A5005051998- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Vehicle emissions and performance
- Atmospheric aerosols and clouds
- Fire effects on ecosystems
- Advanced Chemical Sensor Technologies
- Mass Spectrometry Techniques and Applications
- Spectroscopy and Laser Applications
- Water Quality Monitoring and Analysis
- Odor and Emission Control Technologies
- Oil Spill Detection and Mitigation
- Toxic Organic Pollutants Impact
- Fire dynamics and safety research
- Thermochemical Biomass Conversion Processes
- Analytical Chemistry and Chromatography
- Catalytic Processes in Materials Science
- Hydrocarbon exploration and reservoir analysis
- Indoor Air Quality and Microbial Exposure
- Marine and coastal ecosystems
- Plant responses to elevated CO2
- Advanced Aircraft Design and Technologies
- Industrial Gas Emission Control
National Oceanic and Atmospheric Administration
2016-2025
NOAA Chemical Sciences Laboratory
2008-2025
University of Colorado Boulder
2014-2024
Cooperative Institute for Research in Environmental Sciences
2014-2024
Washington University in St. Louis
2024
Goddard Space Flight Center
2024
Johannes Gutenberg University Mainz
2024
Earth Observing Laboratory
2024
NOAA Oceanic and Atmospheric Research
2023
NOAA Earth System Research Laboratory
2012-2021
Abstract Proton‐transfer‐reaction mass spectrometry (PTR‐MS) allows real‐time measurements of volatile organic compounds (VOCs) in air with a high sensitivity and fast time response. The use PTR‐MS atmospheric research has expanded rapidly recent years, much been learned about the instrument response specificity technique analysis from different regions atmosphere. This paper aims to review progress that made. theory operation is described be for operating conditions. More accurate...
The Mediterranean Intensive Oxidant Study, performed in the summer of 2001, uncovered air pollution layers from surface to an altitude 15 kilometers. In boundary layer, standards are exceeded throughout region, caused by West and East European north. Aerosol particles also reduce solar radiation penetration surface, which can suppress precipitation. middle troposphere, Asian a lesser extent North American is transported west. Additional east, monsoon upper crosses tropopause, pollutes lower...
An extensive set of volatile organic compounds (VOCs) and particulate matter (POM) was measured in polluted air during the New England Air Quality Study 2002. Using VOC ratios, photochemical age sampled masses estimated. This approach validated (1) by comparing observed rates at which VOCs were removed from atmosphere with expected OH oxidation, (2) emission ratios inferred data average composition urban air, (3) ability to describe increase an alkyl nitrate time terms chemical kinetics. A...
The formation of secondary organic aerosol (SOA) in an anthropogenic‐influenced region the southeastern United States is investigated by a comparison with urban plumes northeast. analysis based on measurements fine‐particle compounds soluble water (WSOC) as measure aerosol. Aircraft over large area northern Georgia, including Atlanta metropolitan region, and from New York City surrounding regions northeast show that WSOC are spatially correlated vehicle emission tracers (e.g., CO), yet...
In situ measurements of the mass, mixing state, and optical size individual black‐carbon (BC) particles in fine mode (90–600 nm) have been made fresh emissions from urban biomass burning sources with an airborne single‐particle soot photometer. Contrasts between two are significant consistent. Urban BC tends to smaller sizes, fewer coated particles, thinner coatings, less absorption per unit mass than biomass‐burning BC. This suggests that may a longer lifetime atmosphere different impact on...
We evaluate the performance of a new chemical ionization source called Vocus, consisting discharge reagent-ion and focusing ion–molecule reactor (FIMR) for use in proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF) measurements volatile organic compounds (VOCs) air. The reagent ion uses low-pressure discharge. FIMR consists glass tube with resistive coating, mounted inside radio frequency (RF) quadrupole. axial electric field is used to enhance collision energies limit...
We use a global three‐dimensional model simulation of atmospheric methanol to examine the consistency between observed concentrations and current understanding sources sinks. Global in include 128 Tg yr −1 from plant growth, 38 reactions CH 3 O 2 with itself other organic peroxy radicals, 23 decay, 13 biomass burning biofuels, 4 vehicles industry. The growth source is factor higher for young than mature leaves. lifetime 7 days; gas‐phase oxidation by OH accounts 63% sink, dry deposition land...
Abstract. Volatile and intermediate-volatility non-methane organic gases (NMOGs) released from biomass burning were measured during laboratory-simulated wildfires by proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF). We identified NMOG contributors to more than 150 PTR ion masses using gas chromatography (GC) pre-separation with electron ionization, H3O+ chemical NO+ an extensive literature review, time series correlation, providing higher certainty for identifications has...
Abstract. We present a detailed budget of formic and acetic acids, two the most abundant trace gases in atmosphere. Our bottom-up estimate global source acids are ~1200 ~1400 Gmol yr−1, dominated by photochemical oxidation biogenic volatile organic compounds, particular isoprene. Their sinks wet dry deposition. use GEOS-Chem chemical transport model to evaluate this against an extensive suite measurements from ground, ship satellite-based Fourier transform spectrometers, as well several...
We present measurements of organic aerosol (OA) in urban plumes from Houston and Dallas/Fort Worth as well industrial the area during TexAQS‐2006. Consistent with TexAQS‐2000 study, show greater amount mass downwind centers compared to areas. This is likely due higher emission processing volatile compounds (VOCs) sources along ship channel. Comparisons current observations northeastern (NE) United States indicate that observed ratios enhancement above background OA, ΔOA, CO, ΔCO, are within...
