Over the years, the novelty of wood-burning ovens has become an increasingly prominent trend at restaurants around the world. In May, news broke that the fast-casual chain Applebee’s would be investing $75 million in wood-fired grills to cook chicken, fish, and steak, hoping the new method would give its menu “a sense of freshness and quality.” And for decades pizzerias have enjoyed pulling fresh pies out of giant ovens before their customers’ eyes. Hell, Guy Fieri has a wood-burning pizza oven in his backyard.

Still, a new study published in the September issue of the international journal Atmospheric Environment, claims wood-burning ovens are actually wreaking havoc on the environment. Though the study was conducted by researchers from seven different countries, and included data from several urban areas, the report focuses largely on Sao Paulo, Brazil.

Though Sao Paulo has recently reduced automobile emissions thanks to the adoption of biofuels, scientists found that the pollution in the city was still incredibly high.

“A total of over 307,000 tonnes of wood is burned each year in pizzerias,” Dr. Prashant Kumar, the University of Surrey’s lead researcher on the study, told the Daily Mail on Monday. “This is significant enough of a threat to be of real concern to the environment negating the positive effect on the environment that compulsory green biofuel policy has on vehicles.”

Though wood-fired steakhouses, as well as the practice of burning waste, also contributed to the emissions, the study found that thousands of wood-burning pizzerias were the main culprits. Kumar claims that these pizza restaurants and steakhouses are burning hundreds of acres of Eucalyptus forest every month to stay in business.

“Once in the air, the emitted pollutants can undergo complex physical and chemical processes to form harmful secondary pollutants such as ozone and secondary aerosol,” Yang Zhang, a professor from the North Carolina State University, who also participated in the study, told the Daily Mail. “While most studies in Brazil have focused on impacts of vehicle emissions on air quality and human health, the impacts of emissions from wood/coal burning and meat-cooking in pizzerias and restaurants are yet to be quantified.”

[via Daily Mail]