重庆主城区大气污染物时空变化及影响因素分析

发布时间：2018-06-24 19:20

本文选题：大气污染物 + 时空变化　；参考：《重庆师范大学》2017年硕士论文

【摘要】：日益严重的城市大气污染,给生态环境和人类健康带来了严重的危害。重庆主城区是典型的山地城市,由于其特殊的山地地形和气象条件等因素综合影响,大气污染扩散缓慢。本文利用重庆主城区2015-2016年17个大气环境质量监测站点的大气污染物浓度数据以及同期虎溪镇气象站的气象数据,综合运用小波变换、空间插值、轨迹聚类等方法,分别从不同的时间尺度和空间尺度对主城区大气污染物的时空变化特征及其影响因素进行了研究。得出了如下的研究结果:1除O_3外,重庆主城区大气污染物的逐日变化趋势多呈U型。大气颗粒物浓度的逐月变化趋势为“单峰单谷”型,高浓度月份主要是1和2月,低浓度月份为7和8月。NO_2、SO_2、CO浓度变化趋势相对较为平缓,浓度高值与低值出现月份与颗粒物出现月份相近;O_3浓度大致呈双峰型变化趋势。季节变化特征方面,除O_3外,其他均呈现出冬季高,夏季低的特征。颗粒物浓度大小为冬春秋夏,NO_2、SO_2、CO浓度大小排序为冬秋春夏,O_3则正好相反。小波分析结果来看,2015年-2016年间,PM_(2.5)和PM_(10)均存在五个尺度的周期变化规律,第一主周期为183d左右。NO_2、SO_2、CO和O_3均有3类以上的周期变化规律,第一主周期分别为183d、182d、181d和161d。2重庆主城区PM_(2.5)、PM_(10)、NO_2浓度空间分布上表现为南高北低,高值区主要集中在城区中西部,低值区主要在西北部的缙云山和北部的城市郊区。SO_2空间分布表现为由南向北逐渐递减,南部高值区主要在巴南区的西南部。CO浓度呈破碎状的块状分布,浓度低值区出现的地方多为山地地形。O_3浓度空间分布情况正好与NO_2相反,西北高,中西部浓度低。不同季节的空间分布上,PM_(2.5)浓度空间分布特征主要表现为中部城区浓度偏高,西北部及城市郊区浓度偏低,浓度差异冬高夏低。O_3浓度分布情况与PM_(2.5)正好相反。3人口密度、房屋建筑面积与PM_(2.5)、PM_(10)、NO_2呈显著正相关,与O_3、SO_2以及CO多呈负相关;而与交通公路里程虽呈负相关,但相关性不显著。PM_(2.5)、PM_(10)、NO_2、SO_2、CO与大气温度、湿度、总辐射、降水量以及风速呈负相关,与大气压强、风向呈正相关。在日降水量不足5mm时,清除能力较小;超过5mm时,清除能力随降雨量增大而增大。夏季降水强度的总体平均清除率由小到大依次为O_3NO_2PM_(2.5)SO_2PM_(10)。5h以下时长降水对大气污染物的平均清除率为负;5~10h、10~15h和15~20h时长降水分别对PM_(10)、NO_2和SO_2的平均清除率最高。夏季降水时长的总体平均清除率大小依次为SO_2PM_(10)NO_2PM_(2.5)O_3。累积降水量大小与颗粒物浓度多呈显著负相关。4轨迹聚类分析结果来看,西部方向的轨迹4为主城区冬季的主要输送路径,气流轨迹数量占总轨迹数的54.95%。冬季污染物浓度主要受来自西藏、四川等气流输送的影响,但重庆地区的本地污染源排放的影响仍不可忽视。三次重污染过程中,空气污染主要受来自于近地面运行路程较短、移动速度较慢的西南气团、西北和东南气团影响。
[Abstract]:The increasingly serious urban air pollution has brought serious harm to the ecological environment and human health. The main city of Chongqing is a typical mountain city. The atmospheric pollution is slow to spread because of its special mountainous terrain and meteorological conditions. This paper uses the 17 atmospheric environmental quality monitoring stations in the main city of Chongqing for 2015-2016 years. The atmospheric pollutant concentration data and the meteorological data of the meteorological station in the same period have been studied by the methods of wavelet transform, spatial interpolation and trajectory clustering. The spatial and temporal characteristics of air pollutants in the main urban area and its influencing factors are studied from different time scales and spatial scales. The following results are obtained: 1 O_3 In addition, the daily change trend of air pollutants in the main urban area of Chongqing is mostly U type. The monthly change trend of atmospheric particulates concentration is "single peak single valley" type. The month of high concentration is mainly 1 and February, the month of low concentration is 7 and August, and the change trend of SO_2, CO concentration is relatively gentle, and the high and low concentration month and the month of particles appear in the month of high concentration and low value. The concentration of O_3 is approximately the trend of Shuangfeng type. In terms of seasonal variation, except O_3, all other features are high in winter and low in summer. The concentration of particles is in winter, spring and autumn, NO_2, SO_2, and CO concentration is in winter and autumn in spring and summer, and O_3 is just the opposite. The