Gallery of Air Gallery of Air This smokestack is releasing greenhouse gases and other pollutants into the atmosphere. Pollution from cars and factories can create dense smog in cities. Photo credit: Metro Transportation Library and Archive. A car’s emissions are checked at a station in California. Photograph by R. Couse-Baker. An oil refinery in Salt Lake City burns off waste gases, releasing carbon dioxide to the atmosphere. Photograph by R. B. Reed. Burning 110 gallons of gasoline will produce one metric ton of carbon dioxide, enough to fill this green balloon in front of the United Nations building. Burning one gallon of gas produces 20 pounds of carbon dioxide. Photo credit: www.TheEnvironmentalBlog.org. An underwater oil pipeline burns after a collision with a tugboat. Photograph by Petty Officer 3rd Class Carlos Vega/US Coast Guard District 8.