Please be careful about photochemical smog

Nitrogen oxides and other substances emitted into the atmosphere from factories, business establishments, and automobiles undergo chemical reactions with the ultraviolet rays contained in the sun's rays and become substances called "photochemical oxidants." This refers to a state in which the air is not diffused and stays in the atmosphere, making the sky look hazy and white.

Please be aware that photochemical smog is more likely to occur on days with strong sunlight, high temperatures, and weak winds from June to September. It may irritate your eyes and throat, and you may experience symptoms such as "flickering eyes" and "sore throat." When information about photochemical smog is provided, please be careful not to suffer health damage due to photochemical smog, such as refraining from outdoor activities as much as possible.

The Bureau of the Environment, Tokyo Metropolitan Government, sends information such as photochemical smog warnings by e-mail when the oxidant concentration at a reference measurement point exceeds the standard issued in an emergency. See below for details.