title: Acute effects of fine particulate air pollution on cardiac arrhythmia: the APACR study.
abstract: BACKGROUND
  The mechanisms underlying the relationship between particulate matter (PM) air pollution and cardiac disease are not fully understood.
  
  
  OBJECTIVE
  We examined the effects and time course of exposure to fine PM [aerodynamic diameter ≤ 2.5 μm (PM(2.5))] on cardiac arrhythmia in 105 middle-age community-dwelling healthy nonsmokers in central Pennsylvania.
  
  
  METHODS
  The 24-hr beat-to-beat electrocardiography data were obtained using a high-resolution Holter system. After visually identifying and removing artifacts, we summarized the total number of premature ventricular contractions (PVCs) and premature atrial contractions (PACs) for each 30-min segment. A personal PM(2.5) nephelometer was used to measure individual-level real-time PM(2.5) exposures for 24 hr. We averaged these data to obtain 30-min average time-specific PM(2.5) exposures. Distributed lag models under the framework of negative binomial regression and generalized estimating equations were used to estimate the rate ratio between 10-μg/m³ increases in average PM(2.5) over 30-min intervals and ectopy counts.
  
  
  RESULTS
  The mean ± SD age of participants was 56 ± 8 years, with 40% male and 73% non-Hispanic white. The 30-min mean ± SD for PM(2.5) exposure was 13 ± 22 μg/m³, and PAC and PVC counts were 0.92 ± 4.94 and 1.22 ± 7.18. Increases of 10 μg/m³ in average PM(2.5) concentrations during the same 30 min or the previous 30 min were associated with 8% and 3% increases in average PVC counts, respectively. PM(2.5) was not significantly associated with PAC count.
  
  
  CONCLUSIONS
  PM(2.5) exposure within approximately 60 min was associated with increased PVC counts in healthy individuals.
authors.affiliation: Department of Public Health Sciences, the Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: He
authors.forename: Michele L
authors.initials: ML
authors.lastname: Shaffer
authors.forename: Sol
authors.initials: S
authors.lastname: Rodriguez-Colon
authors.forename: Jeff D
authors.initials: JD
authors.lastname: Yanosky
authors.forename: Edward
authors.initials: E
authors.lastname: Bixler
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Cascio
authors.forename: Duanping
authors.initials: D
authors.lastname: Liao
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000706:statistics & numerical data; D004562:Electrocardiography; D005260:Female; D006801:Humans; D019570:Inhalation Exposure; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000032:analysis*; D010414:Pennsylvania / Q000453:epidemiology; D013997:Time Factors; D018879:Ventricular Premature Complexes / Q000139:chemically induced* / Q000453:epidemiology
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter