A5030348831- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Atmospheric and Environmental Gas Dynamics
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Fire effects on ecosystems
- Vehicle emissions and performance
- Indoor Air Quality and Microbial Exposure
- Oil Spill Detection and Mitigation
- Toxic Organic Pollutants Impact
- Advanced Aircraft Design and Technologies
- Gas Dynamics and Kinetic Theory
- Various Chemistry Research Topics
- nanoparticles nucleation surface interactions
- Meteorological Phenomena and Simulations
- Advanced Chemical Sensor Technologies
- Lightning and Electromagnetic Phenomena
- Analytical Chemistry and Sensors
- Analytical Chemistry and Chromatography
- Water Quality Monitoring and Analysis
- Ocean Acidification Effects and Responses
- Allergic Rhinitis and Sensitization
- Fire dynamics and safety research
- Aeolian processes and effects
University of Colorado Boulder
2016-2025
Colgate University
2018-2025
Cooperative Institute for Research in Environmental Sciences
2016-2025
NOAA Earth System Research Laboratory
2012-2024
National Oceanic and Atmospheric Administration
2011-2020
NOAA Chemical Sciences Laboratory
2014
Science Research Laboratory
2014
University of California, Berkeley
2006-2013
Planetary Science Institute
2007
California Institute of Technology
2007
Abstract Particulate brown carbon (BrC) in the atmosphere absorbs light at subvisible wavelengths and has poorly constrained but potentially large climate forcing impacts. BrC from biomass burning virtually unknown lifecycle atmospheric stability. Here, emitted intense wildfires was measured plumes transported over 2 days two main fires, during 2013 NASA SEAC4RS mission. Concurrent measurements of organic aerosol (OA) black (BC) mass concentration, BC coating thickness, absorption Ångström...
We use observations from two aircraft during the ICARTT campaign over eastern United States and North Atlantic summer 2004, interpreted with a global 3‐D model of tropospheric chemistry (GEOS‐Chem) to test current understanding regional sources, chemical evolution, export NO x . The boundary layer data provide top‐down verification 50% decrease in power plant industry emissions between 1999 2004. Observed concentrations at 8–12 km altitude were 0.55 ± 0.36 ppbv, much larger than previous...
Abstract We use a global chemical transport model (GEOS‐Chem) to interpret aircraft curtain observations of black carbon (BC) aerosol over the Pacific from 85°N 67°S during 2009–2011 HIAPER (High‐Performance Instrumented Airborne Platform for Environmental Research) Pole‐to‐Pole Observations (HIPPO) campaigns. Observed concentrations are very low, implying much more efficient scavenging than is usually implemented in models. Our simulation with source 6.5 Tg −1 and mean tropospheric lifetime...
Abstract. We use an ensemble of surface (EPA CSN, IMPROVE, SEARCH, AERONET), aircraft (SEAC4RS), and satellite (MODIS, MISR) observations over the southeast US during summer–fall 2013 to better understand aerosol sources in region relationship between particulate matter (PM) optical depth (AOD). The GEOS-Chem global chemical transport model (CTM) with 25 × km2 resolution North America is used as a common platform interpret measurements different variables made at times locations. Sulfate...
Abstract. We determine enhancement ratios for NOx, PAN, and other NOy species from boreal biomass burning using aircraft data obtained during the ARCTAS-B campaign examine impact of these emissions on tropospheric ozone in Arctic. find an initial emission factor NOx 1.06 g NO per kg dry matter (DM) burned, much lower than previous observations plumes, also one third value recommended extratropical fires. Our analysis provides first observational confirmation rapid PAN formation a smoke...
Abstract. Atmospheric black carbon (BC) is a leading climate warming agent, yet uncertainties on the global direct radiative forcing (DRF) remain large. Here we expand model simulation (GEOS-Chem) of BC to include absorption enhancement associated with coating and separately treat both aging physical properties fossil-fuel biomass-burning BC. In addition develop brown (BrC) from secondary (aromatic) primary (biomass burning biofuel) sources. The mean lifetime in this (4.4 days) substantially...
Detection of bioaerosols, or primary biological aerosol particles (PBAPs), has become increasingly important for a wide variety research communities and scientific questions. In particular, real-time (RT) techniques autonomous, online detection characterization PBAP properties in both outdoor indoor environments are becoming more commonplace have opened avenues research. With advances technology, however, come challenges to standardize practices so that results reliable comparable across...
Although laboratory experiments have shown that organic compounds in both gasoline fuel and diesel engine exhaust can form secondary aerosol (SOA), the fractional contribution from emissions to ambient SOA urban environments is poorly known. Here we use airborne ground‐based measurements of (OA) Los Angeles (LA) Basin, California made during May June 2010 assess amount formed emissions. Diesel LA Basin vary between weekdays weekends, with 54% lower on weekends. Despite this difference source...
Abstract. Organic aerosols (OA) that strongly absorb solar radiation in the near-UV are referred to as brown carbon (BrC). The sources, evolution, and optical properties of BrC remain highly uncertain contribute significantly uncertainty estimate global direct radiative effect (DRE) aerosols. Previous modeling studies DRE have been unable fully evaluate model performance due lack measurements absorption. In this study, we develop a simulation (GEOS-Chem) test it against absorption from two...
