title: Plasma nitrite is an indicator of acute changes in ambient air pollutant concentrations.
abstract: BACKGROUND
  Endothelial dysfunction has been suggested as a potential mechanism by which ambient air pollution may cause acute cardiovascular events. Recently, plasma nitrite has been developed as a marker of endothelial dysfunction.
  
  
  OBJECTIVE
  We examined the changes in plasma nitrite concentration associated with increases in ambient air pollutant concentrations in the previous 7 d.
  
  
  METHODS
  We linked up to three measurements of plasma nitrite concentrations obtained from 49 students to 24-h average concentrations of five criteria air pollutants [particle mass < 2.5 µm in aerodynamic diameter (PM(2.5)), carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), and ozone (O₃)] measured at two monitoring sites closest to Rutgers University campus (6-15 miles) in New Jersey during the years 2006-2009. We examined the change in plasma nitrite associated with each interquartile-range (IQR) increase in pollutant concentration in the previous 24 h and six preceding 24- h periods, using linear mixed models.
  
  
  RESULTS
  IQR increases in mean PM(2.5) (7.0 µg/m³) and CO (161.7 parts per billion) concentrations in the first 24 h before the plasma nitrite measurement were associated with increased plasma nitrite concentrations (PM(2.5): 15.5 nanomolar; 95% confidence interval (CI): 2.4, 28.5; CO: 15.6 nanomolar; 95% CI: 2.4, 28.9). Increased plasma nitrite associated with IQR increases in O₃ and SO₂ concentrations over longer lags were observed.
  
  
  CONCLUSIONS
  Rapid increases in plasma nitrite following exposure to ambient air pollutants support the hypothesis that ambient air pollution is associated with inducible nitric oxide synthase-mediated systemic inflammation in humans.
authors.affiliation: Department of Epidemiology, Rutgers School of Public Health , Piscataway, NJ , USA .
authors.forename: Sampada K
authors.initials: SK
authors.lastname: Gandhi
authors.forename: David Q
authors.initials: DQ
authors.lastname: Rich
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Ohman-Strickland
authors.forename: Howard M
authors.initials: HM
authors.lastname: Kipen
authors.forename: Andrew
authors.initials: A
authors.lastname: Gow
mesh_terms: D000293:Adolescent; D000328:Adult; D000397:Air Pollution / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D002248:Carbon Monoxide / Q000032:analysis / Q000633:toxicity*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000009:adverse effects*; D008297:Male; D008954:Models, Biological; D009515:New Jersey; D009573:Nitrites / Q000097:blood* / Q000378:metabolism; D010126:Ozone / Q000032:analysis / Q000633:toxicity; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D013458:Sulfur Dioxide / Q000032:analysis / Q000633:toxicity; D056647:Systemic Vasculitis / Q000097:blood / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology; D066007:Toxicokinetics; D014504:Urban Health; D055815:Young Adult
chemical_list: D015415:Biomarkers; D009573:Nitrites; D052638:Particulate Matter; D013458:Sulfur Dioxide; D010126:Ozone; D002248:Carbon Monoxide
keywords: Air pollution; ambient air pollutants; plasma nitrite concentration