We all know that secondhand and even thirdhand smoke from cigarettes is harmful, but what about the smoke emitted from the commercial cooking process?

A new study presented at the national meeting of the American Chemical Society in San Francisco on March 23 shows that abstaining from eating fast foods such as burgers and fries isn’t enough to protect you from their ill effects. Health Day reports that the study, led by professor Deborah Gross of Carleton College, demonstrates how certain restaurants emit smoke and aerosol particles that not only affect air quality, but also contain known carcinogens.

Gross and her team measured and compared solid and liquid aerosol particles emitted while cooking various foods with commercial appliances such as ovens, broilers and griddles. They found that fatty foods cooked at high heat — especially those cooked over open flames — produced the highest levels of emissions. Big offenders included hamburger and fried chicken: Every 1,000 pounds of cooked hamburger resulted in 25 pounds of emissions, while 1,000 pounds of chicken fried in peanut oil produced a whopping 45 pounds of dangerous air pollution. Less offensive was pizza, which only resulted in 3 pounds of emissions for every 1,000 pounds cooked.

Gross expects that her research may lead to more informed methods of food-related emission control.

Also on MNN: Want to support healthier, more environmentally friendly fast-food restaurants? Check out our Top 10 organic fast-food restaurants.