Category Archives: Mt. Bachelor Observatory

Videos highlight research

Check out our new Videos page! There you’ll find videos that showcase the group’s research over the years. The page includes videos on airborne research in 2001 to current air quality research at Mt. Bachelor Observatory in Bend, Oregon.

Undergraduate researcher Shahbaz Qureshi recorded two videos about the group’s research in the summer of 2019. One shows the Jaffe team working at Mt. Bachelor Observatory, where they are setting up and maintaining research equipment. The second video focuses on a research trip to Boise, Idaho. During the summer of 2019, we measured volatile organic carbons, NOx, and other compounds at a site near Boise in order to understand the impact of forest fire emissions on the tropospheric photochemistry of ozone and aerosols at downwind sites. Qureshi has been conducting research with the Jaffe Group for the last year and graduated from the University of Washington Bothell in June 2020.

VIDEO: Jaffe team research trip to Boise, ID, Aug. 2019

VIDEO: Jaffe team working at Mt. Bachelor Observatory, Bend, OR, Sept. 2019

2 new papers explore methods for measuring biomass burning pollutants

Research by Jaffe Group postdoctoral scholars Dr. James Laing and Dr. Boggarapu Praphulla Chandra has resulted in two new peer-reviewed publications. Both papers examine methods used for measuring air pollutants from wildfires.

The first paper, “Comparison of filter-based absorption measurements of biomass burning aerosol and background aerosol at the Mt. Bachelor Observatory,” was recently published in Aerosol and Air Quality Research. The authors, Dr. James Laing, Dr. Daniel Jaffe, and Dr. Arthur Sedlacek, III, evaluated the upgraded aethalometer (AE33, Magee Scientific) and the new tricolor absorption photometer (TAP, Brechtel) to assess their effectiveness in measuring wildfire aerosol plumes. These instruments measure light-absorbing organic aerosols, which are emitted primarily in biomass burning. Both instruments were deployed at Mt. Bachelor Observatory (MBO) in central Oregon during the summer of 2016. Each instrument uses a similar methodology (“light extinction through an aerosol-laden filter”), but each has a unique set of corrections necessary to address filter-based bias and other issues. The coauthors found that when using the AE33 manufacturer’s recommended settings, correction factors that are larger than the manufacturer’s recommended factor are needed to calculate accurate absorption coefficients and equivalent black carbon.

Read the full paper.

In the second paper, coauthors Dr. Boggarapu Praphulla Chandra, Dr. Crystal McClure, JoAnne Mulligan, and Dr. Daniel Jaffe evaluated the use of dual-bed thermal desorption (TD) tubes with an auto-sampler to sample volatile organic compounds (VOCs). Their paper, “Optimization of a method for the detection of biomass-burning relevant VOCs in urban areas using thermal desorption gas chromatography mass spectrometry,” appeared in the journal Atmosphere in March. For this study, the authors utilized a portable, custom-made “suitcase” sampler, which they deployed in  Boise, ID, during the summer of 2019.

The sampler continuously collected samples of VOCs on the TD tubes for up to six days without the need for continuous on-site monitoring. The tubes were later transferred to the lab for analysis using thermal desorption gas chromatography mass spectrometry (TD-GC-MS) to detect VOCs.

Suitcase thermal desorption VOC auto-sampler 4-2020

(a) Internal view of the volatile organic compound (VOC) suitcase sampler; (b) Flow diagram of the VOC suitcase sampler; (c) Schematic diagram of the dual-bed TD tubes.

They found that “reactive and short-lived VOCs such as acetonitrile (a specific chemical tracer for biomass burning), acetone, n-pentane, isopentane, benzene, toluene, furan, acrolein, 2-butanone, 2,3-butanedione, methacrolein, 2,5- dimethylfuran, and furfural . . . can be quantified reproducibly with a total uncertainty of ≤30% between the collection and analysis, and with storage times of up to 15 days.”

Their research demonstrates the applicability of this flexible method for ambient VOC speciation and determining the influence of forest fire smoke. This sampling method offers a practical alternative for urban air quality monitoring sites because its portability does not require the installation of a complex and expensive instrument and its auto-sampling technique does not require continuous on-site monitoring.

