Residents living in Bulgaria and Poland may want to consider relocating. The latest annual air quality report published by the European Environment Agency (EEA) disclosed on Tuesday that the two countries have the worst and dirtiest air quality among all of Europe.

Between the two EU nations, Bulgaria has the highest concentrations of the two major varieties of particulate matter, as well as carbon monoxide and sulfur dioxide. Particulate matter are described as tiny airborne droplets or gas particles that come from a variety of sources, including smokestacks and vehicle tailpipes. Exposure to these lead to many health problems including asthma and cancer.

The pollution in Bulgaria has been described by Alex Melamed as almost incredible.

"When you put on a washed white shirt and take a walk for a couple of hours in Sofia, when you come back you can see that the collar and the front have a yellow-gray hue," the 25-year-old business student told New York Times. "Sometimes I do the following experiment: I walk around in Sofia and do not touch anything, when I come back and wash my hands, the soap gets dirty."

Broken down by cities, the report said that four of Europe's five cities have the highest levels of particulate matter were all found in Bulgaria. Pernik topped the list as the dirtiest city. High concentrations of particulates were found to have been present and hanging in the air half of the year in the small city just southwest of the capital, Sofia.

Valentin Foltescu, an air quality expert at the EEA, points the country's use of wood for domestic requirements as culprit of the problem.

"Populations are switching to domestic fuels when they can't afford energy prices," he said.

The agency however did not dismiss that air pollution may also be "imported" by wind from neighboring countries.

Overall, more than 90 per cent of people in European cities breathe in dangerous air, the report said, noting it has shortened 430,000 lives annually every year.

"European citizens often breathe air that does not meet the European standards," the EEA said.

"Particulate matter remains a serious threat to health, because no threshold for PM has been identified below which no damage to health is observed. In Western, Central and Eastern Europe it was 430,000 premature deaths," the study found.