Vulnerable groups advised to stay indoors in the afternoon as respiratory hazards rise

Children cool off at a fountain tunnel in Gwanghwamun Square in Seoul. [Yonhap]
Children cool off at a fountain tunnel in Gwanghwamun Square in Seoul. [Yonhap]

Clear skies will cover the country Friday under high-pressure influence, but rising ozone concentrations and intense ultraviolet radiation in the afternoon are expected to pose health risks, particularly for vulnerable groups.

Ozone levels across the country — except Jeju — are forecast to reach "bad" levels Friday afternoon, driven by a combination of ozone carried in from abroad and additional ozone generated domestically.

Ozone forms when nitrogen oxides and volatile organic compounds — emitted by vehicle exhaust and power plant and factory emissions — undergo chemical reactions under strong sunlight.

High ozone concentrations irritate the skin and respiratory tract and can worsen bronchial conditions. People with respiratory illnesses and other vulnerable individuals are advised to avoid going outside in the afternoon.

Ultraviolet radiation is also forecast to reach very strong levels around midday.

Between noon and 3 p.m. Friday, UV rays will be strong enough to cause sunburn within minutes of skin exposure. Those heading out for street gatherings to cheer on the South Korean national team at the 2026 World Cup should take precautions against UV exposure.

Showers of 5 to 10 millimeters are expected in the central and northern inland areas and mountain regions of Gangwon Province between the afternoon and evening.

Temperatures Friday are forecast to range from lows of 12 to 18 degrees Celsius in the morning to highs of 26 to 30 degrees Celsius during the day.

Forecast lows and highs for major cities are: Seoul 16 and 28 degrees, Incheon 17 and 26 degrees, Daejeon 15 and 29 degrees, Gwangju 16 and 29 degrees, Daegu 16 and 30 degrees, Ulsan 17 and 28 degrees, and Busan 17 and 27 degrees.


balme@heraldcorp.com