title: Impact of air quality guidelines on COPD sufferers.
abstract: BACKGROUND
  COPD is one of the leading causes of morbidity and mortality in both high- and low-income countries and a major public health burden worldwide. While cigarette smoking remains the main cause of COPD, outdoor and indoor air pollution are important risk factors to its etiology. Although studies over the last 30 years helped reduce the values, it is not very clear if the current air quality guidelines are adequately protective for COPD sufferers.
  
  
  OBJECTIVE
  This systematic review was to summarize the up-to-date literature on the impact of air pollution on the COPD sufferers.
  
  
  METHODS
  PubMed and Google Scholar were utilized to search for articles related to our study's focus. Search terms included "COPD exacerbation", "air pollution", "air quality guidelines", "air quality standards", "COPD morbidity and mortality", "chronic bronchitis", and "air pollution control" separately and in combination. We focused on articles from 1990 to 2015. We also used articles prior to 1990 if they contained relevant information. We focused on articles written in English or with an English abstract. We also used the articles in the reference lists of the identified articles.
  
  
  RESULTS
  Both short-term and long-term exposures to outdoor air pollution around the world are associated with the mortality and morbidity of COPD sufferers even at levels below the current air quality guidelines. Biomass cooking in low-income countries was clearly associated with COPD morbidity in adult nonsmoking females.
  
  
  CONCLUSIONS
  There is a need to continue to improve the air quality guidelines. A range of intervention measures could be selected at different levels based on countries' socioeconomic conditions to reduce the air pollution exposure and COPD burden.
authors.affiliation: Department of Environmental and Occupational Health Sciences, School of Public Health, University of North Texas Health Science Center, Fort Worth, TX, USA.
authors.forename: Youcheng
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Endocrinology and Metabolism, Fourth Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang Province, People's Republic of China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Yan
authors.affiliation: Department of Environmental and Occupational Health Sciences, School of Public Health, University of North Texas Health Science Center, Fort Worth, TX, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Poh
authors.affiliation: Epidemiology, Human Genetics & Environmental Sciences, School of Public Health, The University of Texas Health Science Center at Houston, Houston, TX, USA.
authors.forename: Suyang
authors.initials: S
authors.lastname: Liu
authors.affiliation: Department of Environmental and Occupational Health Sciences, School of Public Health, University of North Texas Health Science Center, Fort Worth, TX, USA.
authors.forename: Emanehi
authors.initials: E
authors.lastname: Iyioriobhe
authors.affiliation: Department of Environmental and Occupational Health Sciences, School of Public Health, University of North Texas Health Science Center, Fort Worth, TX, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Sterling
mesh_terms: D000397:Air Pollution / Q000009:adverse effects / Q000517:prevention & control*; D017408:Guidelines as Topic; D006801:Humans; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*
keywords: COPD; air pollution; biomass; chronic bronchitis; intervention