title: The Effect of Exposure to Low Levels of Chlorine Gas on the Pulmonary Function and Symptoms in a Chloralkali Unit.
abstract: BACKGROUND
  The present study was undertaken to ascertain whether (or not) long term occupational exposure to low (sub-TLV levels) atmospheric concentrations of chlorine gas was associated with any significant decrements in the parameters of pulmonary function and/or  increased prevalence of respiratory symptoms.
  
  
  METHODS
  In this retrospective cohort study that was performed in 2012, 54 workers of a local chloralkali unit and 38 non-exposed office staff were enrolled and compared. Atmospheric concentrations of chlorine gas were measured by numerous sampling with gas detector tubes. Data on respiratory symptoms were gathered using a standard questionnaire. Furthermore, spirometry test was performed for subjects both prior to and at the end of shift.
  
  
  RESULTS
  Mean atmospheric concentration of chlorine gas was 0.27 ±0.05 ppm that was lower than the existing TLV value for this toxic irritant gas. Symptoms of respiratory diseases were significantly more frequent among exposed subjects than in referent individuals. Additionally, mean values of most parameters of pulmonary function including FEV1 (P=0.031), FEV1/FVC ratio (P=0.003) and PEF (P=0.005) were significantly lower than their corresponding values for unexposed subjects. Additional cross shift decrements were also noted in some lung functional capacities, although changes were not statistically significant.
  
  
  CONCLUSIONS
  Exposure to sub-TLV levels of chlorine gas is associated with statistically significant decrements in the parameters of pulmonary function as well as increased prevalence of respiratory symptoms.
authors.affiliation: Research Center for Health Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Masoud
authors.initials: M
authors.lastname: Neghab
authors.affiliation: Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran. fatemehamiri1366@gmail.com.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Amiri
authors.affiliation: Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Esmaeel
authors.initials: E
authors.lastname: Soleimani
authors.affiliation: Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Seyed Younus
authors.initials: SY
authors.lastname: Hosseini
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002713:Chlorine / Q000032:analysis / Q000633:toxicity*; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D009784:Occupational Diseases / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D015995:Prevalence; D012129:Respiratory Function Tests; D012140:Respiratory Tract Diseases / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*; D012189:Retrospective Studies; D014797:Vital Capacity / Q000502:physiology
chemical_list: D002713:Chlorine
keywords: Chloralkali Plant; Chlorine; Respiratory Function Tests; Respiratory Symptoms