@article {78949, title = {Ubiquitous influence of wildfire emissions and secondary organic aerosol on summertime atmospheric aerosol in the forested Great Lakes region}, journal = {Atmospheric Chemistry and Physics}, volume = {18}, year = {2018}, month = {Jan-01-2018}, pages = {3701 - 3715}, abstract = {Long-range aerosol transport affects locations hundreds of kilometers from the point of emission, leading to distant particle sources influencing rural environments that have few major local sources. Source apportionment was conducted using real-time aerosol chemistry measurements made in July 2014 at the forested University of Michigan Biological Station near Pellston, Michigan, a site representative of the remote forested Great Lakes region. Size-resolved chemical composition of individual 0.5{\textendash}2.0 {\textmu}m particles was measured using an aerosol time-of-flight mass spectrometer (ATOFMS), and non-refractory aerosol mass less than 1 {\textmu}m (PM1) was measured with a high-resolution aerosol mass spectrometer (HR-AMS). The field site was influenced by air masses transporting Canadian wildfire emissions and urban pollution from Milwaukee and Chicago. During wildfireinfluenced periods, 0.5{\textendash}2.0 {\textmu}m particles were primarily aged biomass burning particles (88 \% by number). These particles were heavily coated with secondary organic aerosol (SOA) formed during transport, with organics (average O/C ratio of 0.8) contributing 89 \% of the PM1 mass. During urban-influenced periods, organic carbon, elemental carbon{\textendash} organic carbon, and aged biomass burning particles were identified, with inorganic secondary species (ammonium, sulfate, and nitrate) contributing 41 \% of the PM1 mass, indicative of atmospheric processing. With current models underpredicting organic carbon in this region and biomass burning being the largest combustion contributor to SOA by mass, these results highlight the importance for regional chemical transport models to accurately predict the impact of longrange transported particles on air quality in the upper Midwest, United States, particularly considering increasing intensity and frequency of Canadian wildfires.}, doi = {10.5194/acp-18-3701-201810.5194/acp-18-3701-2018-supplement}, url = {https://www.atmos-chem-phys.net/18/3701/2018/https://www.atmos-chem-phys.net/18/3701/2018/acp-18-3701-2018.pdfhttps://www.atmos-chem-phys.net/18/3701/2018/acp-18-3701-2018-supplement.pdf}, author = {Gunsch, Matthew J. and May, Nathaniel W. and Wen, Miao and Bottenus, Courtney L. H. and Gardner, Daniel J. and VanReken, Timothy M. and Bertman, Steven B. and Hopke, Philip K. and Ault, Andrew P. and Pratt, Kerri A.} } @article {70243, title = {Quantitative determination of biogenic volatile organic compounds in the atmosphere using proton-transfer reaction linear ion trap mass spectrometry}, journal = {Analytical Chemistry}, volume = {82}, year = {2010}, month = {10/2010}, pages = {7952 - 7957}, abstract = {Although oxidation of biogenic volatile organic compounds (BVOCs) plays an important role in tropospheric ozone and secondary organic aerosol production, significant uncertainties remain in our understanding of the impacts of BVOCs on ozone, aerosols, and climate. To quantify BVOCs, the proton-transfer reaction linear ion trap (PTR-LIT) mass spectrometer was previously developed. The PTR-LIT represents an improvement over more traditional techniques (including the proton-transfer reaction mass spectrometer), providing the capability to directly quantify and differentiate isomeric compounds by MS/MS analysis, with better time resolution and minimal sample handling, compared to gas chromatography techniques. Herein, we present results from the first field deployment of the PTR-LIT. During the Program for Research on Oxidants: Photochemistry, Emissions and Transport (PROPHET) summer 2008 study in northern Michigan, the PTR-LIT successfully quantified isoprene, total monoterpenes, and isomeric isoprene oxidation products methyl vinyl ketone and methacrolein at sub-parts per billion (nmol/mol) levels in a complex forest atmosphere. The utility of the fast time response of the PTR-LIT was shown by the measurement of rapid changes in isoprene, methyl vinyl ketone, and methacrolein, concurrent with changing ozone mole fractions. Overall, the PTR-LIT was shown to be a viable field instrument with the necessary sensitivity, selectivity, and time response to provide detailed measurements of BVOC mole fractions in complex atmospheric samples, at trace levels.}, keywords = {VOLATILE ORGANIC COMPOUNDS}, doi = {10.1021/ac1014244}, author = {Levi H. Mielke and Pratt, Kerri A. and Shepson, Paul B. and McLuckey, Scott A. and Wisthaler, Armin and Hansel, Armin} }