Comparison of monthly average concentrations of PM10, NO2, and SO2 during haze and non–haze periods is shown in Figure 1. The highest PM10 levels during haze and non–haze periods were 150.3 μg/m3 in October and 99.2 μg/m3 in December, respectively.The highest NO2 and SO2 levels during haze periods were both found in December, which turned out to be 80.7 μg/m3 and 79.6 μg/m3, respectively. The respective highest levels during non–haze periods were 56.1 μg/m3 in March and 41.6 μg/m3 in December.