Indoor Air Pollution from Household User of Solid Fuels – Chapter 18 of Comparative Quantification of Health Risks
This chapter summarizes the methodology used to assess the burden of
disease caused by indoor air pollution from household use of solid fuels.
Most research into and control of indoor air pollution worldwide has
focused on sources of particular concern in developed countries, such as
environmental tobacco smoke (ETS), volatile organic compounds from
furnishings and radon from soil. Although these pollutants have impacts
on health, little is known about their global distribution. Thus, we focus
solely on indoor smoke from household use of solid fuels, the most widespread
traditional source of indoor air pollution on a global scale.
In order to be consistent with the epidemiological literature, binary
classifications of household use of solid fuels (biomass and coal)
were used as a practical surrogate for actual exposure to indoor air
pollution. Specifically, household solid fuel use was estimated at the
national level using binary classifications of exposure to household fuel
use, i.e. solid fuel and non-solid fuel (gas, kerosene, electricity). We estimated
exposure to smoke from solid fuel by combining a number of
national surveys of household fuel use into a regression model that predicts
use according to independent, development-related variables, such
as income and urbanization. Although this method was necessary owing
to the current paucity of quantitative data on exposure, we acknowledge
that it overlooks the large variability of exposure within households
using solid fuels. As pollution emissions from the use of solid fuel may
not always indicate high exposures, we have adjusted exposure estimates
by a second term, the ventilation factor, which is based on qualitative
measures of ventilation.
Estimates of relative risk obtained from epidemiological studies
were combined in meta-analyses for three disease end-points for which
there is strong evidence of an association with use of solid fuels: acute
lower respiratory infections (ALRI) in children aged <5 years, chronic Chapter 18 Indoor air pollution from household use of solid fuels Kirk R. Smith, Sumi Mehta and Mirjam Maeusezahl-Feuz obstructive pulmonary disease (COPD) and lung cancer (estimates for lung cancer are only for use of coal). More than 1.6 million deaths and over 38.5 million disability-adjusted life years (DALYs) were attributable to indoor smoke from solid fuels in 2000. Cooking with solid fuels is thus responsible for a significant proportion, about 3%, of the global burden of disease. Although trends are highly uncertain, attributable risks are likely to be greater than avoidable risks. Several potentially important health outcomes, including tuberculosis, cardiovascular disease, and adverse pregnancy outcomes, were not included, owing to insufficient epidemiological evidence. In addition, there was insufficient evidence to assess the associated health effects for children aged 5–14 years. The burden of disease caused by use of solid fuel is thus likely to be underestimated.