Abstract: Air quality data and relevant meteorological data were used in this paper to analyze the variations of ozone and the meteorology influencing factors in Shanghai in 2017.Studies on subjective synoptic weather classifications on ozone were also conducted.The results showed that there were 275 non-pollution days accounting for 75.3% of the whole year of 2017.There were 55 O₃-8h pollution days.The average O₃-8h concentration was 115 μg·m^-3 in 2017.The year-on-year growth was more than 10%.It has reached the highest concentration since 2013.The increase in ozone concentration in 2017 was mainly due to the increase in ozone concentration in the summer half-year.Compared with the summer half-year of 2016,the conditions of wind,temperature,water vapor,illumination,and radiation were all helpful to increase the ozone concentration in the summer half-year of 2017,which was under the background of the abnormally western and strengthened western Pacific subtropical high.The synoptic systems affecting O₃ pollution are classified into four patterns,including subtropical high (SH),surface high (G),equalized pressure (J) and low pressure (D).The subtropical high pattern is the most predominant and typical ozone pollution pattern,accounting for 29.1% of the total.It shows high level pollution.The low-pressure pattern appears with the least frequency,and the surface high pattern shows the lowest level of pollution.

Key words: Ozone pollution, Meteorological conditions, Synoptic weather classification