Abstract. Extensive airborne measurements of non-methane organic gases (NMOGs), methane, nitrogen oxides, reduced species, and aerosol emissions from US wild prescribed fires were conducted during the 2019 NOAA/NASA Fire Influence on Regional to Global Environments Air Quality campaign (FIREX-AQ). Here, we report atmospheric enhancement ratios (ERs) inferred emission factors (EFs) for compounds measured board NASA DC-8 research aircraft nine wildfires one fire, which encompass a range...
The formation of organic nitrates during the oxidation biogenic hydrocarbon isoprene can strongly affect boundary layer concentrations ozone and nitrogen oxides (NO x = NO + 2 ). We constrain uncertainties in chemistry these using chemical transport model simulations conjunction with observations over eastern United States from International Consortium for Atmospheric Research on Transport Transformation (ICARTT) field campaign summer 2004. best captures observed their correlation a 4% yield...
Organic compounds of intermediate volatility play an important role in the formation secondary organic aerosols.
A single particle soot photometer (SP2) uses an intense laser to heat individual aerosol particles of refractory black carbon (rBC) vaporization, causing them emit detectable amounts thermal radiation that are used quantify rBC mass. This approach is well suited for the detection majority mass loading in ambient atmosphere, which occurs primarily accumulation mode (∼ 1–300 fg-rBC/particle). In addition operator choices about instrument parameters, SP2 number and/or can be limited by physical...
A light-weight, low-cost optical particle spectrometer for measurements of aerosol number concentrations and size distributions has been designed, constructed, demonstrated. The is suitable use on small, unmanned aerial vehicles (UAVs) in balloon sondes. uses a 405 nm diode laser to count individual particles the range 140–3000 nm. compact data system combines custom electronics with single-board commercial computer. Power consumption 7W at 9–15 V. 3D printing technology was used...
Abstract Airborne observations of fluorescent aerosol were made aboard an airship during CloudLab, a series flights that took place in September and October 2013 covered wideband longitude across the continental U.S. between Florida California 28 37 N latitudes. Sampling occurred from near surface to 1000 m above ground. A Wideband Integrated Bioaerosol Sensor (WIBS‐4) measured average concentrations supermicron particles aloft (1 µm 10 µm), revealing number ranging 2.1 ± 0.8 8.7 2.2 × 4 −3...
Abstract. We present a new retrieval of tropospheric NO2 vertical column density from the Ozone Monitoring Instrument (OMI) based on high spatial and temporal resolution terrain profile inputs. compare our product, Berkeley High-Resolution (BEHR) with operational retrievals find that are biased (30 %) over remote areas low (8 urban regions. Additionally, we non-negligible impacts retrieved for pressure (±20 %), albedo (±40 (−75 %–+10 %). validate BEHR products using boundary layer aircraft...
The effect of anthropogenic black carbon (BC) aerosol on snow is enduring interest due to its consequences for climate forcing. Until now, too little attention has been focused BC's size in snow, an important parameter affecting BC light absorption snow. Here we present first observations this parameter, revealing that can be shifted larger sizes than are typically seen the atmosphere, part processes associated with removal from atmosphere. Mie theory analysis indicates a corresponding...
[1] Black carbon (BC) aerosol loadings were measured during the High-performance Instrumented Airborne Platform for Environmental Research Pole-to-Pole Observations (HIPPO) campaign above remote Pacific from 85°N to 67°S. Over 700 vertical profiles extending near surface max ∼14 km altitude obtained with a single-particle soot photometer between early 2009 and mid-2011. The data provides climatology of BC in regions that reveals gradients concentration reflecting global-scale transport...
We present an analysis of in situ NO 2 measurements from aircraft experiments between summer 2004 and spring 2006. The data are the INTEX‐A, PAVE, INTEX‐B campaigns constitute most comprehensive set tropospheric profiles to date. Profile shapes INTEX‐A PAVE found be qualitatively similar annual mean GEOS‐Chem model. Using campaign, we perform error‐weighted linear regressions compare Ozone Monitoring Instrument (OMI) columns near‐real‐time product (NRT) standard (SP) with integrated columns....
Atmospheric emissions of gas and particulate matter from a large ocean-going container vessel were sampled as it slowed switched high-sulfur to low-sulfur fuel transited into regulated coastal waters California. Reduction in emission factors (EFs) sulfur dioxide (SO2), matter, sulfate cloud condensation nuclei substantial (≥90%). EFs for organic decreased by 70%. Black carbon (BC) reduced 41%. When the measured reductions, brought about compliance with California quality regulation...
Abstract Emissions from 15 agricultural fires in the southeastern U.S. were measured NASA DC‐8 research aircraft during summer 2013 Studies of and Atmospheric Composition, Clouds Climate Coupling by Regional Surveys (SEAC 4 RS) campaign. This study reports a detailed set emission factors (EFs) for 25 trace gases 6 fine particle species. The chemical evolution primary emissions seven plumes was examined detail ~1.2 h. A Lagrangian plume cross‐section model used to simulate ozone (O 3 ),...
Abstract. Aircraft observations of meteorological, trace gas, and aerosol properties were made during May–September 2013 in the southeastern United States (US) under fair-weather, afternoon conditions with well-defined planetary boundary layer structure. Optical extinction at 532 nm was directly measured relative humidities (RHs) ∼ 15, 70, 90 % compared calculated from measurements composition size distribution using κ-Köhler approximation for hygroscopic growth. The enhancement hydrated...