A smog alert was issued for Prague and the Central Bohemian Region after ozone levels exceeded safe limits.
The warning, issued by the Czech Hydrometeorological Institute (ČHMÚ), remains in effect until further notice. It comes as the country continues to experience exceptionally hot weather, which has created ideal conditions for ozone formation.
According to meteorologists, the alert was declared after monitoring stations recorded hourly average ozone concentrations above the information threshold of 180 micrograms per cubic meter. Forecasters expect similar levels to continue at some measuring stations, meaning the health warning is likely to remain in place.
Ground-level ozone is not emitted directly into the atmosphere. Instead, it forms when pollutants such as nitrogen oxides and hydrocarbons react under strong sunlight. Heatwaves often accelerate this process, leading to higher concentrations, particularly during the afternoon.
Health officials advise people to avoid intense physical activity outdoors while ozone levels remain elevated. The recommendation is especially important for children, older adults, and people living with chronic respiratory illnesses, who are more vulnerable to air pollution.
Exposure to high levels of ozone can irritate the lungs and mucous membranes. Common symptoms include coughing, burning eyes or nose, headaches, and a feeling of pressure in the chest. Prolonged exposure may worsen existing respiratory conditions.
The latest warning follows a similar alert issued on Friday for the Ústí nad Labem Region.
At the time, meteorologists indicated that additional regions could also be affected if weather conditions remained unchanged. Sunday’s announcement confirms those concerns as the heatwave continues across much of the country.
Authorities recommend following official weather updates and reducing outdoor exertion until air quality improves.
