title: Air pollution exposure and lung function in highly exposed subjects in Beijing, China: a repeated-measure study.
abstract: BACKGROUND
  Exposure to ambient particulate matter (PM) has been associated with reduced lung function. Elemental components of PM have been suggested to have critical roles in PM toxicity, but their contribution to respiratory effects remains under-investigated. We evaluated the effects of traffic-related PM(2.5) and its elemental components on lung function in two highly exposed groups of healthy adults in Beijing, China.
  
  
  METHODS
  The Beijing Truck Driver Air Pollution Study (BTDAS) included 60 truck drivers and 60 office workers evaluated in 2008. On two days separated by 1-2 weeks, we measured lung function at the end of the work day, personal PM(2.5), and nine elemental components of PM(2.5) during eight hours of work, i.e., elemental carbon (EC), potassium (K), sulfur (S), iron (Fe), silicon (Si), aluminum (Al), zinc (Zn), calcium (Ca), and titanium (Ti). We used covariate-adjusted mixed-effects models including PM(2.5) as a covariate to estimate the percentage change in lung function associated with an inter-quartile range (IQR) exposure increase.
  
  
  RESULTS
  The two groups had high and overlapping exposure distributions with mean personal PM(2.5) of 94.6 μg/m³ (IQR: 48.5-126.6) in office workers and 126.8 μg/m³ (IQR: 73.9-160.5) in truck drivers. The distributions of the nine elements showed group-specific profiles and generally higher levels in truck drivers. In all subjects combined, forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) did not significantly correlate with PM(2.5). However, FEV1 showed negative associations with concentrations of four elements: Si (-3.07%, 95% CI: -5.00; -1.11, IQR: 1.54), Al (-2.88%, 95% CI: -4.91; -0.81, IQR: 0.86), Ca (-1.86%, 95% CI: -2.95; -0.76, IQR: 1.33), and Ti (-2.58%, 95% CI: -4.44; -0.68, IQR: 0.03), and FVC showed negative associations with concentrations of three elements: Si (-3.23%, 95% CI: -5.61; -0.79), Al (-3.26%, 95% CI: -5.73; -0.72), and Ca (-1.86%, 95% CI: -3.23; -0.47). In stratified analysis, Si, Al, Ca, and Ti showed associations with lung function only among truck drivers, and no significant association among office workers.
  
  
  CONCLUSIONS
  Selected elemental components of PM(2.5) showed effects on lung function that were not found in analyses of particle levels alone.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. abaccare@hsph.harvard.edu.
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Baccarelli
authors.affiliation: Institute for Public Health and Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. y-zheng@northwestern.edu.
authors.forename: Yinan
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. xiao-zhang@northwestern.edu.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Safety Engineering, China Institute of Industrial Health, Beijing, China. changdou2004@sohu.com.
authors.forename: Dou
authors.initials: D
authors.lastname: Chang
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. lei.liu@northwestern.edu.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. wolf@northwestern.edu.
authors.forename: Katherine Rose
authors.initials: KR
authors.lastname: Wolf
authors.affiliation: Driskill Graduate Program in Life Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. zhou.zhang@northwestern.edu.
authors.forename: Zhou
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. jmccrack@hsph.harvard.edu.
authors.forename: John P
authors.initials: JP
authors.lastname: McCracken
authors.affiliation: Center for Health Studies, Universidad del Valle de Guatemala, Guatemala City, Guatemala. adiaz@ces.uvg.edu.gt.
authors.forename: Anaité
authors.initials: A
authors.lastname: Díaz
authors.affiliation: Center of Molecular and Genetic Epidemiology, Department of Clinical Sciences and Community Health, University of Milan and IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Italy. pieralberto.bertazzi@unimi.it.
authors.forename: Pier Alberto
authors.initials: PA
authors.lastname: Bertazzi
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. jschwrtz@hsph.harvard.edu.
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.affiliation: Department of Occupational and Environmental Health, Peking University Health Science Center, No. 38 Xueyuan Road, Haidian District, Beijing, 100191, China. shengw@bjmu.edu.cn.
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. cmkang@hsph.harvard.edu.
authors.forename: Choong-Min
authors.initials: CM
authors.lastname: Kang
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, MA, USA. petros@hsph.harvard.edu.
authors.forename: Petros
authors.initials: P
authors.lastname: Koutrakis
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. l-hou@northwestern.edu.|Robert H. Lurie Comprehensive Cancer Center, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA. l-hou@northwestern.edu.
authors.forename: Lifang
authors.initials: L
authors.lastname: Hou
mesh_terms: D000328:Adult; D000397:Air Pollution / Q000009:adverse effects*; D000535:Aluminum / Q000008:administration & dosage / Q000032:analysis / Q000633:toxicity; D002118:Calcium / Q000008:administration & dosage / Q000032:analysis / Q000633:toxicity; D002681:China; D018876:Environmental Illness / Q000139:chemically induced* / Q000503:physiopathology; D005260:Female; D005541:Forced Expiratory Volume / Q000187:drug effects; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects*; D008168:Lung / Q000187:drug effects* / Q000503:physiopathology; D008171:Lung Diseases / Q000139:chemically induced* / Q000503:physiopathology; D008297:Male; D009790:Occupations; D052638:Particulate Matter / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D020545:Respiratory Mucosa / Q000187:drug effects / Q000503:physiopathology; D012825:Silicon / Q000008:administration & dosage / Q000032:analysis / Q000633:toxicity; D013223:Statistics as Topic; D014025:Titanium / Q000008:administration & dosage / Q000032:analysis / Q000633:toxicity; D014504:Urban Health; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity; D014797:Vital Capacity / Q000187:drug effects
chemical_list: D052638:Particulate Matter; D001335:Vehicle Emissions; D000535:Aluminum; D014025:Titanium; D002118:Calcium; D012825:Silicon