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1Dalhousie University, Department of Process Engineering and Applied Science, Halifax, Nova Scotia, Canada2Environment Canada, Dartmouth, Nova Scotia, Canada.3Dalhousie University, Department of Physics and Atmospheric Science, Halifax, Nova Scotia, Canada4Ocean University of China, College of Environmental Science and Engineering.5Environment Canada, Toronto, Ontario, Canada, 6Centre for Environmental Health Sciences, University of Montana7School of GeoSciences, The University of Edinburgh, Edinburgh, UK.8Department of Atmospheric Physics, Colorado State, Colorado, US.Corresponding author: mark.gibson@dal.ca, http://afrg.peas.dal.ca Mark D. Gibson1, James Kuchta1, Lucy Chisholm2, Tom Duck3, Jason Hopper1, Stephen Beauchamp2, David Waugh2, Gavin King1, Jeffrey Pierce3/8, Zhengyan Li4, Richard Leaitch5, Tony J. Ward6 Jan Haelssig1, Paul Palmer7 Quantifying the temporal variation of the boreal wildfire smoke contribution to PM2.5 in Halifax during the BORTAS-B mission using four receptor models.

ObjectiveQuantifying the temporal variation of the boreal wildfire smoke contribution to PM2.5 in Halifax during the BORTAS-B mission

Continuous PM2.5 (TSI DustTrak) nephelometerThermo Partisol 2025-dichot, 24-hr47 mm Teflon Filter PM2.5Magee AethalometerContinuous black carbon2x Thermo ChemCombs for PM2.5 Speciation @ 10L/min(1x 47 mm pre-fired quartz and 1x 47 mm nylon filter)

Environment Canadas, Aerodyne, Aerosol Chemical Speciation MonitorContinuousOrganic Matter

Four Receptor Models Used 1. Absolute Principal Component Scores

2. Pragmatic Mass Closure

3. USEPA Chemical Mass Balance

4. USEPA Positive Matrix Factorization

Details of models found > http://afrg.peas.dal.ca/publishing/

Absolute Principal Component Scores Model Results

Pragmatic Mass Closure Receptor Model Results

USEPA Chemical Mass Balance Receptor Model Results

USEPA Positive Matrix Factorization Receptor Model Results

R2= 0.84n = 45

Marine air flow resulted very low PM2.5-woodsmoke contributionsEnsemble of daily NOAA HYSPLIT air mass back trajectories during BORTAS

These woodsmoke spikes were associated with NE airflow that crossed New Foundland and Cape Breton, en route to HalifaxEnsemble of daily NOAA HYSPLIT air mass back trajectories during BORTAS

Ontario boreal forest fire woodsmoke event22 JulyOntario Forest Fire

FLEXPART 5-DAY Air Parcel Forward Trajectory Model 17 July to 22 July 2011Air parcel crosses large forest fire in Northern Ontario, eventually impacting Halifax, Nova Scotia

FLEXPART Model of the Ontario forest fire smoke concentration directly above Halifax 20 July to 22 July 2011USEPA PMF PM2.5 source apportionment during BORTAS-B

SummaryAPCS, PMC and CMB models can not predict total PM2.5 mass concentrations below 2.0 mg/m3

USEPA PMF model able to predict total PM2.5 below 2.0 mg/m3

The use of a woodsmoke chemical marker such as levoglucosan is critical when carrying out PM2.5 source apportionment studies of boreal forest wild fire smoke

USEPA PMF model was the best model for predicting the wildfire smoke (and other sources) contribution to PM2.5 in Halifax during BORTAS-B

Next Steps

Paper in prep

Dalhousie Ground Station Paper(all observations)AcknowledgementsProfessor Paul Palmer (BORTAS lead) University of Edinburgh, School of GeoSciences for funding project consumables via Philip Leverhulme Prize

Health Canada for the loan of the black carbon analyzer, DustTraks, ChemComb samplers and chemical analysis

Atmospheric Forensics Research Grouphttp://afrg.peas.dal.ca

Photo courtesy of James Kuchta