results of wavelet analysis showed that PM_ (2.5) and PM_ (10) were stored in -2016 in 2015. In the periodic variation of five scales, the first principal period is about 183d.NO_2, SO_2, CO and O_3 have more than 3 kinds of periodic variation. The first main period is 183d, 182d, 181d and 161d.2 Chongqing main city region PM_ (2.5), PM_ (10), and the spatial distribution of NO_2 concentration is low in South High North, and the high value area is mainly concentrated in the Midwest, low value area of urban area. The spatial distribution of.SO_2 spatial distribution in the north-west Jinyun Mountain and the northern suburb is gradually decreasing from south to north. The South high value area is mainly in the southwestern part of the Banan region, the concentration of.CO in the southwestern part of the Banan region is fractured and massive. The location of the low concentration area is mostly the spatial distribution of the.O_3 concentration in the mountain terrain, which is opposite to the NO_2, the northwest is high, the West and the West are high. The spatial distribution of PM_ (2.5) concentration in different seasons showed that the concentration of the concentration in the central urban area was high, the concentration in the northwest and the suburb was low, the concentration difference between the winter high summer and the low.O_3 concentration and the PM_ (2.5) was just the opposite of the.3 population density, and the building area was significantly positively correlated with PM_ (2.5), PM_ (10), and NO_2. Negative correlation with O_3, SO_2 and CO, but negative correlation with traffic road mileage, but the correlation is not significant.PM_ (2.5), PM_ (10), NO_2, SO_2, CO are negatively correlated with atmospheric temperature, humidity, total radiation, precipitation and wind speed, and are positively correlated with atmospheric pressure and wind direction. When the daily precipitation is less than 5mm, the ability to scavenge is smaller than 5mm, clearance energy exceeds 5mm. The average scavenging rate of precipitation intensity in summer is O_3NO_2PM_ (2.5) SO_2PM_ (10).5h and the average clearance of precipitation is negative for atmospheric pollutants, and the average removal rate of PM_ (10), NO_2 and SO_2 is the highest in 5~10h, 10~15h and 15~20h. The average scavenging rate is SO_2PM_ (10) NO_2PM_ (2.5) O_3. cumulative precipitation and the concentration of particulate matter in a significant negative correlation.4 trajectory clustering analysis results, the western direction of the track 4 is the main transportation path in the main urban area in winter, and the concentration of air flow trajectory in the total number of 54.95%. in winter is mainly from Tibet, The impact of Sichuan and other airflow transport, but the impact of the local pollution sources in the Chongqing area can not be ignored. In the three heavy pollution process, air pollution is mainly affected by the south-west air mass, the southwest and the southeast air mass, which have short running distance in the near ground and slow moving speed.
【学位授予单位】：重庆师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X51

【参考文献】