Evaluation of Halogen-Induced Ozone Depletions Near Salt Lake City

Wyndom Chace, ANYL 1st year, CU Boulder

"An unexpected halogen-rich plume, originating from an industrial plant on the western shore of the Great Salt Lake, was sampled on nine separate flights during the NOAA 2017 Utah Winter Fine Particulate Study (UWFPS). Tropospheric ozone depletions were also measured in the halogen plume, analogous to halogen-induced ozone degradation in other regions of the atmosphere such as the arctic troposphere and the stratosphere. This study sought to quantify the halogen flux from the industrial plant and to characterize the photochemical processes that result in tropospheric ozone depletions. The calculated Cl2 and HCl emission fluxes were consistent with the industrial plant’s reported EPA emissions inventory; the inventory does not report fluxes of Br2 and BrCl, which also had significant calculated fluxes. The observed ozone depletions were investigated using a semi-Lagrangian plume setup in a zero-dimensional atmospheric chemistry box model (F0AM). The box model was able to reproduce the magnitude of ozone depletion observed in the daytime January 26 plume (>35 ppbv below background levels) and confirmed that chlorine and bromine radicals, generated from the photolysis of halogen species emitted by the plant, were responsible for the observed ozone depletions. These results suggest that atypical levels of industrial halogen emissions may have significant impacts on local air quality, particularly relevant in the case of this industrial plant due to its close proximity to Salt Lake City."

and

An Investigation of Ozone Chemistry During KORUS-AQ Using Observations and Modeling

Lindsey Anderson, ANYL 1st year, CU Boulder

"Ground-level ozone is a toxic air pollutant that is created from reactions of nitrogen oxides (NOx = NO + NO2) and volatile organic compounds (VOCs) in the presence of sunlight. The production of ozone is a nonlinear function of its precursors, which complicates emission regulations that target ozone reduction. In this study, ozone chemistry in Seoul, South Korea was investigated using flight observations from the Korea United States Air Quality (KORUS-AQ) field study. Measurements near the city center are characteristic of a highly polluted urban region with high levels of NOx concentration, while measurements to the southwest exhibit high levels of VOC concentration from chemical production facility emissions. The ozone production regime (NOx-limited vs. VOC-limited) in the Seoul Metropolitan Area (SMA) was determined to be VOC-limited, meaning reductions in the concentration of reactive VOCs would lead to a decrease in ozone production. Possible emission reduction regulations were then modeled to understand how they would impact ozone formation in the SMA. It was determined that emission regulations targeting ozone reduction in the SMA should include reductions in both NOx and reactive VOCs because NOx reduction alone would lead to an increase in ozone formation."

This week is in-person, join us in the ESOC Reading Room, Ekeley S230.

ESOC Coffee Hour occurs weekly from 9-10am MT on Wednesdays. For Fall 2021 we will be meeting on alternate weeks in person and on Zoom. Please email Claire Waugh (waughc@colorado.edu) for information.

ESOC researchers, post-docs and graduate students gather for conversation and to discuss research. Occasional guest speakers are invited to give short presentations on topics of interest.

Bringing Real-World Chemical Complexity to the Laboratory – Secondary Organic Aerosol Formation from Plant Emissions Increases Particle Viscosity and Alters Composition

Prof. Celia Faiola, Univ. of California-Irvine

"Climate change is influencing ecosystem health and plant biogeography. This affects the composition and spatiotemporal distribution of biogenic volatile organic compounds (BVOCs) across Earth’s surface. Perturbations to the types of compounds emitted could have significant impacts on secondary organic aerosol (SOA) production, but the chemistry of many of these compounds (including complex mixtures of these compounds) have not been studied comprehensively in a controlled laboratory environment. This presentation will summarize laboratory studies investigating SOA formation from complex mixtures of real plant emissions representing different plant emission types. Unexpected effects on aerosol chemistry, composition, and properties attributed to the presence of oxygenated monoterpenes and acyclic terpenes in the BVOC mixture were observed. Oxygenated monoterpenes (i.e. camphor and eucalyptol) that dominate emissions from sage and sagebrush produce SOA with more highly oxygenated molecules than SOA formed from more traditionally-studied terpenes. Acyclic terpenes (i.e. myrcene and farnesene) that are often associated with plant stress, reduce SOA yields and promote fragmentation reactions while increasing the viscosity of the resulting SOA. Aerosol chemistry of these compounds could become increasingly important with the expansion of drought-tolerant sage scrub and elevated frequency of plant stress conditions."

This week is remote, join us on Zoom.

