Characterization of Submicron Aerosols at the ASCENT Site in the Pristine North American Boreal Forest
JAMES CAMPBELL, Roya Bahreini, Ann M. Dillner, Armistead G. Russell, Nga Lee Ng, Jingqiu Mao, University of Alaska Fairbanks
Abstract Number: 430
Working Group: Coast to Coast Campaigns on Aerosols, Clouds, Chemistry, and Air Quality
Abstract
The boreal forests of the northern hemisphere represent the largest land biome on Earth, and their interactions with the atmosphere are essential to understanding future climate. Extensive work has been done in the European boreal forest to study forest-climate interactions, biogenic emissions, and aerosol chemistry. However, little work has been done in the North American boreal forest, despite differences in tree composition and VOC emissions. Since the summer of 2023, we deployed four instruments (ACSM, SMPS, Xact, AE33) at a remote site about 20 km south of Delta Junction, Alaska as part of the Atmospheric Science and Chemistry mEasurement NeTwork (ASCENT). This site is co-located with both NEON and AERONET networks. The ACSM shows that fine particle mass composition is dominated by organics, while the total mass is low year round except during wildfire periods. Extremely low concentrations of sulfate, nitrate, ammonium, and black carbon (all averaging less than 0.05 μg/m3) during non-wildfire periods suggest very little anthropogenic or biomass burning influence at the site. We further compare the ACSM measurements between our site and the Hyytiälä boreal forest site in central Finland, and show a weaker temperature dependence of organic aerosols at our site. Further investigation is underway to understand the differences and similarities on biogenic secondary organic aerosol formation between North American and European boreal forests.