only annoyed by spotting it on their cars and laundry hung up to dry outside. Now they are worried about its adverse influence on their health. The dust can be harmful because it contains PM2.5, which may cause serious illness such as lung cancer, respiratory diseases, and even damage to the heart. In some southern regions in Japan, parents and teachers do not let children play outside. Mask sales have quadrupled, and the sale of air cleaners has tripled compared to sales the previous year.

What is PM2.5?
PM2.5 means Particulate Matter 2.5 micrometers or less. They are extremely small particles floating in the air, about 1/30th the diameter of a hair. Some originate naturally, such as soil, sea water, and volcanic ash. Others come from pollutants in the atmosphere consisting of complex mixtures of oxides of sulfur and nitrogen, and volatile organic compounds. In China, air pollution has become a serious problem as a by-product of its rapid economic development. PM2.5 emitted from factories creates a thick haze which covers the sky in large cities throughout the country. The polluted air together with Asian dust attacks nearby countries including southern Japan, creating international conflicts. In March this year, atmospheric concentrations of PM2.5 temporarily exceeded the environmental standard in the Tokyo area. The Ministry of Environment predicts that high concentration of PM2.5 may continue through the end of May, depending on the amount of Asian dust and wind directions.

What you can do
What you can do to protect yourself from Asian dust, PM2.5, and pollen is to wear glasses and a facial mask outside, gently brush your clothes before you enter your home, and use air cleaners with filters meeting the HEPA standard. HEPA filters are High Efficiency Particulate Air filters. Facial masks are sold at drug stores and grocery stores in Misawa. Prices vary. In general, the more expensive masks are more effective. Most masks except the cheapest ones have a wire on the upper part to bend to fit your nose closely. The best selling air cleaner, according to, is the Uruoi Hikari Kureru TCK 70M (Daikin Co. Ltd.) at around 30,000 yen range. It also functions as a humidifier, and has a dust sensor and odor detector. When it senses dust and odor, it automatically turns on. It discharges plasma, highly ionized gas, which destroys pollen and harmful chemical substances. The filter has to be changed only once a decade.

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