摘要：Air pollution in Ogaki City has been studied for more than five years. Measurement on the variation of SO3 and NO2 value was performed at more than thirty places, and the hourly variation of the gases was tested at some places. It was found that air pollution in this city was mainly caused by two sources, one of which was two factory areas in southern and western districts, and another was cars running on the National Road Route 21. It was proved that pollutants discharged from the factories are both sulfur dioxide and hydrogen sulfide, and those from cars are nitrogen oxides, and their concentrations were makedly high. Polluted areas were altered with the wind direction and the main wind direction in this city is between north and west, so the polluted areas are unchanged through all seasons. It was also found that correlation exists between the concentration of sulfur dioxide and the direction of wind.
