Changes in the number of photochemical smog advisory issuance

　Environmental standards have been set for the concentration of photochemical oxidants, which are indicators of whether photochemical smog is occurring, but there are few measuring stations that meet environmental standards even when viewed nationwide. There are about 1200 measuring stations nationwide measure photochemical oxidants, of which 6 meet environmental standards even in many years, and there are 0 stations.
　Kanagawa Prefecture has established the standards for issuing photochemical smog warnings.

• The number of photochemical smog warnings that occur in one year is greatly affected by summer weather conditions (hot summer, cold summer, long rain, plum rain, etc.), and is more common in intense heat years and less in cold summer years There is. For this reason, the number of photochemical smog alerts issued in Yokohama city area also fluctuates from year to year.
• The highest number of photochemical smog warnings was issued in 20 in 1973 (Showa 48).
• Photochemical smog alerts have been issued twice to Yokohama City (1975 and 1978).
• A serious emergency warning has never been issued in Kanagawa Prefecture.

• In recent years, the number of health victims reported to Yokohama City was 226 in 2005, 166 in 2006, 2 in 2008 and 2009, 59 in 2013, and 2 people in 2021.
• The largest number of reported victims was 6,175 in 1975 (Showa 50).