Syndicate content

Addressing Household Air Pollution: A Case Study in Rural Madagascar

Susmita Dasgupta's picture

More than half the world’s population cooks with solid biomass fuels, such as wood, dung, charcoal or agricultural residues. Use of these fuels has been found to cause significant levels of respiratory infections, as well as trachea, bronchus, and lung cancers, ischemic heart disease, cerebrovascular disease, chronic obstructive pulmonary disease, and cataracts. The Global Burden of Disease Study 2010 found Household Air Pollution (HAP) from solid fuels to be the third leading cause of disease worldwide. Mitigation of HAP has a vital role for lowering health risks, particularly for women and children in developing countries where cooking with solid fuels is a common practice.

As incomes rise, the transition to modern energy sources will ultimately reduce HAP. During the transition, efforts to increase access to cleaner fuels, provision of improved stoves, and public information leading to improved ventilation and behavior change may significantly reduce exposure to household smoke. Design of HAP reduction strategies has been hindered, however, by a lack of data on air quality in households and the health benefits of potential mitigation measures.

To help fill these gaps, we (along with Hussain Samad) used new information from Madagascar on concentrations in household air of fine particles with diameter less than 2.5 microns (PM2.5) and carbon monoxide (CO), to analyze the effect of fuel type, stove type and ventilation on these sources of HAP.  Our analysis drew on a collaboration between the World Bank and a team led by Practical Action Consulting, including the University of Liverpool, Berkeley Air Monitoring, Eco-consult and Project GAIA, in close co-operation with Fondation TanyMeva, Meres Diligentes, and Agence de Jeunes pour la Developpment à Vatomandry. From 2009-210, the team monitored indoor air in a sample of households in two towns in Madagascar: Ambositra (located in the central highlands), and Vatomandry (located on the central east coast). In selecting households for air monitoring, the focus was on the two most predominant types of fuel, charcoal and wood. 

The Global Burden of Disease Study 2010 found that HAP is the second leading cause of disease in Madagascar, accounting for some 6.7% of the national burden of disease. More than 99 percent of households rely on solid biomass, such as charcoal, wood, and crop waste, as the main cooking fuel.  Since cooking with clean fuels is rare in Madagascar, after a baseline household survey and baseline monitoring of HAP, ethanol and ethanol stoves were distributed to a selected group of households. Locally produced ethanol is proposed by the Madagascar Ministry of Environment to help meet their goal of replacing 30 percent of fuelwood for cooking with cleaner fuels. Use of improved stoves is atypical, so improved charcoal and wood stoves were also distributed to another selected group of households to investigate their effectiveness as potential mitigation measures.

Concentrations of  PM2.5 and CO in kitchens were monitored three times during February-March 2009 (baseline), April 2010 (round 2), and July-August 2010 (round 3) using UCB Particle Monitors and GasBadge Pro Single Gas Monitors. Wherever air was monitored, average concentrations of both pollutants significantly exceeded World Health Organization guidelines for indoor exposure. 

We conducted a fixed-effect panel regression analysis to investigate the effects of various factors, including fuel (charcoal, wood, and ethanol), stove (traditional and improved), kitchen size, ventilation, building materials, and ambient environment on indoor air for a total of 338 households. Our findings strongly suggest that variations in cooking fuel, stove types and kitchen size produced large differences in HAP, with ethanol being significantly cleaner than other fuels judging by its effect on PM2.5 and CO.  Our findings also showed that a larger kitchen significantly improves the quality of household air.  As to the effectiveness of improved stoves as potential HAP mitigation measures, our findings are mixed. Compared with traditional charcoal stoves and traditional wood stoves, improved charcoal stoves were found to have no significant impact on air quality, but the improved wood stove with a chimney was effective in reducing concentrations of CO in the kitchen. Not surprisingly, measures to improve air circulation, especially via ventilation with outside air also provide significant benefits in reducing the concentration of CO.

These findings highlight a range of possible household adjustments that can significantly mitigate HAP exposure: first, switching to clean fuels (for example ethanol) is desirable; second, if cooking with clean fuels is not possible, use of an improved stove with a chimney can make a significant difference for concentrations of CO in households using wood fuel; finally, increased ventilation in cooking areas (and where possible a spacious kitchen) will yield a better household health environment.

Comments

Hello

We posted a link to this study on Indoor Air Pollution Updates, http://www.washplus.org

Submitted by Todd Moss on

Why don't your recommendations include the path that every single developed country has taken: Build a modern energy system using large scale generation?

Having consulted our energy sector colleagues, our response is the following: The commenter is quite right in indicating that developing access to electricity should be a priority in Madagascar. There is clear potential for increasing access to electricity in Madagascar by expanding the interconnected network. Also, in some rural localities, electrification through minigrids with mini or micro hydro is a viable option. However, electricity is not an economic solution for cooking at present, even for households with access to the grid (and the lifeline tariff, limited to 20 KWh per month, is designed to discourage economically inefficient use of electricity for cooking and other heating usages). In this context, the activities targeting cookstoves are complementary to electricity grid extension, in an obvious manner for rural households out of reach of the grid, but also for urban households. Cookstove programs can provide immediate benefits without paying the higher cost of electricity or waiting for costs to fall as the grid eventually is extended. The country also faces tremendous obstacles to achieve universal access to electricity, even if this were a preferred solution for providing cooking energy. A majority of households are poor and located in rural areas with low density of population, making grid extension costly. The reach of the grid remains limited today (barely above 15% of households connected). Even in the best case scenario, assuming that Madagascar manages to mobilize enough financial resources to aggressively expand the grid and generation capacity, a majority of households will remain out of reach for the electricity networks for several decades.

Submitted by Qian Di on

Epidemiology studies have proven causation between air pollution and cardiovascular disease. I am majored in public health and I was wondering whether it would be possible to access the benefits of this project in terms of public health. For example, one cohort study has quantified that the long-term hazard ratio (e.g. 10-year risk) of having cardiovascular events is 1.24 for every 10 microgram increase in PM2.5. In this project, improved charcoal stoves reduce indoor PM2.5 concentration by more than 300 microgram. I did some preliminary calculation: corresponding hazard ratio is about 16.49. That means, given 10 years, people living with traditional charcoal stoves are 16.49 times more likely to have cardiovascular events than people living with improved charcoal stoves! That could be a huge contribution to local public health.
However, this is just a preliminary estimation. Judging from standard public health approach or epidemiology method, aforementioned estimation is not accurate. If you are interested, you can contact me and I can find epidemiological study on indoor air pollution and make better estimation.

Submitted by Qian Di on

Epidemiology studies have proven causation between air pollution and cardiovascular disease. I am majored in public health and I was wondering whether it would be possible to access the benefits of this project in terms of public health. For example, one cohort study has quantified that the long-term hazard ratio (e.g. 10-year risk) of having cardiovascular events is 1.24 for every 10 microgram increase in PM2.5. In this project, improved charcoal stoves reduce indoor PM2.5 concentration by more than 300 microgram. I did some preliminary calculation: corresponding hazard ratio is about 16.49. That means, given 10 years, people living with traditional charcoal stoves are 16.49 times more likely to have cardiovascular events than people living with improved charcoal stoves! That could be a huge contribution to local public health.
However, this is just a preliminary estimation. Judging from standard public health approach or epidemiology method, aforementioned estimation is not accurate. If you are interested, you can contact me and I can find epidemiological study on indoor air pollution and make better estimation.

Add new comment