There are two kinds of smog: Industrial and photochemical Industrial smog: sulfur dioxide and sulfuric acid Photochemical smog: nitrogen oXides, ozone and hydrocarbons from internal combustion engine 50 Fig 17. 8 the average daily concentration of O130 nitrogen monoxide, z120 nitrogen dioxide, and ozone in Los Angeles 10 night sunrise noon sunset night ppm= parts per million Catalytic converters reduce automobile emissionsThere are two kinds of smog: Industrial and photochemical Industrial smog: sulfur dioxide and sulfuric acid Photochemical smog: nitrogen oxides, ozone and hydrocarbons from internal combustion engine. Catalytic converters reduce automobile emissions Fig 17.8 the average daily concentration of nitrogen monoxide, nitrogen dioxide, and ozone in Los Angeles *ppm = parts per million night sunrise noon sunset night NO,NO 2,O 3(ppm)