title: Does increased traffic flow around unconventional resource development activities represent the major respiratory hazard to neighboring communities?: knowns and unknowns.
abstract: The objective of this review is to demonstrate that the focus on air emissions causing respiratory effects and associated with gas development may be misplaced by attributing those exposures mainly to well pad activities.
  
  
  
  The most recent publications on the health effects of hydraulic fracturing operations seem to parallel findings from studies of diesel particulate exposure near roadways and the health effects associated with those exposures. It seems at least possible that some, if not all, of the respiratory effects associated with unconventional resource development may be traffic-related. Road traffic generated by hydraulic fracturing operations is one possible source of environmental impact whose significance has, until now, been largely neglected in the available literature with 4000 to 6000 vehicles visiting the well pad.
  
  
  
  Exposures from well pads diminish rapidly with distances of only a few kilometers but there is evidence showing disease risk multiple kilometers from well pads. This leaves open the possibility that the several thousand vehicle trips per well pad create traffic emissions over wide areas away from the pad. This alternative source of exposure has not previously been well studied but is being more seriously considered.
authors.affiliation: West Virginia University School of Public Health, One Medical Center Drive, Morgantown, West Virginia, USA.
authors.forename: Michael A
authors.initials: MA
authors.lastname: McCawley
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D004784:Environmental Monitoring; D006801:Humans; D000067071:Hydraulic Fracking; D052638:Particulate Matter / Q000009:adverse effects*; D012111:Residence Characteristics; D012140:Respiratory Tract Diseases / Q000209:etiology*; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions