Kirk Ullmann
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View article: Global Observations of Acetyl Peroxynitrate (PAN) in the Remote Troposphere
Global Observations of Acetyl Peroxynitrate (PAN) in the Remote Troposphere Open
We present global airborne observations of acetyl peroxynitrate (CH 3 C(O)OONO 2 , PAN) in the remote troposphere from the Atmospheric Tomography (ATom) campaign. These observations show that biomass burning is the dominant source of PAN i…
View article: Modeling actinic flux and photolysis frequencies in dense biomass burning plumes
Modeling actinic flux and photolysis frequencies in dense biomass burning plumes Open
Biomass burning (BB) affects air quality and climate by releasing large quantities of gaseous and particulate pollutants into the atmosphere. Photochemical processing during daylight transforms these emissions, influencing their overall en…
View article: Black Carbon Reflects Extremely Efficient Aerosol Wet Removal in Monsoonal Convective Transport
Black Carbon Reflects Extremely Efficient Aerosol Wet Removal in Monsoonal Convective Transport Open
Refractory black carbon (rBC) is a primary aerosol species, produced through incomplete combustion, that absorbs sunlight and contributes to positive radiative forcing. The overall climate effect of rBC depends on its spatial distribution …
View article: Modeling actinic flux and photolysis frequencies in dense biomass burning plumes
Modeling actinic flux and photolysis frequencies in dense biomass burning plumes Open
Biomass-burning (BB) affects air quality and climate by releasing large amounts of gaseous and particulate pollutants into the atmosphere. Photochemical processing during daylight transforms these emissions, influencing their overall envir…
View article: Using observed urban NO <sub> <i>x</i> </sub> sinks to constrain VOC reactivity and the ozone and radical budget in the Seoul Metropolitan Area
Using observed urban NO <sub> <i>x</i> </sub> sinks to constrain VOC reactivity and the ozone and radical budget in the Seoul Metropolitan Area Open
Ozone (O3) is an important secondary pollutant that impacts air quality and human health. Eastern Asia has high regional O3 background due to the numerous sources and increasing and rapid industrial growth, which also impacts the Seoul Met…
View article: Comment on egusphere-2024-596
Comment on egusphere-2024-596 Open
Abstract. Ozone (O3) is an important secondary pollutant that impacts air quality and human health. Eastern Asia has high regional O3 background due to the numerous sources and increasing and rapid industrial growth, which impacts the Seou…
View article: Comment on egusphere-2024-596
Comment on egusphere-2024-596 Open
Abstract. Ozone (O3) is an important secondary pollutant that impacts air quality and human health. Eastern Asia has high regional O3 background due to the numerous sources and increasing and rapid industrial growth, which impacts the Seou…
View article: Using observed urban NO <sub>x</sub> sinks to constrain VOC reactivity and the ozone and radical budget in the Seoul Metropolitan Area
Using observed urban NO <sub>x</sub> sinks to constrain VOC reactivity and the ozone and radical budget in the Seoul Metropolitan Area Open
Ozone (O3) is an important secondary pollutant that impacts air quality and human health. Eastern Asia has high regional O3 background due to the numerous sources and increasing and rapid industrial growth, which impacts the Seoul Metropol…
View article: Observations of cyanogen bromide (BrCN) in the global troposphere and their relation to polar surface O <sub>3</sub> destruction
Observations of cyanogen bromide (BrCN) in the global troposphere and their relation to polar surface O <sub>3</sub> destruction Open
Bromine activation (the production of Br in an elevated oxidation state) promotes ozone destruction and mercury removal in the global troposphere and commonly occurs in both springtime polar boundary layers, often accompanied by nearly com…
View article: Airborne Observations Constrain Heterogeneous Nitrogen and Halogen Chemistry on Tropospheric and Stratospheric Biomass Burning Aerosol
Airborne Observations Constrain Heterogeneous Nitrogen and Halogen Chemistry on Tropospheric and Stratospheric Biomass Burning Aerosol Open
Heterogeneous chemical cycles of pyrogenic nitrogen and halides influence tropospheric ozone and affect the stratosphere during extreme Pyrocumulonimbus (PyroCB) events. We report field‐derived N 2 O 5 uptake coefficients, γ (N 2 O 5 ), an…
View article: Airborne Observations Constrain Heterogeneous Nitrogen and Halogen Chemistry on Tropospheric and Stratospheric Biomass Burning Aerosol
Airborne Observations Constrain Heterogeneous Nitrogen and Halogen Chemistry on Tropospheric and Stratospheric Biomass Burning Aerosol Open
