Managing Chemical Complexity in Highly Parameterized Air Quality Models

Kelley Barsanti,
University of California, Riverside

"Tropospheric chemistry and air quality are strongly influenced by source emissions. In the western US, much attention has been on the air quality impacts of wildland fires; and more recently, changes in air quality associated with COVID-19 shelter-in-place restrictions. Fires emit high levels of trace gases, including semi-volatile and volatile organic compounds (S/VOCs); and primary (directly emitted) particulate matter (PM). During plume evolution, S/VOCs react to form ozone (O3) and secondary PM, thereby degrading air quality downwind. The amount of pollutants formed depends on fuel and fire characteristics, and plume dynamics and chemistry. Unfortunately, model predictions of O3 and PM from wildland fires are characterized by significant uncertainties. While there are a number of factors that lead to poor model predictions, research in our group has focused on three particular limitations: 1) incomplete identification and quantification of gaseous compounds emitted from fires that may serve as pollutant precursors; 2) incomplete understanding of the transformations of the precursors that lead to pollutant formation in smoke plumes; and 3) over-simplified representation of emissions and processes in current smoke and air quality models. Somewhat analogously, urban anthropogenic sources also emit large quantities of S/VOCs that react to form O3 and secondary PM. Changes in anthropogenic activity as result of COVID-19 restrictions have provided an opportunity to test recent hypotheses about the changing mix of VOCs emitted by urban anthropogenic sources and the relative importance of emerging anthropogenic sources for secondary pollutant formation; as well as to test our abilities to represent the chemistry of these sources in predictive models. In this talk, I will present an overview of our efforts in these areas: applying advanced analytical techniques to characterize the S/VOCs in smoke as a function of fuel species and component, and the S/VOCs over the LA Basin during COVID-19 shelter-in-place restrictions; using chemically-detailed box models to develop air quality model parameterizations; and developing a comprehensive emissions inventory that is broadly useful in air quality model applications."

Please join CIRES Director Waleed Abdalati for another CIRES Town Hall on Tuesday, March 2, 2021, for both CU Boulder and NOAA-based employees.

Join by Zoom: 

https://cuboulder.zoom.us/j/97783545542

ESOC virtual coffee hour occurs weekly from 9-10am on Wednesdays. We will be meeting remotely 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.

Letters of support for Outstanding Performance Awards are due today, March 5, 2021. Please refer to your nomination email for your customized link to submit.

Thank you!

The CMC

Aqueous Aerosols, Aerosol Chemistry, and the Chemical Disciplines

Prof. Murray Johnston,
University of Delaware

"Airborne particles strongly influence climate and human health. Understanding these impacts requires knowledge of chemical processes associated particle formation and growth, and draws upon fundamental principles in the chemical disciplines (analytical, physical, etc.). While these disciplines provide insight into aerosol chemistry, the reverse is also true: studying aerosols as opposed to bulk phases provides insight into disciplinary topics. This presentation will focus on the unique environment of aqueous aerosol particles, which can show very different reactivity from a bulk aqueous solution as well as from their dry particle counterparts. These differences have important implications for how particles grow in the atmosphere, and they help us better understand chemical measurements that rely on the formation of aerosol droplets."

ESOC virtual coffee hour occurs weekly from 9-10am on Wednesdays. We will be meeting remotely 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.

NC CASC Webinar Series: Our Changing Fire Regimes

Presented by: Jennifer Balch, NC CASC University Director, University of Colorado-Boulder 

Thursday, March 11, 2021, 11a-12p MST

Register in advance for this meeting:

https://cuboulder.zoom.us/meeting/register/tJAsc-2qrTktGNfU0IFzgBhh-dLJw...
After registering, you will receive a confirmation email with information on how to join the meeting.  

Abstract:
There are three ingredients needed for fire: fuel to burn, hot & dry conditions, and an ignition source. People are changing all three. The number of wildfires and the area burned has increased over the past several decades, in western U.S. forests by 1500%. Last year was one of the most expensive wildfire seasons ever in the U.S., costing over $16B. We need to learn to live with fire, again. But how? Ultimately, we need to burn better and build better.

About the Speaker:
Dr. Jennifer Balch is University Director of the North Central Climate Adaptation Science Center and Director of Earth Lab at the University of Colorado-Boulder. She is an Associate Professor in the Department of Geography. Dr. Balch’s research aims to understand the patterns and processes that underlie disturbance and ecosystem recovery, particularly how people are shifting fire regimes and the consequences. Her work spans from temperate regions to the tropics exploring how the major ingredients to fire are changing: climate, fuels, and ignitions. She has conducted research in the field of fire ecology for nearly twenty years, and has lit a few experimental burns to understand the consequences of altered fire regimes.

Past NC CASC Webinar Recordings:  https://nccasc.colorado.edu/webinars 

Dates for future NC CASC webinars:

April 8, 2021, 11a-12p MDT

May 13, 2021, 11a-12p MDT

June 10, 2021, 11a-12p MDT

July 8, 2021, 11a-12p MDT

August 12, 2021, 11a-12p MDT

September 9, 2021, 11a-12p MDT

October 14, 2021, 11a-12p MDT

November 11, 2021, 11a-12p MST

December 9, 2021, 11a-12p MST

ESOC virtual coffee hour occurs weekly from 9-10am on Wednesdays. We will be meeting remotely 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.

ESOC virtual coffee hour occurs weekly from 9-10am on Wednesdays. We will be meeting remotely 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.

Measurements of Volatile Organic Compounds during the COVID-19 Lockdown in Changzhou, China

Andrew Jensen,
ANYL 3rd year student, de Gouw group

"The COVID-19 outbreak in January 2020 prompted strict lockdowns, reduced human activity, and reduced emissions of associated pollutants. These reduced emissions have been estimated via remote and in-situ methods, but detailed measurements of volatile organic compounds (VOCs) are lacking. We measured VOCs in Changzhou, a Chinese city on the Yangtze River, during the local COVID-19 lockdowns from 8 January through 27 March, including periods of pre-lockdown, strict measures (level 1), and more relaxed measures accompanied by the return to work (level 2). VOCs were measured using a new, compact model of the Vocus proton-transfer-reaction time-of-flight mass spectrometer (Vocus Elf PTR-TOF-MS). We used positive matrix factorization to attribute VOCs to sources and employ an ensemble approach to determine uncertainties in the measured emission reductions. These uncertainties were further informed by satellite remote sensing and in-situ monitoring measurements of criteria pollutants, where we had measurements from previous years. Four factors of interest were resolved: textile industrial emissions (62±10%; average reduction during level 1 relative to pre-lockdown), pharmaceutical industrial emissions (40±20%), fresh traffic emissions (69±10%), and aged traffic emissions (73±14%). The quantified changes in the factors due to the lockdowns serve to constrain emission inventories and inform models, particularly for sectors where activity data are sparse, as the effects of lockdowns on air quality are explored."

ESOC virtual coffee hour occurs weekly from 9-10am on Wednesdays. We will be meeting remotely 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.