Criteria, Greenhouse Gas, and Hazardous Air Pollutant Emissions Factors from Residential Cordwood and Pellet Stoves Using an Integrated Duty Cycle Test Protocol
NORA TRAVISS, George Allen, Mahdi Ahmadi, NESCAUM
Abstract Number: 600
Working Group: Chemicals of Emerging Concern in Aerosol: Sources, Transformations, and Impacts
Abstract
Air pollution from residential wood heating (RWH) presents global challenges at the intersection of climate and public health. In the U.S., emissions factors (EFs) are a critical data input into the Environmental Protection Agency’s (EPA) National Emissions Inventory (NEI), underpinning air quality research, modeling, planning and decision-making functions at the national, state, local and Tribal levels. However, up-to-date EFs measured from currently available U.S. commercial stoves are an existing data gap. In this study, we used a novel stove testing protocol representing real-world operation called the Integrated Duty Cycle to determine EFs from six U.S. EPA-certified cordwood and pellet stoves, and one popular U.S. uncertified cordwood stove. We measured particulate matter (PM), other criteria pollutants (CO and NOx), nonmethane total hydrocarbons (NMTHCs), greenhouse gases (GHGs), and hazardous air pollutants (HAPs). Compared to the uncertified stove, the catalytic/hybrid cordwood and pellet stove EFs for PM, PAHs, and most HAPs were significantly lower (p <0.01). Noncatalytic and uncertified stove EFs exceeded 2020 NEI EFs for NMTHCs (16.8 and 32.7 g/kg wood burned, dry basis, respectively), and multiple HAPs such as formaldehyde (1.2 and 2.1 g/kg, respectively), benzene (0.4 and 1.5 g/kg, respectively) and many others. The noncatalytic stove PM EF (9.0 g/kg) exceeded the 2020 NEI EF as well. Applying the Pb EF from this study places RWH as the 4th highest source category of Pb in the 2020 NEI. RWH also emits 10 to 30 times more methane (CH4) compared to oil or natural gas residential heating, raising questions about substitution of wood as a climate neutral heating fuel. In summary, RWH appears to be an underestimated source of PM, methane, NMTHCs, Pb, and multiple HAPs, which has important implications for climate and public health policy in the U.S. and globally.