AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Gas and Particle Phase Emissions from Residential Wood Combustion
DEEPIKA BHATTU, Peter Zotter, Giulia Stefenelli, Jun Zhou, Thomas Nussbaumer, Amelie Bertrand, Nicolas Marchand, Brice Temime-Roussel, Urs Baltensperger, Jay G. Slowik, Andre S.H. Prévôt, Imad EI Haddad, Josef Dommen, Paul Scherrer Institute
Abstract Number: 336 Working Group: Combustion
Abstract Residential wood combustion is one of the largest sources of both, gaseous pollutants and primary particulate emission, contributes a large portion (~80%) of secondary organic aerosol (SOA) mass, and has adverse health and environmental effects. Large variability and uncertainty in the emissions poses a challenge to the policy makers and environmental regulating authorities to control the emissions. We have examined primary emissions and the SOA formation potential of non-methane volatile organic compounds (NMVOCs) using an oxidation flow tube as a function of combustion device type (namely pellet boiler and stoves, log wood boiler and stoves, and industrial moving grate boiler), fuel type and load, and operating conditions. Particulate emissions were measured using a high resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), a scanning mobility particle sizer (SMPS), and an Aethalometer for black carbon , and non-methane gas-phase organic compounds with a proton transfer reaction mass spectrometer (PTR-MS) and a total hydrocarbons with a flame ionization detector (THC-FID), complemented by other conventional gas monitoring systems. The dependence of the intensity of gas-phase emissions on combustion conditions such as modified combustion efficiency, combustion temperature and excess air conditions was determined and linked to the observed chemical composition during combustion phases. NMVOCs were largely dominated by aldehydes, acids and alcohols with C< 6 for most of the combustion technologies. However, more poly-aromatic hydrocarbons (PAHs) and unsaturated hydrocarbons were observed during burn-out (char burning) phase compared to induction and flaming phase. An unsupervised clustering (bottom-up) approach along with the recursive partitioning (top-down) approach was used to deconvolute the effect of combustion devices, fuel type and their operating conditions on chemical composition. The aged OA: POA ratio in the log wood stoves was observed to be 6-27 times higher than in the pellet boiler depending on operating conditions. Further, we present the SOA formation potential of identified precursors during different combustion conditions to assess the overall contribution of residential wood burning to the total carbonaceous OA budget.