title: Air pollution from industrial swine operations and blood pressure of neighboring residents.
abstract: BACKGROUND
  Industrial swine operations emit odorant chemicals including ammonia, hydrogen sulfide (H2S), and volatile organic compounds. Malodor and pollutant concentrations have been associated with self-reported stress and altered mood in prior studies.
  
  
  OBJECTIVE
  We conducted a repeated-measures study of air pollution, stress, and blood pressure in neighbors of swine operations.
  
  
  METHODS
  For approximately 2 weeks, 101 nonsmoking adult volunteers living near industrial swine operations in 16 neighborhoods in eastern North Carolina sat outdoors for 10 min twice daily at preselected times. Afterward, they reported levels of hog odor on a 9-point scale and measured their blood pressure twice using an automated oscillometric device. During the same 2- to 3-week period, we measured ambient levels of H2S and PM10 at a central location in each neighborhood. Associations between systolic and diastolic blood pressure (SBP and DBP, respectively) and pollutant measures were estimated using fixed-effects (conditional) linear regression with adjustment for time of day.
  
  
  RESULTS
  PM10 showed little association with blood pressure. DBP [β (SE)] increased 0.23 (0.08) mmHg per unit of reported hog odor during the 10 min outdoors and 0.12 (0.08) mmHg per 1-ppb increase of H2S concentration in the same hour. SBP increased 0.10 (0.12) mmHg per odor unit and 0.29 (0.12) mmHg per 1-ppb increase of H2S in the same hour. Reported stress was strongly associated with BP; adjustment for stress reduced the odor-DBP association, but the H2S-SBP association changed little.
  
  
  CONCLUSIONS
  Like noise and other repetitive environmental stressors, malodors may be associated with acute blood pressure increases that could contribute to development of chronic hypertension.
authors.affiliation: Department of Epidemiology, University of North Carolina–Chapel Hill, Chapel Hill, North Carolina 27599-7400, USA. steve_wing@unc.edu
authors.forename: Steve
authors.initials: S
authors.lastname: Wing
authors.forename: Rachel Avery
authors.initials: RA
authors.lastname: Horton
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Rose
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D007220:Industrial Waste / Q000009:adverse effects*; D052638:Particulate Matter / Q000633:toxicity*; D013552:Swine
chemical_list: D000393:Air Pollutants; D007220:Industrial Waste; D052638:Particulate Matter