title: Indoor air pollution from biomass combustion and acute respiratory infections in Kenya: an exposure-response study.
abstract: BACKGROUND
  Acute respiratory infections (ARI) are the leading cause of the global burden of disease and have been causally linked with exposure to pollutants from domestic biomass fuels in less-developed countries. We used longitudinal health data coupled with detailed monitoring of personal exposure from more than 2 years of field measurements in rural Kenya to estimate the exposure-response relation for particulates smaller than 10 mm in diameter (PM(10)) generated from biomass combustion.
  
  
  METHODS
  55 randomly-selected households (including 93 infants and children, 229 individuals between 5 and 49 years of age, and 23 aged 50 or older) in central Kenya were followed up for more than 2 years. Longitudinal data on ARI and acute lower respiratory infections (ALRI) were recorded at weekly clinical examinations. Exposure to PM(10) was monitored by measurement of PM(10) emission concentration and time-activity budgets.
  
  
  RESULTS
  With the best estimate of the exposure-response relation, we found that ARI and ALRI are increasing concave functions of average daily exposure to PM(10), with the rate of increase declining for exposures above about 1000-2000 mg/m(3). After we had included high-intensity exposure episodes, sex was no longer a significant predictor of ARI and ALRI.
  
  
  CONCLUSIONS
  The benefits of reduced exposure to PM(10) are larger for average exposure less than about 1000-2000 mg/m(3). Our findings have important consequences for international public-health policies, energy and combustion research, and technology transfer efforts that affect more than 2 billion people worldwide.
authors.affiliation: Center for Risk Management, Resources for the Future, Washington, DC, USA. ezzati@rff.org
authors.forename: M
authors.initials: M
authors.lastname: Ezzati
authors.forename: D
authors.initials: D
authors.lastname: Kammen
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects / Q000032:analysis*; D016902:Air Pollution, Indoor / Q000009:adverse effects / Q000032:analysis* / Q000706:statistics & numerical data; D018533:Biomass; D002648:Child; D002675:Child, Preschool; D003296:Cooking; D003906:Developing Countries; D004736:Energy-Generating Resources; D004784:Environmental Monitoring / Q000379:methods*; D062665:Epidemiological Monitoring; D005260:Female; D006361:Heating; D006798:Housing; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007630:Kenya / Q000453:epidemiology; D016018:Least-Squares Analysis; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D011634:Public Health; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000209:etiology*
chemical_list: D000393:Air Pollutants