The concentration of ozone gas at 52 sampling points in Padang City can be seen in Fig. 3. The concentration of ozone gas measured ranged from 6.32 to 87.06 μg/Nm3. The highest concentration of ozone gas at Padang City is in the 52 sampling points are located in Point 52 at Teluk Bayur area. Ozone gas concentration measured at that point is equal to 87.06 μg/Nm3. The lowest ozone gas concentrations measured at Padang City is equal to 6.32 μg/Nm3 at 48 sampling points located in Bukit Gado-Gado. The average concentrations of measurement is 25,67 μg/Nm3. The highest concentration of ozone gas was measured at 87.06 μg/Nm3, where the concentration is still below the quality standard. It shows that the concentration of ozone in the area of Padang is in the range that does not harm the air.
Referring to research [1] who shows measurements of ozone gas at Pasar Raya Padang, a score of ozone gas concentration higher than the concentrations measured at the sampling point near Pasar Raya, in this study, namely point 43 are located in Berok Nipah. The concentration of ozone gas at point 43 of 29.44 μg/Nm3, whereas the average concentration of ozone gas lows measured by [1] on the morning of 44.1 μg/Nm3. The difference in the measured concentrations of ozone gas at Padang City on this study and previous studies are due to differences in sampling site conditions. Berok Nipah area whose location is about 1.5 miles from Pasar Raya, an area with quite different conditions with Pasar Raya Padang. Pasar Raya is a trading center at Padang City with high human activity and high transportation every day. The difference in these conditions will affect the factors that affect the ozone concentration causing concentration difference obtained at these two locations.