Department of MOE Key Laboratory of Oasis Ecology, Xinjiang University, Urumqi, China.
College of Resources and Environment Science, Xinjiang University, Urumqi, China.
PeerJ. 2022 Mar 30;10:e13203. doi: 10.7717/peerj.13203. eCollection 2022.
PM, which refers to fine particles with an equivalent aerodynamic diameter of less than or equal to 2.5 µm, can not only affect air quality but also endanger public health. Nevertheless, the spatial distribution of PM is not well understood in data-poor regions where monitoring stations are scarce. Therefore, we constructed a random forest (RF) model and a bagging algorithm model based on ground-monitored PM data, aerosol optical depth (AOD) and meteorological data, and auxiliary geographical variables to accurately estimate the spatial distribution of PM concentrations in Xinjiang during 2015-2020 at a resolution of 1 km. Through 10-fold cross-validation (CV), the RF model and bagging algorithm model were verified and compared. The results showed the following: (1) The RF model achieved better model performance and thus can be used to estimate the PM concentration at a relatively high resolution. (2) The PM concentrations were high in southern Xinjiang and low in northern Xinjiang. The high values were concentrated mainly in the Tarim Basin, while most areas of northern Xinjiang maintained low PM levels year-round. (3) The PM values in Xinjiang showed significant seasonality, with the seasonally averaged concentrations decreasing as follows: winter (71.95 µg m) > spring (64.76 µg m) > autumn (46.01 µg m) > summer (43.40 µg m). Our model provides a way to monitor air quality in data-scarce places, thereby advancing efforts to achieve sustainable development in the future.
PM，是指当量空气动力学直径小于或等于 2.5μm 的细颗粒物，不仅能影响空气质量，还会危害公众健康。然而，在监测站稀少的数据匮乏地区，人们对 PM 的空间分布情况了解并不充分。因此，我们构建了一个基于地面监测的 PM 数据、气溶胶光学厚度（AOD）和气象数据以及辅助地理变量的随机森林（RF）模型和袋装算法模型，以在 1km 的分辨率下，准确估计 2015-2020 年新疆地区 PM 浓度的空间分布。通过 10 折交叉验证（CV），对 RF 模型和袋装算法模型进行了验证和比较。结果表明：（1）RF 模型具有更好的模型性能，因此可以用于估计相对较高分辨率的 PM 浓度。（2）新疆 PM 浓度南高北低。高值主要集中在塔里木盆地，而新疆北部大部分地区全年保持低 PM 水平。（3）新疆 PM 值具有显著的季节性，季节平均浓度依次降低：冬季（71.95μg m）>春季（64.76μg m）>秋季（46.01μg m）>夏季（43.40μg m）。我们的模型为监测数据匮乏地区的空气质量提供了一种方法，从而推进未来实现可持续发展的努力。
