The Czech Republic has made significant progress in fighting air pollution during the past 10 years, but if gas prices continue to rise, the country's air quality and respiratory health may decline.

Cars are the largest source of pollution in the Czech Republic, but households, particularly home furnaces, are the second-largest polluter, according to a recent study done by the National Institute of Public Health.

While emissions produced by households and companies have been decreasing since 1990, rising gas prices have sparked the return of using cheaper, dirtier fuel sources such as coal, wood and even garbage to heat homes.

Jiří Morávek, bureau chief of air-pollution control at the Environment Ministry, told the Czech press last week that he was surprised that half of the country's air pollution comes from home furnaces. The emissions often contain poisonous substances such as arsenic or cancer-causing polycyclic aromatic hydrocarbons, Morávek said.

"The situation does not have to be as serious if certain rules are observed," said Bohumil Kotlík of the National Institute of Public Health. "For example, you can choose environmentally friendlier sources of energy; recycle trash instead of burning it and so on."

But affordability usually trumps environmental conscience.

"If the price of gas rises and you find out that heating by gas will cost you 40,000 Kč ($1,625) annually, coal will cost you 20,000 Kč and wood 10,000-15,000 Kč, what will you choose?" Kotlík asked.

The institute's study, a continuation of research that began in 2000, was conducted in three villages in different corners of Bohemia after receiving a grant from the Environment Ministry. One village predominantly used coal for heating. The second relied on wood, and the third used a mixture of sources.

The pollution was worst in the village where they burned brown coal, and Kotlík noted that it was comparable to the situation in the industrial Ostrava-Karvína region.

While the study did not measure air pollution in Ostrava or Prague, the number of hydrocarbons in one of the villages was as high as in Ostrava, where the concentration is three to four times higher than in Prague.

"For coal, it depends what type you are using and how you burn it," Kotlík said. "If you use higher-quality coal and burn it in a good system with higher temperatures, environmental damage is far less than in the opposite case. The same applies to wood."

Much depends on the equipment.

"If you go to a store and ask, they will sell you the most expensive one," Kotlík said, "but maybe it is not the most environmentally friendly one."

From 1994 to 2003, the city of Prague spent more than 390 million Kč improving heating technology, according to Jarmila Krebsová, a spokeswoman for the Environment Ministry. "Nearly 38,000 flats had their heating systems changed to more environment-friendly units," Krebsová said. "In 1994, 34 percent of Prague homes were using 'solid' fuel like coal. In late 2003, the number declined to 26 percent."

Home fires burning

A recent environmental performance review of the Czech Republic conducted by the Organization of Economic Cooperation and Development (OECD) confirmed that air quality is still degraded by home fires. Suspended particulate matter, (SPM) which is emitted by home fires, increased during much of the review period and is a major concern, according to the OECD.

Particulate matter, generated from vehicles, incinerators and industrial plants, can harm respiratory organs.

Both the annual average limit and the 24-hour limit were exceeded at about one-fourth of the measuring stations.

"Households returning to cheaper but dirtier heating fuels may explain part of the increase in SPM," according to the OECD report.