Please be cautious of photochemical smog

What is photochemical smog?

Nitrogen oxides and other substances emitted into the atmosphere from factories, businesses, and automobiles undergo chemical reactions due to ultraviolet rays contained in sunlight, resulting in substances known as "photochemical oxidants." When these substances do not disperse in the atmosphere and remain stagnant, it causes the sky to become hazy, creating a state that resembles a white mist.

Period when photochemical smog is likely to occur

From June to September, strong sunlight, high temperatures, and weak winds can easily lead to the occurrence of photochemical smog, so please be cautious. Symptoms such as eye irritation and sore throat may occur, including "eyes feeling strained" and "throat pain." When information about photochemical smog is provided, please take care to avoid health hazards related to photochemical smog by minimizing outdoor activities as much as possible.

Information about Photochemical Smog

The Tokyo Metropolitan Environmental Bureau distributes information such as photochemical smog alerts via email when the oxidant concentration at the standard measurement points exceeds the emergency issuance criteria. For more details, please see below.

• Tokyo Photochemical Smog Information(External Link)