title: Exposures to particulate matter and polycyclic aromatic hydrocarbons and oxidative stress in schoolchildren.
abstract: BACKGROUND
  Air pollution is known to contribute to respiratory and cardiovascular mortality and morbidity. Oxidative stress has been suggested as one of the main mechanisms for these effects on health.
  
  
  OBJECTIVE
  The aim of this study was to analyze the effects of exposure to particulate matter (PM) with aerodynamic diameters < or = 10 microm (PM10) and < or = 2.5 microm (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) on urinary malondialdehyde (MDA) levels in schoolchildren.
  
  
  METHODS
  The study population consisted of 120 schoolchildren. The survey and measurements were conducted in four cities--two in China (Ala Shan and Beijing) and two in Korea (Jeju and Seoul)--between 4 and 9 June 2007. We measured daily ambient levels of PM and their metal components at the selected schools during the study period. We also measured urinary 1-hydroxypyrene (1-OHP) and 2-naphthol, to assess PAH exposure, and MDA, to assess oxidative stress. Measurements were conducted once a day for 5 consecutive days. We constructed a linear mixed model after adjusting for individual variables to estimate the effects of PM and PAH on oxidative stress.
  
  
  RESULTS
  We found statistically significant increases in urinary MDA levels with ambient PM concentrations from the current day to the 2 previous days (p < 0.0001). Urinary 1-OHP level also showed a positive association with urinary MDA level, which was statistically significant with or without PM in the model (p < 0.05). Outdoor PM and urinary 1-OHP were synergistically associated with urinary MDA levels. Some metals bound to PM10 (aluminum, iron, strontium, magnesium, silicon, arsenic, barium, zinc, copper, and cadmium) and PM2.5 (magnesium, iron, strontium, arsenic, cadmium, zinc, aluminum, mercury, barium, and copper) also had significant associations with urinary MDA level.
  
  
  CONCLUSIONS
  Exposure to PM air pollution and PAHs was associated with oxidative stress in schoolchildren.
authors.affiliation: Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Sanghyuk
authors.initials: S
authors.lastname: Bae
authors.forename: Xiao-Chuan
authors.initials: XC
authors.lastname: Pan
authors.forename: Su-Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Kwangsik
authors.initials: K
authors.lastname: Park
authors.forename: Yoon-Hee
authors.initials: YH
authors.lastname: Kim
authors.forename: Ho
authors.initials: H
authors.lastname: Kim
authors.forename: Yun-Chul
authors.initials: YC
authors.lastname: Hong
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008315:Malondialdehyde / Q000652:urine; D018384:Oxidative Stress / Q000187:drug effects*; D052638:Particulate Matter / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D011084:Polycyclic Aromatic Hydrocarbons; D008315:Malondialdehyde