title: Exposure to air pollution near a steel plant and effects on cardiovascular physiology: a randomized crossover study.
abstract: BACKGROUND
  Iron and steel industry is an important source of air pollution emissions. Few studies have investigated cardiovascular effects of air pollutants emitted from steel plants.
  
  
  OBJECTIVE
  We examined the influence of outdoor air pollution in the vicinity of a steel plant on cardiovascular physiology in Sault Ste. Marie, Canada.
  
  
  METHODS
  Sixty-one healthy, non-smoking subjects (females/males=33/28, median age 22 years) spent 5 consecutive 8-hour days outdoors in a residential area neighbouring a steel plant, or on a college campus approximately 5 kilometres away from the plant, and then crossed over to the other site with a 9-day washout. Mid day, subjects underwent daily 30-minute moderate intensity exercise. Blood pressure (BP) and pulse rate were determined daily and post exercise at both sites. Flow-mediated vasodilation (FMD) was determined at the site near the plant. Air pollution was monitored at both sites. Mixed-effects regressions were run for statistical associations, adjusting for weather variables.
  
  
  RESULTS
  Concentrations of ultrafine particles, sulphur dioxide (SO2), nitrogen dioxide (NO2) and carbon monoxide (CO) were 50-100% higher at the site near the plant than at the college site, with minor differences in temperature, humidity, and concentrations of particulate matter ≤2.5 μm in size (PM2.5) and ozone (O3). Resting pulse rate [mean (95% confidence interval)] was moderately higher near the steel plant [+1.53 bpm (0.31, 2.78)] than at the college site, male subjects having the highest pulse rate elevation [+2.77 bpm (0.78, 4.76)]. Resting systolic and diastolic BP and pulse pressure, and post-exercise BP and pulse rate were not significantly different between two sites. Interquartile range concentrations of SO2 (2.9 ppb), NO2 (5.0 ppb) and CO (0.2 ppm) were associated with increased pulse rate [0.19 bpm (-0.00, 0.38), 0.86 bpm (0.03, 1.68), and 0.11 bpm (0.00, 0.22), respectively], ultrafine particles (10,256 count/cm(3)) associated with increased pulse pressure [0.85 mmHg (0.23, 1.48)], and NO2 and CO inversely associated with FMD [-0.14% (-0.31, 0.02), -0.02% (-0.03, -0.00), respectively]. SO2 during exercise was associated with increased pulse rate [0.26 bpm (0.01, 0.51)].
  
  
  CONCLUSIONS
  Air quality in residential areas near steel plants may influence cardiovascular physiology.
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada. Electronic address: ling.liu@hc-sc.gc.ca.
authors.forename: Ling
authors.initials: L
authors.lastname: Liu
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Lisa Marie
authors.initials: LM
authors.lastname: Kauri
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Mamun
authors.initials: M
authors.lastname: Mahmud
authors.affiliation: Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: Weichenthal
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Sabit
authors.initials: S
authors.lastname: Cakmak
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Robin
authors.initials: R
authors.lastname: Shutt
authors.affiliation: Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Hongyu
authors.initials: H
authors.lastname: You
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Errol
authors.initials: E
authors.lastname: Thomson
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Renaud
authors.initials: R
authors.lastname: Vincent
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Premkumari
authors.initials: P
authors.lastname: Kumarathasan
authors.affiliation: The NORDIK Institute, Algoma University, Sault Ste. Marie, Ontario, Canada.
authors.forename: Gayle
authors.initials: G
authors.lastname: Broad
authors.affiliation: Environmental Health Science and Research Bureau, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada.
authors.forename: Robert
authors.initials: R
authors.lastname: Dales
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D001794:Blood Pressure / Q000187:drug effects; D002170:Canada; D002248:Carbon Monoxide / Q000009:adverse effects* / Q000032:analysis; D018592:Cross-Over Studies; D004781:Environmental Exposure / Q000009:adverse effects* / Q000032:analysis; D015444:Exercise / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007221:Industry; D007501:Iron; D008297:Male; D009585:Nitrogen Dioxide / Q000009:adverse effects* / Q000032:analysis; D010126:Ozone; D052638:Particulate Matter / Q000009:adverse effects / Q000032:analysis; D013232:Steel; D013458:Sulfur Dioxide / Q000009:adverse effects* / Q000032:analysis; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D013458:Sulfur Dioxide; D013232:Steel; D010126:Ozone; D002248:Carbon Monoxide; D007501:Iron; D009585:Nitrogen Dioxide
keywords: 95% CI; 95% confidence interval; Air pollution; BAD; BP; Blood pressure; CO; DBP; FMD; Flow-mediated vasodilation; IQR; Iron and steel industry; NO(2); O(3); PM(2.5); PP; PR; Pulse rate; SBP; SO(2); UFP; basal brachial artery diameter; beats per minute; blood pressure; bpm; carbon monoxide; diastolic blood pressure; flow-mediated vasodilation; interquartile range; nitrogen dioxide; ozone; particulate matter at aerodynamic diameter ≤2.5μm; pulse pressure; pulse rate; sulphur dioxide; systolic blood pressure; ultrafine particles