潮州市区臭氧污染变化特征及与影响因子关系分析

VARIATION CHARACTERISTICS OF O3 POLLUTION AND ITS RELATIONSHIP WITH INFLUENCING FACTORS IN THE URBAN AREA OF CHAOZHOU

关键词:  潮州  臭氧  氮氧化物  气象因子  特征

Key words:  Chaozhou  O3  NOx  meteorological factors  characteristics

摘要:

基于2014—2020年潮州市区空气质量监测数据和气象观测数据，应用统计分析、聚类分析等方法，分析了O3浓度的时间变化特征，及其与NOx浓度、气象因子的关系。结果表明：潮州市区O3污染有改善趋势，但是浓度下降速度较缓慢；呈双峰型的月变化特征，主峰在10月份；污染强度呈春季高于秋季的趋势；日变化呈单峰变化，07时出现最低值，随后迅速上升，最大值出现在午后15时，之后浓度又逐渐降低。NO2、NOx浓度与O3浓度变化呈反位相关系，早晨峰值比O3浓度低谷时间推迟1 h；下午低谷比O3的峰值提前1 h。潮州市区在最高气温＞25 ℃、无降水、光照充足（＞8 h）、相对湿度＜80%、风速为1.5~2.0 m/s，吹偏西风和偏东风时发生O3污染的几率较大。O3超标出现在中午到上半夜，中度以上污染出现在下午。上午时段日出后的日照及积温是影响O3浓度增长的主要气象因子，到下午时段，日出后的日照和相对湿度成为影响O3浓度增长的主要因子。NO2浓度对O3浓度变化有较明显的影响。聚类分析表明潮州市区O3污染主要受东北和偏东方向的较远距离传输影响和东南方向的近距离传输影响。

Abstract:

Based on the air quality monitoring data and meteorological observation data collected in the urban area of Chaozhou from 2014 to 2020, this study utilized statistical analysis and cluster analysis to examine the temporal variation patterns of O3 concentration and its relationship with NOx concentration and meteorological parameters. The findings suggest that although the O3 pollution in the urban area of Chaozhou showed signs of improvement, the decline in its density occurred at a slow pace. The monthly variation of O3 intensity exhibited a bimodal pattern, with the primary peak in October. Furthermore, the intensity was higher in spring. The diurnal variation of O3 concentration displayed a single peak, with the lowest value observed at 7 o’clock, followed by a rapid increase. The maximum concentration was recorded at 15 o’clock in the afternoon, after which the level gradually decreased. On the other hand, the variation in NO2 and NOx density exhibited an inverse phase relationship with O3. The peak density of NO2 and NOx occurred one hour later than that of O3, while the afternoon trough appeared one hour earlier than the peak of O3. In the Chaozhou urban area, O3 pollution was more likely to occur when the maximum temperature exceeded 25℃, there was no precipitation, there was sufficient sunlight (more than 8 hours), the relative humidity was below 80%, the wind speed ranged from 1.5—2.0 m s-1, and the wind direction was westerly or easterly. O3 concentration exceeded the standard from noon until early midnight, with moderate pollution occurring predominantly in the afternoon. The primary meteorological factors influencing the growth of O3 concentration varied between morning and afternoon. In the morning, sunshine and accumulated temperature were the main factors, while sunshine and relative humidity became the main factors in the afternoon. The concentration of NO2 greatly affected the changes in O3 concentration. Additionally, cluster analysis revealed that O3 pollution in the Chaozhou urban area was primarily influenced by long-distance pollutant transport in the northeast and east directions, as well as short-distance pollutant transport in the southeast direction.