Biomass burning contribution to ambient air particulate levels at Navrongo in the Savannah zone of Ghana

Abstract

The concentrations of airborne particulate matter (PM) in Navrongo, a town in the Sahel Savannah Zone of Ghana, have been measured and the major sources have been identified. This area is prone to frequent particulate pollution episodes due to Harmattan dust and biomass burning, mostly from annual bushfires. The contribution of combustion emissions, particularly from biomass and fossil fuel, to ambient air particulate loadings was assessed. Sampling was conducted from February 2009 to February 2010 in Navrongo. Two Gent samplers were equipped to collect PM10 in two size fractions, coarse (PM10-2.5) and fine (PM2.5). Coarse particles are collected on a coated, 8-microm-pore Nuclepore filter. Fine particle samples were sampled with 47-mm-diameter Nuclepore and quartz filters. Elemental carbon (EC) and organic carbon (OC) concentrations were determined from the quartz filters using thermal optical reflectance (IMPROVE/TOR) methods. Elements were measured on the fine-particle Nuclepore filters using energy-dispersive x-ray fluorescence. The average PM2.5 mass concentration obtained at Navrongo was 32.3 microg/m. High carbonaceous concentrations were obtained from November to March, the period of Harmattan dust and severe bush fires. Total carbon was found to contribute approximately 40% of the PM2.5 particulate mass. Positive matrix factorization (PMF) suggested six major sources contributing to the PM2.5 mass. They are two stroke engines, gasoline emissions, soil dust, diesel emissions, biomass burning, and resuspended soil dust. Biomass combustion (16.0%) was identified as second most important source next to soil dust at Navrongo.

Kitchen Area Air Quality Measurements in Northern Ghana: Evaluating the Performance of a Low-Cost Particulate Sensor within a Household Energy Study

“…), season, urban/rural classification, and kitchen descriptions, which was ultimately reduced to the final model (Equation (6)). "Season" classification was consistent with current and past studies in this region [9,14,15,30,34,35,37,38,40,41,49,50] and "CoverageClass" is a variable used to classify kitchen descriptions to represent a wide range of kitchen area geometries and coverage types (e.g., roof with two walls, no roof with one wall). A breakdown of the "CoverageClass" by urban/rural samples is available in Figure S2 (Supplementary Materials).…”

“…One of our main research objectives utilizing the low-cost monitors was to characterize elevations in PM 2.5 concentrations above background levels to gain a better understanding of the sources of such deviations. Ambient concentrations of PM 2.5 in our study region, albeit relatively moderate as measured by others in this region [15], have potential significant overall health implications and would not be well captured by the low-cost monitors. Rather, our use of the low-cost monitors draws the much-needed attention to understanding the magnitudes and sources contributing most to increases in PM 2.5 concentrations known to have detrimental health effects, those from nearby sources.…”

“…These concentrations represent, on average, 71% and 61% of overall PM2.5 mass in rural and urban homes respectively, yet this percentage ranged from near 0% to 99% in both settings. Ambient air quality measurements made on the outskirts of Navrongo from 2010 of PM2.5 and PM10 allowed Ofosu and colleagues to perform source apportionment finding resuspended road and soil dust to be the leading contribution (52%) to total PM2.5 mass with biomass combustion as the second most important source (16%) [15]. It is important to note that these sample period exceedance percentages are quite conservative estimates of the percentage of days (24-h periods) exceeding the target levels.…”

Exposures to Carbon Monoxide in a Cookstove Intervention in Northern Ghana

“…(Supplementary Information, SI Section 7). The weak relationships are likely due to the variability in personal behaviors and the diversity of air pollution sources in the region [13,22]. The stronger relationship with OC may be due to the higher co-emission of CO than with EC in a typical biomass fire [23][24][25].…”

Effect of global atmospheric aerosol emission change on PM2.5-related health impacts

“…By contrast, China's rapid growth and urbanization have led to severe environmental pollution with concentrations beyond healthy air quality levels [51]. Similar to the cultural/traditional practices in India, sub-Saharan Africa owes its increased ambient PM 2.5 to savanna burning [52], with almost 30% of the tropical biomass being burned in the continent [53].…”