帮我润色这段话：Objective Ambient air pollution is a key risk factor for atherosclerotic cardiovascular disease; however the biological mechanisms of air pollution-induced atherosclerosis remain unclear Recen

Objective: Ambient air pollution is a significant risk factor for atherosclerotic cardiovascular disease, yet the underlying biological mechanisms of air pollution-induced atherosclerosis remain unclear. Recent research suggests that sphingolipid metabolism disorder may play a crucial role in atherosclerosis development. Our study aimed to examine the effects of short-term ambient air pollution exposure on sphingolipid metabolism and pro-atherosclerotic responses, and to investigate the potential mediating role of key sphingolipid molecules on the pro-atherosclerotic effects of air pollution exposure.

Methods: We conducted a prospective panel study of 152 participants, with four monthly visits from September 2019 to January 2020. Continuous measurements of ambient air pollutants were taken throughout the study period, including particles in size fractions of 5.6-560.0 nm, fine particulate matter (PM2.5) and its major chemical components (black carbon [BC], organic aerosols [OA], nitrate, sulphate, ammonium and chlorine), and gaseous pollutants (nitrogen dioxide [NO2], sulfur dioxide and carbon monoxide [CO]). Positive Matrix Factorization models were applied to assess the potential sources of OA.