title: Hemodynamic, autonomic, and vascular effects of exposure to coarse particulate matter air pollution from a rural location.
abstract: BACKGROUND
  Fine particulate matter (PM) air pollution is associated with numerous adverse health effects, including increased blood pressure (BP) and vascular dysfunction. Coarse PM substantially contributes to global air pollution, yet differs in characteristics from fine particles and is currently not regulated. However, the cardiovascular (CV) impacts of coarse PM exposure remain largely unknown.
  
  
  OBJECTIVE
  Our goal was to elucidate whether coarse PM, like fine PM, is itself capable of eliciting adverse CV responses.
  
  
  METHODS
  We performed a randomized double-blind crossover study in which 32 healthy adults (25.9 ± 6.6 years of age) were exposed to concentrated ambient coarse particles (CAP; 76.2 ± 51.5 μg/m(3)) in a rural location and filtered air (FA) for 2 hr. We measured CV outcomes during, immediately after, and 2 hr postexposures.
  
  
  RESULTS
  Both systolic (mean difference = 0.32 mmHg; 95% CI: 0.05, 0.58; p = 0.021) and diastolic BP (0.27 mmHg; 95% CI: 0.003, 0.53; p = 0.05) linearly increased per 10 min of exposure during the inhalation of coarse CAP when compared with changes during FA exposure. Heart rate was on average higher (4.1 bpm; 95% CI: 3.06, 5.12; p < 0.0001) and the ratio of low-to-high frequency heart rate variability increased (0.24; 95% CI: 0.07, 0.41; p = 0.007) during coarse particle versus FA exposure. Other outcomes (brachial flow-mediated dilatation, microvascular reactive hyperemia index, aortic hemodynamics, pulse wave velocity) were not differentially altered by the exposures.
  
  
  CONCLUSIONS
  Inhalation of coarse PM from a rural location is associated with a rapid elevation in BP and heart rate during exposure, likely due to the triggering of autonomic imbalance. These findings add mechanistic evidence supporting the biological plausibility that coarse particles could contribute to the triggering of acute CV events.
authors.affiliation: Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Robert D
authors.initials: RD
authors.lastname: Brook
authors.forename: Robert L
authors.initials: RL
authors.lastname: Bard
authors.forename: Masako
authors.initials: M
authors.lastname: Morishita
authors.forename: J Timothy
authors.initials: JT
authors.lastname: Dvonch
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.forename: Hui-Yu
authors.initials: HY
authors.lastname: Yang
authors.forename: Catherine
authors.initials: C
authors.lastname: Spino
authors.forename: Bhramar
authors.initials: B
authors.lastname: Mukherjee
authors.forename: Mariana J
authors.initials: MJ
authors.lastname: Kaplan
authors.forename: Srilakshmi
authors.initials: S
authors.lastname: Yalavarthi
authors.forename: Elif A
authors.initials: EA
authors.lastname: Oral
authors.forename: Nevin
authors.initials: N
authors.lastname: Ajluni
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Sun
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Brook
authors.forename: Jack
authors.initials: J
authors.lastname: Harkema
authors.forename: Sanjay
authors.initials: S
authors.lastname: Rajagopalan
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution / Q000706:statistics & numerical data*; D001794:Blood Pressure / Q000187:drug effects; D002320:Cardiovascular Physiological Phenomena / Q000187:drug effects*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D019570:Inhalation Exposure / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D052638:Particulate Matter / Q000633:toxicity*; D012424:Rural Population; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter