Distribution of sources of household air pollution: a cross-sectional study in Cameroon

In targeted households, data was collected from head of households or representative after verbal/signed consent was obtained. Data was collected using a structured questionnaire administered in face to face interview by a trained surveyor. The questionnaire developed by the study team was pretested in households of one of the DHD health areas which was not selected and included in the study. For each household, data was collected on socio demographic information and characteristics of indoor sources of air pollution including fuels used for cooking. Primary cooking fuel was defined as the fuel used mainly by a household for cooking [4]. Secondary cooking fuel was defined as the fuel used as a backup for fuel-specific cooking activities by a household.

Resulting forms were verified daily to assess quality and completion. The resulting database was cleaned and analyzed by a statistician using Epi info version 7.2.2 software. Main analysis performed were proportions with a 95% confidence interval and tables were designed using MS-Excel 2013.

From this study, 90% of households used firewood and about 75% (630 households) of them exclusively used wood. Almost all households (98%) used wood to meet at least some of their cooking needs in rural HAs. Our results also reveal that 25% household have access to domestic gas for cooking, with a higher proportion in urban areas (55.6%) (Table 3). Figures 1 & 2 show the pictures of a charcoal and firewood fuel source, snapped in two separate households enrolled in the study. P-value less than 0.0005 as presented in Table 3 means the difference in proportion between urban and rural settings is statistically significant. It is important to note that no one was found to use an electric cooker or a micro wave.

Among the interviewed households, approximately 75% use more than one cooking fuel type (Table 4).

Nearly 60% of households choose their fuel type based on affordability and only 18% based on availability (Tables 5 and 6). Availability meant the presence of the fuel type in the surroundings of the household.

Figure 3 shows the frequency of both lone and multiple cooks in households. In 9 out of 10 households interviewed, women were reported to be the main cook. Children were involved in cooking in more than 60% of the households and men in only 7% of the households. It is to be emphasised that only the mothers in 270 (31.84%) and the children in 42(4.95%) were in charge of the cooking.

Food was cooked an average of one time (1.3 ± 0.5) per day in study households, with no variation between rural and urban areas. More than ¾ of households have been using their primary fuel type for more than five years (Table 7). Firewood has been used for the entire lifespan in almost all the households.

Results of this study reveal that firewood is the main biomass fuel type used in the Dschang Health District (90%) with a significant difference between the rural and urban settings. Other fuel types including domestic gas, kerosene, charcoal and sawdust, are also used in households with slight disparities between rural and urban, yet 75% of the population strictly rely on firewood for cooking. Approximately 75% of households of the DHD use more than one source of fuel however, this proportion was very low in the rural settings (11.3%). The results of this study are in accordance with the studies conducted so far in other areas of Cameroon, showing that households mostly rely on solid fuel (especially firewood) for cooking with a higher proportion in rural areas [17‐20]. Another published study conducted in another city of the same region (Bafoussam, which is the regional capital) had much lower reported solid fuel use (48%); the difference can be explained by the fact that it was conducted exclusively in an urban area with a smaller sample of household [21]. As also found in the same studies, other fuel types including domestic gas, kerosene, charcoal and sawdust are used but household access is still very limited (less than 5% at community level) for cooking; electricity is strictly used for no other purposes other than lighting. The use of clean fuels is still limited in both rural and urban areas of the DHD and therefore, the risk of developing HAP related diseases is permanently high for the people living in this area. Interventions targeting increasing population access to non-solid fuels (clean fuels) with consideration of rural and urban disparities should also be urgently implemented in this health district.

Interviewed head of households or representatives cited a number of factors influencing the choice of their cooking fuel type; affordability (59.5%) and availability (17.6%) were the main reasons. Other concerns were speed of cooking, ease of use, tradition, cleanliness and health and safety. This is in agreement with other studies carried out in different low-income areas of the world and other regions of Cameroon [17‐20]. The population preferred to use wood traditionally since they found it easy to get, that is either from their farms or comparatively cheaper (pay as you go) with respect to other sources of fuel such as gas since getting gas entails disbursing large amounts of money for an initial kit (gas burner, cylinder and accessories). Given the main reasons of choice of cooking fuels presented in this study, we believe that projects aiming to support households financial access to LPG fuels can increase reduce the proportion of households relying on unclean fuels.

This research study has shown that mothers and children were mostly those under this heavy load of HAP. Because of their customary involvement in cooking, especially women’s and children exposure is much higher than men’s as found in other studies [3, 22‐25]. Some children pay the prize of either been carried on the back during cooking hours or laid to sleep on kitchen beds during the cooking process.

These women and children have been exposed to IAP almost all their lives, since almost every HH (92.7 for Urban vs 98.4 for Rural) has been using firewood as their cooking fuel for more than 5 years and only 24% of households have used LPG as their source of cooking fuel for the same duration. This is confirmed by data from the National Demographic Health Survey which presented a prevalence of 28.1% of acute respiratory infections in children under five in 2014 [26]. Showing that the continuous exposure of the population to HAP is not leaving their health indifferent. As such, studies to evaluate their effective degree of HAP exposure and interventions to aiding the population to switch from solid fuels to cleaner sources of fuel is imperative.

This study was not without limit which however did not alter the credibility of the data presented. The principal limitation is information bias due to the fact that data collection procedures relied solely on the declaration of participants (heads of households or their representatives).