近五年内长沙臭氧统计特征及污染气象条件分析

Statistical Characteristics of Ozone and the Meteorological Condition Analysis of Ozone Pollution in Changsha in the Last Five Years

摘要: 利用2015~2019年长沙10个气溶胶站点监测数据及长沙国家基本气象站气象要素数据，统计近五年臭氧浓度变化特征，并分析臭氧污染气象条件。结果表明：(1) 五年内，O₃污染日数、O₃-8 h年平均浓度、O₃-1 h年平均浓度呈现逐年递增的趋势；冬季臭氧浓度最低，春季次之，夏秋季节最高；臭氧浓度月变化表现出单峰分布的特点，其浓度峰值主要出现在每年的8月或9月。(2) O₃小时浓度峰值主要集中在13~17时，浓度谷值出现在7时；NO₂的峰值浓度出现在夜间0时前后，谷值浓度主要集中在13~17时，与O₃峰值浓度时间对应。(3) 臭氧污染的基本气象条件为晴天无雨、风速1~2级、日照5.5小时以上、最高气温28℃~37℃；有利气象条件为晴天无雨、风速1~2级、日照9小时以上、最高气温30℃~35℃。(4)臭氧污染日内，平均气温和最高气温均比非污染日高，雨日所占百分比仅12%，较非污染日偏低约34%；平均日照时数在9小时以上，最小相对湿度 ≤ 40%占比超过了50%，远大于非污染日，平均风速和极大风速也均是臭氧污染日小于非污染日。

Abstract: The statistical characteristics of ozone concentration and the meteorological conditions of ozone pollution in the last five years are analyzed by using the monitoring data of 10 aerosol stations in Changsha and the meteorological data of Changsha National Meteorological Station from 2015 to 2019. The conclusion is as follows: (1) The days of ozone pollution, annual average concentration of O₃-8 h, O₃-1 h are both showing an increasing trend year by year in the last five years; the ozone concentration is the lowest in winter, the second in spring and the highest in summer and autumn; the monthly variation of ozone concentration shows the characteristics of single peak distribution, and its peak concentration mainly occurs in August or September every year. (2) The peak value of ozone hourly concentration is mainly at 13 to17 o’clock, and the valley value appears at 7 o’clock; the peak concentration of Nitrogen dioxide is around 0 o'clock at night, and the valley concentration is mainly between 13 to 17 o’clock, corresponding to the peak concentration time of ozone. (3) The basic meteorological conditions of ozone pollution are sunny days without rain, wind speed between one to two grade, sunshine of more than 5.5 hours, and maximum temperature between 28 to 37 centigrade and the favorable meteorological conditions are sunny days without rain, wind speed between one to two grade, sunshine of more than 9 hours, and maximum temperature between 30 to 35 centigrade. (4) In the ozone pollution days, the average temperature and the maximum temperature are higher than the non-pollution days, the percentage of rainy day is only 12%, which is about 34% lower than the non-pollution days; the average sunshine hours are more than 9 hours, and the minimum relative humidity ≤ 40% is more than 50%, which is far greater than the non-pollution days. The average wind speed and the maximum wind speed in the ozone pollution days are also smaller than in the non-pollution days.