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Indoor Air Pollution

Indoor air pollution affects forecasts of under-5 mortality related to respiratory infection and adult (30+) mortality related to respiratory disease.  IFs uses the percentage of people using solid fuels as their primary source of energy (ENSOLFUEL) as a proxy for indoor air pollution.

The full model calculation is:

indoor eq 1

indoor eq 2

ENSOLFUEL = ratio of electricity use to total primary energy demand, in percentage

GDPPCP = gross domestic product per capita at purchasing power parity in thousand constant 2005 dollars

INFRAELECACC(national, that is, not urban or rural but total) = percent of total population with access to electricity in percentage

  • multiplicative shift factor: ENSOLFUELShift; never converges
  • multiplier: ensolfuelm
  • targeting parameters: ensolfuelsetar, ensolfueltrgtyr, ensolfuelsetar, ensolfuelseyrtar
  • hold switch: ensolflhldsw, fixes value of ENSOLFUEL at initial year value
  • cross-sectional data, GLM regression, R-squared = 0.81

The distal driver formulation for ENSOLFUEL uses the following formula, which relies also on EDYRSAG25 and average years of formal education for adults over 25.

indoor eq 3

indoor eq 4

We use a multiplicative shift factor to match initialization data in the first year, and keep it constant in our forecast. Following work done through the WHO Desai and others (2004), IFs adjusts in the full formulation (not the distal one) the percentage of population exposed to indoor smoke from solid fuels by a ventilation coefficient ( ensfvent ) that ranges from 0 to 1. A coefficient of 0 indicates no exposure to pollutants from solid fuel use, whereas a coefficient of 1 indicates full exposure: 

Recommended Ventilation Coefficients to use in Conjunction with Percentage of Population Exposed to Indoor Smoke from Solid Fuels
Country Ventilation Coefficient
Albania, Belarus, Bosnia & Herzegovina, Bulgaria, Croatia, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Macedonia, Moldova, Poland, Romania, Russia, Slovakia, Slovenia, Ukraine, Yugoslavia (Serbia and Montenegro) 0.20
China 0.25 for children; 0.50 for adults
All Others 1.0
From Desai and others (2004)

Since in the case of indoor air pollution there are only 2 categories–exposed or not exposed, in which case RR = 1 - the mortality effect can then be simplified to:

indoor eq 5

Where P is the percentage of population exposed to indoor smoke from solid fuel, adjusted for ventilation; and RR is the relative risk for the exposed population [1] .  The table below lists RRs used in IFs.  

Relative risk estimates for Mortality from Indoor Smoke from Solid Fuels
Health Outcome Groups Impacted Relative Risk
Respiratory Infections Children under 5 2.30 (1.90, 2.70)
Respiratory Diseases Females over 30 3.20 (2.30, 4.80)
Males over 30 1.80 (1.00, 3.20)
• From Desai and others (2004)
• 95% confidence intervals in parentheses



[1] More information is available on Dale’s documents: “Incorporating Indoor Air Pollution 9 October 2009.docx”, unpublished internal Pardee Center working note.