During the ARCPAC (Aerosol, Radiation, and Cloud Processes affecting Arctic Climate) airborne field experiment in April 2008 northern Alaska, about 50 plumes were encountered with NOAA WP‐3 aircraft between surface 6.5 km. Onboard measurements transport model FLEXPART showed that most of emitted by forest fires southern Siberia‐Lake Baikal area agricultural burning Kazakhstan‐southern Russia. Unexpectedly, these biomass dominant aerosol gas‐phase features this during April. The influence on...
Abstract. We construct a global atmospheric budget for acetaldehyde using 3-D model of chemistry (GEOS-Chem), and use an ensemble observations to evaluate present understanding its sources sinks. Hydrocarbon oxidation provides the largest source in (128 Tg a−1, factor 4 greater than previous estimate), with alkanes, alkenes, ethanol main precursors. There is also minor from isoprene oxidation. updated chemical mechanism GEOS-Chem, photochemical yields are consistent Master Chemical...
During the NEAQS‐ITCT2k4 campaign in New England, anthropogenic VOCs and CO were measured downwind from York City Boston. The emission ratios of relative to acetylene calculated using a method which ratio VOC with is plotted versus photochemical age. intercept at age zero gives ratio. so determined compared other measurement sets, including data same location 2002, canister samples collected inside Boston, aircraft measurements Los Angeles average urban composition 39 U.S. cities. All...
Abstract. An extensive program of experiments focused on biomass burning emissions began with a laboratory phase in which vegetative fuels commonly consumed prescribed fires were collected the southeastern and southwestern US burned series 71 at Forest Service Fire Sciences Laboratory Missoula, Montana. The particulate matter (PM2.5) measured by gravimetric filter sampling subsequent analysis for elemental carbon (EC), organic (OC), 38 elements. trace gas an open-path Fourier transform...
Airborne measurements of volatile organic compounds (VOCs) were performed during CalNex 2010 (California Research at the Nexus Air Quality and Climate Change) in Los Angeles (LA) basin May–June ITCT2k2 (Intercontinental Transport Chemical Transformation) May 2002. While CO 2 enhancements similar between two years, ΔCO/ΔCO ratio had decreased by about a factor two. The ΔVOC/ΔCO emission ratios stayed relatively constant years. This indicates that, relative to , VOCs LA also since These data...
Abstract. We present an overview of the background, scientific goals, and execution Aerosol, Radiation, Cloud Processes affecting Arctic Climate (ARCPAC) project April 2008. then summarize airborne measurements, made in troposphere Alaskan Arctic, aerosol particle size distributions, composition, optical properties discuss sources transport aerosols. The data were grouped into four categories based on gas-phase composition. First, background contained a relatively diffuse, sulfate-rich...
Detailed airborne, surface, and subsurface chemical measurements, primarily obtained in May June 2010, are used to quantify initial hydrocarbon compositions along different transport pathways (i.e., deep plumes, the surface slick, atmosphere) during Deepwater Horizon oil spill. Atmospheric measurements consistent with a limited area of surfacing oil, implications for leaked mass drop size distributions. The data further suggest relatively little variation leaking composition over time....
Abstract. Formic acid (HCOOH) is one of the most abundant acids in atmosphere, with an important influence on precipitation chemistry and acidity. Here we employ a chemical transport model (GEOS-Chem CTM) to interpret recent airborne ground-based measurements over US Southeast terms constraints they provide HCOOH sources sinks. Summertime boundary layer concentrations average several parts-per-billion, 2–3× larger than can be explained based known production loss pathways. This indicates or...
Abstract. Vegetation commonly managed by prescribed burning was collected from five southeastern and southwestern US military bases burned under controlled conditions at the Forest Service Fire Sciences Laboratory in Missoula, Montana. The smoke emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared (OP-FTIR) spectrometer for measurement gas-phase species. OP-FTIR detected quantified 19 species these fires: CO2, CO,...
Significance Recent work in Los Angeles has shown that urban volatile organic compound (VOC) emissions from consumer and industrial products—termed chemical products (VCPs)—are now an important source of ozone precursors. Using advancements VOC instrumentation, we show VCP are ubiquitous regions can be identified via unique fingerprints. Through detailed modeling, VCPs as to production fossil fuel VOCs the chemistry have significant impacts on model simulations key atmospheric processes....
Ground‐based and airborne volatile organic compound (VOC) measurements in Los Angeles, California, Paris, France, during the Research at Nexus of Air Quality Climate Change (CalNex) Megacities: Emissions, Urban, Regional Global Atmospheric Pollution Effects, Integrated Tools for Assessment Mitigation (MEGAPOLI) campaigns, respectively, are used to examine spatial variability composition anthropogenic VOC urban emissions evaluate regional emission inventories. Two independent methods that...
Abstract. A comprehensive suite of instruments was used to quantify the emissions over 200 organic gases, including methane and volatile compounds (VOCs), 9 inorganic gases from 56 laboratory burns 18 different biomass fuel types common in southeastern, southwestern, or northern US. gas chromatograph-mass spectrometry (GC-MS) instrument provided extensive chemical detail discrete air samples collected during a burn complemented by real-time measurements species via an open-path Fourier...