Hong Kong air pollution hits severe level in Tuen Mun amid weak winds

The Environmental Protection Department (EPD) reported higher-than-normal air pollution today, with the Air Quality Health Index reaching the "Serious" health risk category level of 10+ at the Tuen Mun general monitoring station Tuesday afternoon.

Weak winds across the city hindered the dispersion of pollutants, while abundant sunshine fueled photochemical smog formation, rapidly producing ozone and fine suspended particles across the Pearl River Delta region. Elevated ozone levels also accelerated the formation of nitrogen dioxide.

The Hong Kong Observatory forecasts a moderate easterly airstream will gradually affect the Guangdong coast tomorrow.

Until then, the department expects air pollution to remain higher than usual.

At the "Very High" range or above, children, the elderly, and people with heart or respiratory conditions should minimize or avoid strenuous outdoor activities.

The general public is advised to reduce outdoor physical exertion and limit time spent outdoors, especially in busy traffic areas.

The Education Bureau urged schools to follow its website guidelines to protect student health and monitor index changes.

Employers of outdoor manual workers should assess risks and implement protective measures—such as reducing strenuous outdoor work and time spent outside in traffic-heavy areas—when the index is “very high.”

At the “serious” level, these precautions are required for all outdoor employees.