title: Triggering of myocardial infarction by increased ambient fine particle concentration: Effect modification by source direction.
abstract: BACKGROUND
  Previously, we reported a 18% increased odds of ST-elevation myocardial infarction (STEMI) associated with each 7.1 µg/m(3) increase in PM2.5 concentration in the hour prior to MI onset. We found no association with non-ST elevation myocardial infarction (NSTEMI). We examined if this association was modified by PM2.5 source direction.
  
  
  METHODS
  We used the NOAA HYbrid Single-Particle Lagrangian Trajectory (HYSPLIT) model to calculate each hourly air mass location for the 24 hours before each case or control time period in our previous PM2.5/STEMI case-crossover analysis. Using these data on patients with STEMI (n=338), hourly PM2.5 concentrations, and case-crossover methods, we evaluated whether our PM2.5/STEMI association was modified by whether the air mass passed through each of the 8 cardinal wind direction sectors in the previous 24h.
  
  
  RESULTS
  When the air mass passed through the West-Southwest direction (WSW) any time in the past 24h, the odds of STEMI associated with each 7.1µg/m(3) increase in PM2.5 concentration in the previous hour (OR=1.27; 95% CI=1.08, 1.22) was statistically significantly (p=0.01) greater than the relative odds of STEMI associated with increased PM2.5 concentration when the wind arrived from any other direction (OR=0.99; 95% CI=0.80, 1.22). We found no other effect modification by any other source direction. Further, relative odds estimates were largest when the time spent in the WSW was 8-16 h, compared to ≤7 h or 17-24 h, suggesting that particles arising from sources in this direction were more potent in triggering STEMIs.
  
  
  CONCLUSIONS
  Since relative odds estimates were higher when the air mass passed through the WSW octant in the past 24h, there may be specific components of the ambient aerosol that are more potent in triggering STEMIs. This direction is associated with substantial emissions from coal-fired power plants and other industrial sources of the Ohio River Valley, many of which are undergoing modifications to reduce their emissions.
authors.affiliation: Center for Air Resources Engineering and Science, Clarkson University, Potsdam, NY, USA. Electronic address: phopke@clarkson.edu.
authors.forename: Philip K
authors.initials: PK
authors.lastname: Hopke
authors.affiliation: Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
authors.forename: Cathleen
authors.initials: C
authors.lastname: Kane
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Utell
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Chalupa
authors.affiliation: Center for Air Resources Engineering and Science, Clarkson University, Potsdam, NY, USA.
authors.forename: Pramod
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Division of Cardiology, Department of Medicine, University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Frederick
authors.initials: F
authors.lastname: Ling
authors.affiliation: Central Utah Clinic, St George, Utah, USA.
authors.forename: Blake
authors.initials: B
authors.lastname: Gardner
authors.affiliation: Department of Public Health Sciences, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA.
authors.forename: David Q
authors.initials: DQ
authors.lastname: Rich
mesh_terms: D000336:Aerosols; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000209:etiology*; D009518:New York / Q000453:epidemiology; D016017:Odds Ratio; D010316:Particle Size; D052638:Particulate Matter / Q000009:adverse effects / Q000032:analysis*; D012307:Risk Factors; D014919:Wind
chemical_list: D000336:Aerosols; D000393:Air Pollutants; D052638:Particulate Matter
keywords: Back trajectory; Myocardial infarction; PM2.5; Secondary pollutants