基于一个发现污染类核心区域的聚类模型的大气污染情况分析

由于污染源受地形、地貌及气象等条件影响而分布多样,大气污染数据在空间中呈任意形状、任意密度的复杂分布。为探究这种大气污染分布状况,基于DP算法提出了1个发现污染类核心区域的聚类模型。以实现对污染数据不经统计直接聚类,在保持空气污染数据分布特征不变的基础上提取出关键污染数据,更准确地挖掘空气污染变化规律。将所提聚类模型和k-Means算法在由兰州市2017,2019,2021年各年1月污染物浓度小时数据构成的3个数据集上进行了对比分析。结果显示:所提模型在以上3个数据集上均能更清晰地挖掘出污染数据,在污染类核心区域中的关键污染数据分别为59.0%、57.2%和69.0%,且造成污染的首要污染物均为NO₂和颗粒物。此外,该模型从兰州市2021年1月数据中解析出,兰州市月污染变化由污染物NO₂和PM₁₀共同作用或交替作用引起,日污染变化在受污染小时数和首要污染物(NO₂和PM₁₀)出现次数上的变化趋势均呈双峰型,污染区域为城关区。并通过分析上述污染规律的成因,证明该模型在确保数据复杂分布不变的情况下提取关键污染数据的有效性。

ANALYSIS OF AIR POLLUTION BASED ON A CLUSTERING MODEL FOR DISCOVERING THE BACKBONE OF POLLUTION CLUSTER

Since the distribution of air pollution sources is influenced by topography, landform and meteorology, the distribution of air pollution data in space is of arbitrary shapes and densities. To more accurately mine the rule of air pollution, this paper proposed a clustering model based on the DP algorithm for discovering the backbones of the cluster. The model could directly group pollution data without statistical analysis and extract key information from air pollution data by keeping the distribution unchanged, so as to excavate the change law of air pollution more accurately. The proposed clustering model and the k-Means algorithm were compared and analyzed on the three hourly pollutant concentration datasets monitored in January of 2017, 2019 and 2021 in Lanzhou respectively. In these three datasets, our model could more clearly mine the pollution data. The key pollution data accounted for 59.0%, 57.2% and 69.0% respectively in the backbones of pollution cluster, and the primary pollutants causing pollution were NO₂ and particulate matter. To reflect the applicability of the model, we analyzed our model on the pollution data in Lanzhou in January 2021, then found that the variation of air pollution in that month was caused by the joint or alternate action of pollutants NO₂ and PM₁₀, the hourly variation trend of pollution showed a bimodal pattern both on the number of contaminated hours and the occurrence frequency of primary pollutants (NO₂ and PM₁₀), and Chengguan District was the polluted area. The validity of the model was tested using the causes analysis of the above pollution laws, which made the model practical and effective for extracting key air pollution data without changing its complex distribution.