PM2.5

1. What is PM2.5?

　PM2.5 is a very small particle with a diameter of 2.5 μm (1 μm (micrometer) = 1/1000 of 1 mm) or less floating in the atmosphere. “PM” is an acronym for “Particulate Matter,” which is pollutants, such as soot, dust, and sulfur oxides (SOx), emitted from factories, automobiles, ships, and aircraft.
　Since PM2.5 has a very small particle size, it easily penetrates deep into the lungs and is thought to increase the risk of respiratory and circulatory diseases, such as asthma and bronchitis. People with a respiratory or circulatory disease, the elderly, and children are considered to be more susceptible to PM2.5, so they especially need to be careful about it.

2. When do we need to be careful?

　The annual average level of PM2.5 in Japan is declining due to continued restrictions on soot and smoke generated by factories, business establishments, and other facilities and on emissions from automobiles. However, the PM2.5 level fluctuates depending on the season, and the level tends to increase from March to May. The level is also different depending on the region.
　Click here for a quick estimation of PM2.5 levels in Fukuoka Prefecture (Japanese only).

3. What should we do when a warning is issued?

　When the municipality where you live issues a warning on high PM2.5 levels, respond as follows. In particular, infants, the elderly, and those who have a respiratory or circulatory disorder should respond more carefully according to their own physical condition.
〇When you are outdoors
　Refrain from long hours of strenuous exercise to avoid inhaling large amounts of PM2.5.
  Wear a mask.
〇When you are indoors
　Refrain from going out unnecessarily.
　Minimize ventilation and the opening of windows.