Heterogeneous chemical cycles of pyrogenic nitrogen and halides influence tropospheric ozone and affect the stratosphere during extreme pyrocumulonimbus (PyroCB) events. We report field-derived N2O5 uptake coefficients, γ(N2O5), and ClNO2 …
View article: An observation-based, reduced-form model for oxidation in the remote marine troposphere
An observation-based, reduced-form model for oxidation in the remote marine troposphere Open
The hydroxyl radical (OH) fuels atmospheric chemical cycling as the main sink for methane and a driver of the formation and loss of many air pollutants, but direct OH observations are sparse. We develop and evaluate an observation-based pr…
View article: Comment on egusphere-2023-860
Comment on egusphere-2023-860 Open
Abstract. Active bromine (e.g., Br2, BrCl, BrO, HOBr) promotes atmospheric ozone destruction and mercury removal. Here we report a previously unidentified participant in active-Br chemistry, cyanogen bromide (BrCN), measured during the NAS…
View article: Observations of cyanogen bromide (BrCN) in the global troposphere and their relation to polar surface O <sub>3</sub> destruction
Observations of cyanogen bromide (BrCN) in the global troposphere and their relation to polar surface O <sub>3</sub> destruction Open
Active bromine (e.g., Br2, BrCl, BrO, HOBr) promotes atmospheric ozone destruction and mercury removal. Here we report a previously unidentified participant in active-Br chemistry, cyanogen bromide (BrCN), measured during the NASA Atmosphe…
View article: Supplementary material to "Observations of cyanogen bromide (BrCN) in the global troposphere and their relation to polar surface O <sub>3</sub> destruction"
Supplementary material to "Observations of cyanogen bromide (BrCN) in the global troposphere and their relation to polar surface O <sub>3</sub> destruction" Open
Supplement to: BrCN in the global troposphere 1 Formation of BrCN from HOBr chemistryThe formation of XCN compounds from reactions of HCN/CN¯ in the condensed phase is well known, so deserves consideration in the context of the polar bound…
View article: External cycling of NOx promotes the oxidative capacity of the atmosphere
External cycling of NOx promotes the oxidative capacity of the atmosphere Open
External cycling routes regenerating NO x from its oxidative reservoir, NO z , might reshape the temporal–spatial distribution of NO x and consequently OH, the most important atmospheric oxidant. However, the kinetics and mechanisms of the…
View article: Understanding the climate impacts of the Asian Summer Monsoon with in-situ observations of aerosol microphysical properties in the upper troposphere and lower stratosphere
Understanding the climate impacts of the Asian Summer Monsoon with in-situ observations of aerosol microphysical properties in the upper troposphere and lower stratosphere Open
The Asian monsoon anticyclone transports aerosol and gas phase pollutants from the boundary layer to the upper troposphere and lower stratosphere, from whence they are transported out over the Western Pacific by eddy shedding. This signifi…
View article: Emission factors and evolution of SO <sub>2</sub> measured from biomass burning in wildfires and agricultural fires
Emission factors and evolution of SO <sub>2</sub> measured from biomass burning in wildfires and agricultural fires Open
Fires emit sufficient sulfur to affect local and regional air quality and climate. This study analyzes SO2 emission factors and variability in smoke plumes from US wildfires and agricultural fires, as well as their relationship to sulfate …
View article: Evaluating the Impact of Chemical Complexity and Horizontal Resolution on Tropospheric Ozone Over the Conterminous US With a Global Variable Resolution Chemistry Model
Evaluating the Impact of Chemical Complexity and Horizontal Resolution on Tropospheric Ozone Over the Conterminous US With a Global Variable Resolution Chemistry Model Open
A new configuration of the Community Earth System Model (CESM)/Community Atmosphere Model with full chemistry (CAM‐chem) supporting the capability of horizontal mesh refinement through the use of the spectral element (SE) dynamical core is…
View article: Comment on acp-2022-309
Comment on acp-2022-309 Open
Abstract. Fires emit sufficient sulfur to affect local and regional air quality and climate. This study analyzes SO2 emission factors and variability in smoke plumes from US wild and agricultural fires, and their relationship to sulfate an…
View article: Comment on acp-2022-309 Please check rate constant
Comment on acp-2022-309 Please check rate constant Open
Fires emit sufficient sulfur to affect local and regional air quality and climate. This study analyzes SO2 emission factors and variability in smoke plumes from US wild and agricultural fires, and their relationship to sulfate and hydroxym…