A Panel Study On Exposure Of PM_2.5-bound Metals Induced Cardiovascular Damage To Young People

Objectives Exposure to fine particulate matter(PM_2.5)can increase the risk of cardiovascular disease,but the underlying mechanism remain unclear.Although the content of PM_2.5-bound metal elements is low,they have attracted much attention because of their strong toxicity.At present,some research results have been obtained on exposure of susceptible population,few studies have been reported on young people populations.In order to explore the effects of short-term exposure to PM_2.5 and PM_2.5-bound metals on cardiovascular system of young people,this study designed a panel study of healthy college students carried out in typical areas to evaluate the seasonal characteristics of personal exposure concentrations of PM_2.5 and PM_2.5-bound metals,and to explore the dose-response relationship between personal exposure concentration and health effects,then to screen early biomarkers related to exposure and biological effects.Methods In this study,North China University of Technology(Caofeidian campus)was set up as the research field to monitor PM_2.5 concentrations in classrooms and campus environments from 2017 to 2018.45 healthy college students were recruited as the subjects with physical examination and follow-up carried out in four seasons.The time-activity pattern questionnaire was used to obtain the indoor and outdoor exposure time of the subjects,and the personal exposure levels of PM_2.5 and PM_2.5-bound metals were evaluated using the time-weighted model.The associations of personal exposure concentration of PM_2.5 and 15PM_2.5-bound metals with a soluble modality of CD36(s CD36),C-reactive protein(CRP),oxidized low-density lipoprotein,heart rate and blood pressure level were analyzed using four linear mixed-effect models(single-constituent model,constituent-PM_2.5 joint model,single-constituent residual model and residual-PM_2.5 joint model).Results 1 The order of the median concentrations of indoor and outdoor PM_2.5 in Caofeidian was winter>spring>summer>autumn,while the median concentrations of most elements in indoor and outdoor PM_2.5 reached the highest in winter,followed by spring,autumn and summer.The median concentrations of personal PM_2.5exposure in winter,spring,summer and autumn were 93.1?g.m^-3,50.9?g.m^-3,42.9?g.m^-3 and 27.2?g.m^-3,respectively,and the seasonal differences of personal exposure concentrations of 15 metal elements were statistically significant(P<0.001).The I/O ratio analysis of indoor and outdoor concentrations of PM_2.5 and PM_2.5-bound metals showed that indoor concentrations of other elements derived from outdoor sources except Cr,Cu and Mo in four seasons,and the indoor concentrations of PM_2.5and most metal elements in winter and spring were lower than outdoor concentrations.2 It showed that personal metal exposure concentrations had hysteresis effects on the levels of s CD36 and PP(pulse pressure,PP)by linear mixed-effect models analysis,and change was relatively stable among the four models.At 1 day lag,the personal exposure concentrations of V,Ni or Se had a significant positive association with s CD36 level,while the personal exposure concentrations of Cu,As,Cd,Sb or Pb had a significant negative association with s CD36 level(P<0.05).At the lag 2 days,the personal exposure concentrations of Zn,As,Se,Cd or Pb had a significant positive association with s CD36 level,while the personal exposure concentration of Co had a significant negative association with s CD36 level in the four models(P<0.05).After a lag of 3 days,the personal exposure concentrations of V,Cr,Ni or Cu had a significant positive association with s CD36level,while the personal exposure concentrations of Mn,Mo or Sb had a significant negative association with s CD36 level(P<0.05).At 1 day lag,the personal exposure concentrations of As,Cd or Pb had a significant positive association with PP level,while the personal exposure concentrations of V or Se had a significant negative association with PP level in the four models(P<0.05).At the lag 2 days,the personal exposure concentration of Co had a significant positive association with PP level,while the personal exposure concentrations of Zn,Se,Cd or Pb had a significant negative association with PP level(P<0.05).After a lag of 3 days,the personal exposure concentrations of Mo or Sb had a significant positive association with PP level,while the personal exposure concentrations of V,Cr,Ni or Cu had a significant negative association with PP level(P<0.05).The results also showed that the personal exposure concentration of Cu had a significant positive association with CRP level(P<0.05),for each one interquartile range increase of the personal exposure concentration of Cu was associated with 19.4%,19.7%,11.6% and 18.8%increase in the CRP,respectively.Conclusions 1 The median concentrations of PM_2.5,Mn,Cu,Zn,As,Cd,Sb and Pb in Caofeidian were the highest in winter,and the indoor pollution sources mainly originated from outdoor sources.Personal exposure concentrations of 15 PM_2.5-bound metals showed seasonal differences.The median concentrations of personal exposure Mn,Cu,Zn,As,Se,Mo,Cd,Sb and Pb were the highest in winter,and the median concentrations of personal exposure V,Cr and Ni were the highest in summer.2 Linear mixed effects model analysis results showed that personal metal exposure concentrations had hysteresis effects on the levels of s CD36 and PP.s CD36 and PP could be considered as quantitative indicators to evaluate cardiovascular disease by the impact of short-term exposure to PM_2.5-bound metals.Figure 11;Table 10;Reference 163...