Personal PM_2.5 Exposure And Respiratory Damage: A Panel Study Among Young Adults

Part One Assessment of personal exposure to fine particulate matter based on time-activity patternsObjective: The study aimed to assess personal exposure levels of fine particulate matter(PM2.5) based on data on microenvironmental PM2.5 concentrations and the time-activity patterns, and to investigate associations between the microenvironmental PM2.5 concentrations and PM2.5 personal exposure levels.Methods: Postgraduats(n=20) from a university in Wuhan, China were recruited. Daily PM2.5 concentrations in the microenvironments(including offices, laboratories dormitories, and campus) were measured for continuous seven days in the four seasons, information about personal time-activity patterns were synchronously collected by a questionnaire. Afterwards, change in daily average potential exposure doses of PM2.5(PM2.5 potential exposure dose) was estimated using a generalized mixed linear model.Results: In the four seasons of spring, summer, autumn and winter, the corresponding medians(interquartile range) of PM2.5 potential exposure dose were 784.16(543.24) ?g/day, 639.05(309.35) ?g/day, 1379.39(1091.06) ?g/day and 1722.53(1053.44) ?g/day, respectively. The contribution of PM2.5 in different microenvironments to PM2.5 personal potential exposure dose was sorted as follows: offices>dormitories>laboratories>campus. The daily PM2.5 concentrations in the offices or dormitories was associated with increased potential dose of 24-hour personal PM2.5 exposure(all p<0.05).Conclusions: Daily PM2.5 concentrations in the microenvironments and personal time-actitity pattern affected the potential dose of personal PM2.5 exposure. Indoor PM2.5 had a greater contribution to the potential dose of personal PM2.5 exposure than outdoor PM2.5.Part Two Personal exposure to fine particulate matter and respiratory damage among young adultsObjective: Short-term effects of personal expoure to PM2.5 on respiratory health among young adults were investigeated.Method: Generalized mixed linear model was used to estimate changes in the health indicators including fractional exhaled nitric oxide(Fe NO), C-reactive protein(CRP), serum amyloid A(SAA), interleukin-1?(IL-1?), uteroglobin(UG), forced vital capacity(FVC), forced expiratory volume in one second(FEV1.0), peak expiratory flow(PEF) and maximal voluntary ventilation(MVV), when potential dose of personal PM2.5 exposure increased.Results: As an interquartile range increased(948.38?g/day) in potential dose of personal PM2.5 exposure, Fe NO increased by 9.07%(95% confidence interval(CI): 2.20%, 15.95%) at lag 0 day, 9.04%(95%CI: 1.02%, 17.05%) at lag 5 day, 9.24%(95%CI: 1.08%, 17.40%) at lag 0-3 day and 10.72%(95%CI: 0.01%, 21.43%) at lag 0-4 day, respectively; IL-1? increased by 103.09%(95%CI: 46.95%, 159.23%) at lag 2 day, 95.31%(95%CI: 60.66%, 129.96%) at lag 3 day, 99.86%(95%CI: 35.20%, 164.53%) at lag 0-3 day and 83.50%(95%CI: 17.14%, 149.86%) at lag 0-4 day, respectively; FEV1.0 decreased 1.49%(95%CI: 0.18%, 2.80%) at lag 2 day; MVV decreased 9.60%(95%CI: 4.90%, 14.29%) at lag 2 day, 7.42%(95%CI: 1.18%, 13.65%) at lag 3 day, 11.81%(95%CI: 4.55%, 19.07%) at lag 5 day, 12.34%(95%CI: 3.89%, 20.78%) at lag 0-2 day and 10.56%(95%CI: 0.61%, 20.52%) at lag 0-3 day, respectively.Conclusion: Personal PM2.5 exposure had positive effects on FeNO and blood inflammation markers(IL-1?), but a negative effect on lung function. These effects were delayed in a certain degree.