A cross-sectional study of household biomass fuel use among a periurban population in Malawi

Abstract

Rationale: The Global Burden of Disease Study suggests almost 3.5 million people die as a consequence of household air pollution every year. Respiratory diseases including chronic obstructive pulmonary disease and pneumonia in children are strongly associated with exposure to household air pollution. Smoke from burning biomass fuels for cooking, heating, and lighting is the main contributor to high household air pollution levels in low-income countries like Malawi. A greater understanding of biomass fuel use in Malawi should enable us to address household air pollution-associated communicable and noncommunicable diseases more effectively.

Objectives: To conduct a cross-sectional analysis of biomass fuel use and population demographics among adults in Blantyre, Malawi.

Methods: We used global positioning system-enabled personal digital assistants to collect data on location, age, sex, marital status, education, occupation, and fuel use. We describe these data and explore associations between demographics and reported fuel type.

Measurements and main results: A total of 16,079 adults participated (nine households refused); median age was 30 years, there was a similar distribution of men and women, 60% were married, and 62% received secondary school education. The most commonly reported occupation for men and women was "salaried employment" (40.7%) and "petty trader and marketing" (23.5%), respectively. Charcoal (81.5% of households), wood (36.5%), and electricity (29.1%) were the main fuels used at home. Only 3.9% of households used electricity exclusively. Lower educational and occupational attainment was associated with greater use of wood.

Conclusions: This large cross-sectional study has identified extensive use of biomass fuels in a typical sub-Saharan Africa periurban population in which women and people of lower socioeconomic status are disproportionately affected. Biomass fuel use is likely to be a major driver of existing communicable respiratory disease and the emerging noncommunicable disease (especially respiratory and cardiovascular) epidemic in this region. Our data will help inform the rationale for specific intervention studies and the development of appropriately targeted public health strategies to tackle this important and poverty-related global health problem.

Keywords: biomass fuel use; household air pollution; noncommunicable diseases.

Figure 1

World Health Organization energy ladder describing the relationship between different types of household fuels and prosperity. Adapted by permission from Reference 33.

Figure 2

World map showing the percentage of the population using solid fuels. Reproduced by permission from Myriad Editions (www.myriadeditions.com).

Figure 3

Map of Africa with Malawi highlighted in red.

Figure 4

An African woman using biomass fuel in an open fire in Malawi. Reproduced by permission from the photograph subject and photographer (K.M.).

Figure 5

Map of Blantyre city wards with Chilomoni ward in red and Queen Elizabeth Central Hospital as a yellow cross.

Figure 6

Image showing the global positioning system mapping of households, created using Google Earth Pro (licensed version).

Figure 7

Photograph showing collection of enumeration data using global positioning system–enabled personal digital assistant (SoMo Handheld Computer 650-E WM6.1 WW Eng EMEA). Reproduced by permission from all photograph subjects and the photographer (K.M.).

Figure 8

Consort diagram.

Figure 9

Age distribution of the study population. This frequency histogram describes the age distribution of the full study population (n = 16,079). Note the youngest participants were 17 years of age. Median age was 30 years (range, 17–102 yr).

Figure 10

Female and male occupations. This chart demonstrates occupations of the study population by sex for n = 16,076 (n = 3 missing data). “Other” includes any occupations that did not fit into the categories set out in the questionnaire.

Figure 11

Household fuel use of wood, charcoal, and electricity. This demonstrates the combinations of fuel use in 6,365 households that used wood, charcoal, or electricity (the three most common fuel types). Participants were allowed to select multiple fuel types. For clarity of presentation “electricity and wood” is not presented on the graph, as this group represented 0.3% of households (n = 22).

Figure 12

Fuel use according to education level. Exploration of distribution of types of fuel used by level of education achieved. Results suggest a relationship between lower level of education and greater use of wood and less use of electricity. The three most common fuel types are presented; “other” fuel types (lpg gas, paraffin, dung, and crop residue) were reported by less than 5% of each educational level group.

Figure 13

Fuel use according to age. Up to the age of 75 years, a trend was seen between increasing age and increased use of wood and decreased use of electricity. Data represent types of fuel used by 15,944 participants (135 individuals had no recorded fuel use). For clarity of presentation, the three most common fuel types are presented for individuals aged 17 to 95 years (excluding n = 1 respondent).