Read the full paper.

Background ozone and implications for air quality management

In a new paper published in Elementa, Dan Jaffe and his coauthors look at background ozone in the US and how it influences whether states can meet air quality standards. Background ozone (O3) includes “contributions from natural and foreign sources of O3 that cannot be controlled by precursor emissions reductions solely within the US.” Understanding background O3 is necessary for air quality management overall and for states and municipalities to meet national air quality standards.

They examined over 100 published studies in order to assess what is the current knowledge about the distribution, trends, and sources of background ozone in the continental US. They found that “noncontrollable O3 sources, such as stratospheric intrusions or precursors from wildfires, can make significant contributions to O3 on some days, but it is challenging to quantify accurately these contributions.” In order to address this shortcoming, they recommend a more coordinated and focused approach to understanding background ozone in the US: improvements in the monitoring network, large-scale field experiments, more accurate and consistent chemical transport models, and more detailed observations of wildfires.

Read the paper here

2018 begins with 3 new group papers

The Jaffe Group has kicked off 2018 with 3 new publications.

  • Xi Gong, et al., Ozone in China: Spatial distribution and leading meteorological factors controlling O3 in 16 Chinese cities. Gong and her coauthors examined ozone (O3) concentrations in 16 Chinese cities and developed a statistical model to estimate the maximum daily 8-hour (MDA8) O3 during 2014–2016. They found that the Generalized Additive Model (GAM) captured 43-90% of daily O3 variations. They also identified the leading meteorological factors that affect O3 for each city. Read the full paper here.
Average 8-hour MDA8 (ug/m3) ozone concentrations for 16 Chinese cities, 2014-2016

Average maximum daily 8-hour (MDA8, ug/m3) ozone concentrations for 16 Chinese cities, 2014-2016.

  • Pao Baylon, et al., Impact of biomass burning plumes on photolysis rates and ozone formation at the Mount Bachelor Observatory. Baylon and his coauthors examined biomass burning (BB) events at Mt. Bachelor Observatory (MBO) during the summer of 2015. Biomass burning can emit large amounts of aerosols and gases into the atmosphere. These plumes contain compounds that react with sunlight to produce ozone, a health hazard to sensitive individuals. The photochemistry in BB plumes is poorly understand. Baylon and his coauthors addressed this knowledge gap by using MBO data to calculate ozone production rates and comparing these values with modeled values. Read the full paper here.
  • Lei Zhang, et al., A quantification method for peroxyacetyl nitrate (PAN) using gas chromatography (GC) with a non-radioactive pulsed discharge detector (PDD). Zhang and his coauthors developed a method for continuous peroxyacetyl nitrate (PAN) measurements using gas chromatography with a non-radioactive detector. PAN is a known precursor of ozone. Their method has high accuracy and is more readily deployable in field campaigns than the traditional gas chromatography method that utilizes a radioactive detector.  Read the full paper here.

2 New papers published in October

Two Jaffe Group members have published peer-reviewed papers in October. Well done to Xi Gong and Pao Baylon for their outstanding work!

Xi Gong and her coauthors used a statistical approach, the Generalized Additive Model,  to quantify ozone impacts from wildfires on 8 US cities. They showed that this approach can provide quantitative support for situations when large contributions from noncontrollable sources, such as wildfires, caused an exceedance of the EPA’s daily ozone standard.

Read the full paper here.

Pao Baylon and his coauthors looked at a Siberian biomass burning event in Spring 2015 that was observed at Mt. Bachelor Observatory and by satellite instruments, and also intercepted by a research aircraft. When the plume was in the eastern Pacific, it split into two plumes, one moving eastward toward MBO and the other moving northeast to Alaska and then south to the US Midwest. The second plume was observed by the aircraft in the Midwest. Baylon et al. found that the ozone production observed at MBO was higher than that of the aircraft plume. This was due to the plume at MBO being warmer and the aircraft plume being colder.

Read the full paper here.