Matching points are the direct data sources of the fundamental matrix, camera parameters, and point cloud calculation. Thus, their uncertainty has a direct influence on the quality of image-based 3D reconstruction and is dependent on the number, accuracy, and distribution of the matching points. This study mainly focuses on the uncertainty of matching point distribution. First, horizontal dilution of precision (HDOP) is used to quantify the feature point distribution in the overlapping region of multiple images. Then, the quantization method is constructed. $\overline{HDO{P}^{\ast }}$ , the average of $2\times \arctan \left(HDOP\times \sqrt{\frac{n}{5}}-1\right)/\pi$ on all images, is utilized to measure the uncertainty of matching point distribution on 3D reconstruction. Finally, simulated and real scene experiments were performed to describe and verify the rationality of the proposed method. We found that the relationship between $\overline{HDO{P}^{\ast }}$ and the matching point distribution in this study was consistent with that between matching point distribution and 3D reconstruction. Consequently, it may be a feasible method to predict the quality of 3D reconstruction by calculating the uncertainty of matching point distribution.

Per- and polyfluoroalkyl substances (PFASs) could be attached to particles and transported in the atmosphere, it is necessary to investigate the characteristics of legacy and emerging PFASs in atmospheric particulates in relatively clean, low pollution open ocean in China to reveal the transport mechanism of PFASs in the atmosphere. Concentration characteristics of 30 legacy and emerging in total suspended particulate (TSP, particles with aerodynamic diameters < 100 μm) from Laoshan in Shandong and Xisha Islands in the South China Sea were analyzed. ∑PFASs in TSP ranged in 5.65–80.1 pg/m³ and 3.59–18.2 pg/m³ for Laoshan and Xisha Islands, respectively. Generally, the long-chained PFASs were the most detected PFAS, with the detection frequency of 73.1 % and 72.0 %. Perfluorooctanoic acid (PFOA) were the main PFAS, with the profiles of 57.1 % and 21.0 %, respectively. Principal component analysis and multiple linear regression (PCA-MLR) showed that the Laoshan was dominated by fluoropolymer manufacturing (46.9 %) and metal electroplating/electrochemical processes (36.3 %), while the Xisha islands exhibited primary contributions from textile treatment sources (53.4 %) and precious metal sources (42.2 %). The backward trajectory clusters for 24 h/120 h showed that air masses in the Laoshan primarily originated from northern (23 %) and southeastern (28 %), the Xisha Islands were predominantly sourced from the northeastern (80 %), overlapping transport paths of air masses between the two regions within the same altitude range. This suggests that that the similarity of PFAS distribution characteristics between Laoshan and Xisha may be related to long-distance atmospheric transport between the two regions.