Air Pollution and Climate Forcing of the Charcoal Industry in Africa

Abstract

Demand for charcoal in Africa is growing rapidly, driven by urbanization and lack of access to electricity and other reliable and clean off-grid energy. Charcoal production and use, including plastic burning to initiate combustion, release large quantities of trace gases and particles that impact air quality and climate. In this work, past (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) trends in charcoal production and use in Africa are quantified and the dominant drivers identified to forecast the future (2030) of the industry. An inventory of current (2014) and future (2030) emissions from the charcoal supply chain in Africa has also been developed and implemented in the GEOS-Chem chemical transport model to quantify the contribution of charcoal to surface concentrations of PM2.5 and ozone, and direct radiative forcing due to aerosols and ozone. Charcoal production (and use) increased from 2000 to 2014 in Africa by a factor of 2. In 2014, the charcoal industry required 140-460 Tg fuelwood, depending on efficiency of combustion, to produce charcoal and 260 tonnes plastic for charcoal use to initiate combustion. The variability in wood required is due to variability in combustion efficiency of 9-30% that depends on kiln type and technology. The plastic use is an educated guess in the absence of statistics on its use and is most prevalent in low-income homes. A rough estimate of forest loss suggests that by 2030, 4.4-15 million hectares of forest will be lost in Africa due to charcoal production. By 2030, charcoal production will almost double which will drive a similar increase in emissions from the industry. Charcoal production makes a substantial contribution to CH4 emissions in Africa. These may outcompete CH4 emissions from open fires in West Africa by 2025. As expected, inefficient combustion emissions of CH4, NMVOCs, and CO are predominantly from charcoal production, whereas BC and NOx, signatures of efficient vTABLE OF CONTENTS LIST OF FIGURES .

Rapid rise in premature mortality due to anthropogenic air pollution in fast-growing tropical cities from 2005 to 2018

“…In nine African cities (Conakry, Niamey, N’Djamena, Addis Ababa, Nairobi, Kampala, Khartoum, Lubumbashi, and Lusaka), reactive NMVOCs decline at the same time as NO 2 increases, consistent with a shift to more efficient combustion sources, as is suggested by regional anthropogenic emission inventories ( 10 , 12 ). Rates of increase in reactive NMVOCs in cities in South Asia of 0.6 to 4.3% a −1 are less steep than trends in NO 2 (0.8 to 14.1% a −1 ).…”

“…S3). Regional bottom-up inventories also suggest that anthropogenic emissions already or will soon rival those from biomass burning ( 10 , 12 ).…”

“…The contribution from anthropogenic activity varies regionally and is greatest in tropical Asia, predominantly from residential combustion and industrial activity (7,9). Air pollution in tropical Africa is also influenced by natural sources (desert dust and biogenic emissions) as well as residential and commercial production and use of solid fuels (10)(11)(12). Seasonality in meteorology affects air quality, particularly in West Africa (13) and India (14), where southwesterly winds and heavy rainfall during the monsoon season disperse and wash away pollution and stagnant conditions during the dry season lead to its accumulation.…”

Isotopic signatures of methane emissions from tropical fires, agriculture and wetlands: the MOYA and ZWAMPS flights

“…Fires, urban and rural village emissions cause significant local and regional air pollution in Africa [24], but there have been very few measurements of δ 13 C CH 4 in methane from these sources. Routine annual grass and crop waste fires, and widespread charcoal burning [25] lead to over 40 000 premature deaths annually from biomass burning aerosols [26] and there is poor air quality over wide areas of Africa [11,27,28]. Enhanced trace gas and particle abundances have been measured over major cities: Accra, Lomé, Abijan and Cotonou [29][30][31], but there have been few airborne campaigns over heavily populated and intensively farmed rural regions in equatorial Africa.…”

Two-Tier Synergic Governance of Greenhouse Gas Emissions and Air Pollution in China’s Megacity, Shenzhen: Impact Evaluation and Policy Implication

“…Hence, the extension to nonenergy fields and the cost-effectiveness of two-tier synergic governance relative to traditional governance strategies need further exploration. Moreover, there exist complicated interactions between GHG and air pollutant emissions, microclimate, and air quality at an urban scale, 60,61 which has not been discussed in this study. How the synergic governance will affect urban microclimate and how microclimate change will interact with local air quality deserve further research.…”