润色这段话：At each round of clinical visit blood samples were obtained from each participant Firstly 32 subjects who completed the first the higher PM levels and the third visits the lower PM levels were s

During each clinical visit, blood samples were collected from all participants. To conduct untargeted metabolomics analysis, 32 subjects who had completed the first visit (with higher PM levels) and the third visit (with lower PM levels) were selected. Additionally, the serum levels of ceramide C16:0, C18:0, C20:0, C24:0, and C24:1 were measured in all 152 participants. Furthermore, a range of outcome measures that have been linked to the development and worsening of atherosclerosis were assessed.