Air Pollution and Climate Forcing of the Charcoal Industry in Africa.

ABSTRACT

The demand for charcoal in Africa is growing rapidly, driven by urbanization and lack of access to electricity. Charcoal production and use, including plastic burning to initiate combustion, release large quantities of trace gases and particles that impact air quality and climate. Here, we develop an inventory of current (2014) and future (2030) emissions from the charcoal supply chain in Africa that we implement in the GEOS-Chem model to quantify the contribution of charcoal to surface concentrations of PM2.5 and ozone and direct radiative forcing due to aerosols and ozone. We estimate that the charcoal industry in 2014 required 140-460 Tg of biomass and 260 tonnes of plastic and that industry emissions could double by 2030, so that methane emissions from the charcoal industry could outcompete those from open fires by 2025. In 2014, the largest enhancements in PM2.5 (0.5-1.4 µg m-3) and ozone (0.4-0.7 ppbv) occur around the densely populated cities in East and West Africa. Cooling due to aerosols (-100 to -300 mW m-2) is concentrated over dense cities, whereas warming due to ozone is widespread, peaking at 4.2 mW m-2 over the Atlantic Ocean. These effects will worsen with ongoing dependence on this energy source, spurred by rapid urbanization and absence of viable cleaner alternatives.