ESOC Coffee Hour occurs weekly from 9-10am MT on Wednesdays. For Fall 2021 we will be meeting on alternate weeks in person and on Zoom. Please email Claire Waugh (waughc@colorado.edu) for information.

ESOC researchers, post-docs and graduate students gather for conversation and to discuss research. Occasional guest speakers are invited to give short presentations on topics of interest.

Join us Nov 11 at 1:30pm to learn about how to strengthen your interview skills at a seminar led by folks from CU Career Services. Whether you are interested in a career in academia, industry, or beyond, this seminar will help you learn how to 'sell' a prospective employer on the benefits you can bring to the company or institution. This seminar is virtual- so cozy up with a cup of tea this afternoon. You can find the recording for this event below!

Please join the CMC for their monthly meeting. Join by Google Meet or phone:  (US) +1 470-625-2129 (PIN: 494046379).

Evaluating TROPOMI CO Column Observations Using CU AirSOF During BB-FLUX

Jake Rowe, ANYL MS Defense, Volkamer group

"The Biomass Burning Fluxes of Trace Gases and Aerosols (BB-FLUX) field campaign was carried out during the summer of 2018 with the primary goal of quantifying emission fluxes of trace gases by mass balance of actual wildfires. To characterize these fluxes, the University of Colorado Airborne Solar Occultation Flux (CU AirSOF) instrument was flown below biomass burning plumes to measure vertical trace gas columns, such as carbon monoxide (CO, with the first overtone fit from 4214 - 4254 cm-1), along the direct solar beam. The TROPOspheric Monitoring Instrument (TROPOMI) provides measurements of trace-gas maps in the Ultraviolet-Visible (UV-Vis.) and shortwave-IR (SWIR) spectral regimes (e.g. CO from 4277 - 4303 cm-1). A subset of flights during BB-FLUX were dedicated to position the aircraft below smoke plumes while the satellite measures the same scene aloft.

Radiative transfer simulations were conducted to estimate the effect of aerosol multiple scattering in smoke plumes, which is not routinely accounted for in TROPOMI CO retrievals at short-wave infrared wavelengths. Aerosol multiple scattering recovers sensitivity losses in the absence of surface albedo (by up to 80%), but the loss is greatly reduced (5-10%) if surface albedo exceeds 10%. The difference in the temporal and spatial scales, and measurement geometries sampled from the aircraft and satellite are actively addressed by 1) focusing on near coincident case studies, 2) comparing spatial integrals of CO differential vertical column densities (dVCDs) across plumes, and 3) using the FLEXible PARTicle (FLEXPART) dispersion model to correct for different sampling times. CU AirSOF revealed variations in CO dVCD integrals on the order of 24% (up to 37%) over 30 mins (consecutive transect measurements) that characterize changes in emissions on the satellite sub-pixel scale. TROPOMI CO is found to be systematically higher relative to the aircraft by +26% for the operational product (+23% scientific product) without FLEXPART correction; such high-bias is reduced to +8.7% (+5.8%) upon adding the FLEXPART correction. The small but systematic high-bias in TROPOMI CO is most likely due to unaccounted aerosol multiple scattering, atmospheric variability, or a combination thereof."

This week is in-person, join us in the ESOC Reading Room, Ekeley S230.

ESOC Coffee Hour occurs weekly from 9-10am MT on Wednesdays. For Fall 2021 we will be meeting on alternate weeks in person and on Zoom. Please email Claire Waugh (waughc@colorado.edu) for information.

ESOC researchers, post-docs and graduate students gather for conversation and to discuss research. Occasional guest speakers are invited to give short presentations on topics of interest.

Summer 2021 was a year of extreme weather events in the Intermountain West. Drought conditions that were building since 2019 covered vast areas of the region with extreme and exceptional drought. A very strong North American Monsoon, especially in Utah and western Colorado broke rainfall records and caused flash flooding. Heavy monsoonal rainfall on the burn scars from the 2020 Cameron Peak and Grizzly Gulch Fires in Colorado caused the tragic loss of life and destruction of parts of Interstate 70 through Glenwood Canyon. Massive wildfires burning in California and Oregon significantly impacted regional air quality for much of the summer. Extreme weather events during 2021 exemplified the concept of compound natural hazards, where one natural hazard event causes a cascading series of natural hazards.

Nov 18, 2021 11:00 AM in Mountain Time (US and Canada)

Register here: https://cuboulder.zoom.us/webinar/register/WN_qwPkQxAWRxazMCwKTxbvpA