Changes over time, such as the number of photochemical smog warnings issued

　Environmental standards have been set for the concentration of photochemical oxidants, which is an indicator of whether photochemical smog is occurring, but few measuring stations meet environmental standards nationwide. There are about 1200 measuring stations that measure photochemical oxidants nationwide, of which 6 are often met with environmental standards, and 0 are years old.
　Kanagawa Prefecture has established the issuing standards for photochemical smog advisories.

• The number of photochemical smog warnings, etc. that occur in one year is greatly affected by summer weather conditions (heat intense heat, cold summer, long rain, to plum rain, etc.), and tends to be large in hot summer years and low in cold summer years . For this reason, the number of photochemical smog warnings issued in the Yokohama city area also varies depending on the year.
• The number of photochemical smog warnings was the highest number of issued in 1973 (Showa 48).
• Photochemical smog warnings have been issued twice in Yokohama (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 in 2021. Was.
• The largest number of reported victims was 6,175 in 1975 (Showa 50).