The Environment Ministry Thursday issued a warning about air pollution in Attica, caused principally by a cloud of dust from North Africa, and asked vulnerable citizens with respiratory problems or heart ailments, as well as children and over-65s to avoid strenuous physical exercise and spend as little time as possible outdoors.
Authorities in Western Macedonia issued a warning on Tuesday about high smog levels in the region caused by the large number of households using fireplaces to keep warm.
According to regional authorities, atmospheric pollution in the municipalities of Kozani, Eordaia, Amyntaio and Florina have risen above the warning level.
The Environment Ministry has called on Athenians to avoid burning wood and other organic materials in fireplaces and boilers as air pollution in the city has reached dangerous levels.
In a statement, the ministry said that weather conditions are conducive to the buildup of smog over the city.
Updates will follow if conditions change, it said.
The Maritsa Iztok-2 Thermal Power Plant (TPP) is topping by far a European list of the continent's most pollutive industrial facilities, a report published Tuesday shows.
This is one position up compared to 2009, when Bulgaria's biggest TPP was second.
The ranking is about the size of pollution costs the heavy industry carries to citizens.
Bulgaria remains the leader in the European Union in terms of air pollution, according to the World Health Organization.
The highest concentration of the two main types of particulates has been measured in Bulgaria, the WHO latest data has showed. Poland and Romania rank second and third in the negative rating.
The cleanest air in Bulgaria is at Rozhen peak in the Rhodope mountains, while the cities Plovdiv and Varna have the most polluted air.
The main cause of air pollution in Bulgaria are the fine dust particles, said the head of the Air Monitoring Department in the State Environment Agency, Valeri Serafimov.
One in eight of total global deaths is the result of air pollution exposure, according to the new World Health Organization report, released Tuesday.
This finding more than doubles previous estimates and confirms that air pollution is now the world's largest single environmental health risk. Reducing air pollution could save millions of lives.