Determination of Emission Factors of Pollutants From Biomass Burning of African Fuels in Laboratory Measurements. Issue 20 (25th October 2021)

• Record Type: Journal Article
• Authors: Pokhrel, Rudra P.; Gordon, Janica; Fiddler, Marc N.; Bililign, Solomon
• Is Part Of: Journal of geophysical research. Volume 126:Issue 20(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-25
• Subjects: biomass burning -- emission factors -- air quality -- Sub‐ Sahran Africa; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2021JD034731
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Biomass burning (BB) is a major source of pollutants that impact local, regional, and global climate, air quality, and public health. However, the influence of burning conditions and fuel type on the emission factors of pollutants is still not well understood. Here, we present the results from a laboratory study of emission factors (EFs) of pollutants from six different sub‐Saharan African biomass fuels combusted under a wide range of burning conditions, ranging from smoldering to flaming. We found that particulate matter (PM) and carbon monoxide (CO) EFs (g (kg wood) −1 ) are highly sensitive to the burning conditions, with an order of magnitude variation between flaming and smoldering burning conditions. Nitric oxide (NO) EF shows a fuel type dependence, with higher NO EFs for fuels with larger nitrogen content. While CO is not generally a proxy for PM2.5 emissions, in this work a correlation was found between CO and PM emissions generated by combustion of seven wood fuels with moisture content (dry basis) <10% in a tube furnace and measured from a laboratory smog chamber with a temperature of ∼21–24°C and an RH below 5%. Unlike total PM, EFs of inorganic particle‐phase species do not show dependence on burning conditions. Finally, we showed that burning biomass fuels in a tube furnace would be a useful experimental approach to study BB emission under controlled burning conditions. Plain Language Summary: Biomass burning is a major source of pollutants that impact climate, air quality, and health. However, the influence of burning conditions and fuel type on the emission factors (EFs) of pollutants is not well understood. An EF relates the quantity of a pollutant released to the atmosphere for a given combustion process and is expressed as grams of emission per kilogram of fuel burned. EFs provide a means to estimate where and how much a pollutant is emitted from various sources so that air quality can be modeled. There are very limited measurements of EFs for African fuels. Here, we present the results from a laboratory study of emission factors of pollutants from six different sub‐Saharan African wooden biomass fuels combusted under a wide range of burning conditions, ranging from smoldering to flaming. We found that the EF of particulate matter and carbon monoxide are sensitive to the burning condition and the EF of nitric oxide depends on the nitrogen content of the fuel. A possible correlation between carbon monoxide emission and particulate matter emission is observed. A tube furnace was used to generate the BB emissions in this work, which offered an opportunity to conduct controlled burning in the laboratory. Key Points: Particulate matter and CO emission factors (EFs) are highly sensitive to the burning conditions of the fuel A correlation was found for CO and PM emissions generated by combustion of wood fuel in a tube furnace and measured in a laboratory chamber Fuel nitrogen content plays a significant role in the EF of NO