Ground-level air pollution changes during a boreal wildland mega-fire.
The 2011 Richardson wildland mega-fire in the Athabasca Oil Sands Region (AOSR) in northern Alberta, Canada had large effects on air quality. At a receptor site in the center of the AOSR ambient PM2.5, O3, NO, NO2, SO2, NH3, HONO, HNO3, NH4+and NO3-were measured during the April-August 2011 period. Concentrations of NH3, HNO3, NO2, SO2and O3were also monitored across the AOSR with passive samplers, providing monthly summer and bi-monthly winter average values in 2010, 2011 and 2012. During the fire, hourly PM2.5concentrations >450μgm-3were measured at the AMS 1 receptor site. The 24-h National Ambient Air Quality Standard (NAAQS) of 35μgm-3and the Canada Wide Standard (CWS) of 30μgm-3were exceeded on 13days in May and 7days in June. During the fire emission periods, sharp increases in NH3, HONO, HNO3, NH4+, NO3-and total inorganic reactive N concentrations occurred, all closely correlated with the PM2.5changes. There were large differences in the relative contribution of various N compounds to total inorganic N between the no-fire emission and fire emission periods. While in the absence of fires NO and NO2dominated, their relative contribution during the fires was ~2 fold smaller, mainly due to increased NH3, NH4+and NO3-. Concentrations of HONO and HNO3also greatly increased during the fires, but their contribution to the total inorganic N pool was relatively small. Elevated NH3and HNO3concentrations affected large areas of northern Alberta during the Richardson Fire. While NH3and HNO3concentrations were not at levels considered toxic to plants, these gases contributed significantly to atmospheric N deposition. Generally, no significant changes in O3and SO2concentrations were detected and their ambient concentrations were below levels harmful to human health or sensitive vegetation.
USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA. Electronic address: abytnerowicz@fs.fed.us.
Andrzej
A
Bytnerowicz
Wood Buffalo Environmental Association, #100-330 Thickwood Blvd., Fort McMurray, Alberta, T9K 1Y1, Canada.
Yu-Mei
YM
Hsu
Wood Buffalo Environmental Association, #100-330 Thickwood Blvd., Fort McMurray, Alberta, T9K 1Y1, Canada.
Kevin
K
Percy
Biosphere Solutions, Calgary, Alberta, T2N 1H7, Canada.
Allan
A
Legge
USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA. Electronic address: mfenn@fs.fed.us.
Mark E
ME
Fenn
USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA.
Susan
S
Schilling
Environmental Systems Research Institute, Redlands, CA 92373, USA.
Witold
W
Frączek
USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA.
Diane
D
Alexander
D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry; D000397:Air Pollution / Q000032:analysis*; D000416:Alberta; D000641:Ammonia / Q000032:analysis; D004784:Environmental Monitoring; D009566:Nitrates / Q000032:analysis; D017942:Nitric Acid / Q000032:analysis; D010126:Ozone / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry; D013458:Sulfur Dioxide / Q000032:analysis; D066188:Taiga; D000075923:Wildfires
D000393:Air Pollutants; D009566:Nitrates; D052638:Particulate Matter; D013458:Sulfur Dioxide; D017942:Nitric Acid; D010126:Ozone; D000641:Ammonia
Fine particulate matter; Ozone; Reactive nitrogenous species; Sulfate; Sulfur dioxide