The problem gets much worse when instead of firewood people burn salvaged wood or broken-up furniture that contains noxious varnishes or synthetic coatings.
A University of Thessaloniki study found that the concentration of fine particles in the air of the country’s second-largest city was on average twice the safety level from mid-November to mid-December 2012 — and considerably higher than a year earlier. Fine dust is particularly dangerous as it seeps deep into the lungs, potentially causing respiratory problems.
The Thessaloniki study estimated that the increase in pollution would lead to an extra €40 million ($52 million) burden in public health costs.
In Athens, the crisis had initially helped to improve air quality as high gasoline costs discouraged the use of private transport. That changed this winter, as people rushed to buy firewood — and the immediate outlook is bleak.
‘‘We expect that as temperatures go down in January and February use of fireplaces will increase and the phenomenon will rise,’’ said Evangelos Gerassopoulos, research director at the National Observatory.
The Environment Ministry said this month that while the smog ‘‘creates a serious problem for public health ... at this point the situation is not so acute as to allow taking emergency measures.’’
The Athens Medical Association, however, responded with an urgent appeal for action.
‘‘We can’t wait any longer,’’ it said in a statement. ‘‘We have enough cancers in our country. The cost of treating people sickened from the effects of the smog will be much greater than that of (fully) subsidizing natural gas and heating oil.’’
The government has ruled out an expansion of the current heating oil rebate system. Meanwhile, the vast appetite for wood has encouraged extensive illegal logging — by local residents for private use but also by organized gangs. Reports of clandestinely felled trees have come in even from the suburbs of Athens and a town park in central Greece.
Forestry services, hit so severely by cutbacks that they sometimes lack enough gasoline for car patrols, face the daunting task of policing some 6.4 million hectares (16 million acres) of forest.
Georgios Amorgianniotis, a secretary for forests at the environment ministry, said illegal logging only became a serious problem during the crisis.
He said legal actions against clandestine loggers doubled in 2012 compared to the year before, although that’s partly due to stricter policing. In the area of Mount Olympus, mythical home of the ancient Greek gods, 300 people were arrested last year for illegal logging — a five-fold increase from before the 2009 eruption of Greece’s crisis.
In 2011, officials confiscated more than 6,500 tons of illegally cut firewood. That number doubled last year to 13,100 tons while more than 400 vehicles were impounded.
Forestry workers have even been attacked by illegal loggers wielding axes or guns.
After a shooting incident last year, a foresters’ union weighed in with this judgment: ‘‘It’s clearly turning into a Far West-style situation.’’
Costas Kantouris in Thessaloniki contributed.