Personal exposure to black carbon among women in semi-rural Mozambique

摘要

Background: Sub-Saharan Africa has the highest prevalence of people using solid fuels for household energy, which can result in products of incomplete combustion that are damaging for health. Black carbon (BC) is a useful marker of combustion-related particles; however air quality data and temporal patterns of personal exposure to BC in sub-Saharan Africa are scarce. We characterized personal exposure to BC in women from a semi-rural area of southern Mozambique. Methods: A total of 204 non-smoking women were randomly selected from the demographic surveillance system of the Manhica Health Research Centre between 2014-15. We measured 24h personal exposure to BC using a portable MicroAeth worn in a waist pouch and ambient elemental carbon (EC, highly comparable to BC) with a centrally-located stationary monitor. We used a questionnaire to obtain information on socio-demographic, household characteristics, and cooking/lighting use. We used backward linear regression to identify predictors of log-transformed 24-h mean BC exposure. Results: After excluding participants with poor data quality, we analyzed data from 142 (70%) women with a mean age of 30 years. Participants were largely housekeepers (88%) who principally used firewood (85%) and kerosene (52%) for cooking and lighting, respectively. Mean personal BC was 3.69μg/m~3(SD ±2.04) and 24h mean ambient EC was 0.85μg/m~3(SD ±0.59). Cooking fuel used during sampling (firewood vs charcoal) and same-day ambient EC were the determinants of exposure that were kept in the model (p<0.005). Plots of BC for all participants combined revealed a peak between 6-7pm, suggesting the contribution of lighting sources since the last cooking episode was 3-5pm. Conclusions: This study provides temporal patterns of BC exposure and suggests the important contribution of lighting, in addition to cooking, sources to personal exposure to combustion particles in populations that lack access to clean household energy.