Mixing ratio
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Radical chemistry at a rural site (Wangdu) in the North China Plain: observation and model calculations of OH, HO <sub>2</sub> and RO <sub>2</sub> radicals Open
A comprehensive field campaign was carried out in summer 2014 in Wangdu, located in the North China Plain. A month of continuous OH, HO2 and RO2 measurements was achieved. Observations of radicals by the laser-induced fluorescence (LIF) te…
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The role of chlorine in global tropospheric chemistry Open
We present a comprehensive simulation of tropospheric chlorine within the GEOS-Chem global 3-D model of oxidant–aerosol–halogen atmospheric chemistry. The simulation includes explicit accounting of chloride mobilization from sea salt aeros…
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Contributions of different anthropogenic volatile organic compound sources to ozone formation at a receptor site in the Pearl River Delta region and its policy implications Open
Volatile organic compounds (VOCs) are key precursors of photochemical smog. Quantitatively evaluating the contributions of VOC sources to ozone (O3) formation could provide valuable information for emissions control and photochemical pollu…
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The CAMS interim Reanalysis of Carbon Monoxide, Ozone and Aerosol for 2003–2015 Open
A new global reanalysis data set of atmospheric composition (AC) for the period 2003–2015 has been produced by the Copernicus Atmosphere Monitoring Service (CAMS). Satellite observations of total column (TC) carbon monoxide (CO) and aeroso…
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Significant concentrations of nitryl chloride sustained in the morning: investigations of the causes and impacts on ozone production in a polluted region of northern China Open
Nitryl chloride (ClNO2) is a dominant source of chlorine radical in polluted environment, and can significantly affect the atmospheric oxidative chemistry. However, the abundance of ClNO2 and its exact role are not fully understood under d…
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Emission and Evolution of Submicron Organic Aerosol in Smoke from Wildfires in the Western United States Open
Despite increasing incidence of wildfires in the United States, wildfire smoke is poorly characterized, with little known about particle composition and emission rates. Chemistry in transported plumes confounds interpretation of ground and…
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Black carbon radiative effects highly sensitive to emitted particle size when resolving mixing-state diversity Open
Post-industrial increases in atmospheric black carbon (BC) have a large but uncertain warming contribution to Earth’s climate. Particle size and mixing state determine the solar absorption efficiency of BC and also strongly influence how e…
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New insights into the column CH<sub>2</sub>O/NO<sub>2</sub> ratio as an indicator of near‐surface ozone sensitivity Open
Satellite‐based measurements of the column CH 2 O/NO 2 ratio have previously been used to estimate near‐surface ozone (O 3 ) sensitivity (i.e., NO x or VOC limited), and the forthcoming launch of air quality‐focused geostationary satellite…
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Observations of nitryl chloride and modeling its source and effect on ozone in the planetary boundary layer of southern China Open
Nitryl chloride (ClNO 2 ) plays potentially important roles in atmospheric chemistry, but its abundance and effect are not fully understood due to the small number of ambient observations of ClNO 2 to date. In late autumn 2013, ClNO 2 was …
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Heterogeneous N<sub>2</sub>O<sub>5</sub> Uptake During Winter: Aircraft Measurements During the 2015 WINTER Campaign and Critical Evaluation of Current Parameterizations Open
Nocturnal dinitrogen pentoxide (N 2 O 5 ) heterogeneous chemistry impacts regional air quality and the distribution and lifetime of tropospheric oxidants. Formed from the oxidation of nitrogen oxides, N 2 O 5 is heterogeneously lost to aer…
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Near‐Complete Local Reduction of Arctic Stratospheric Ozone by Severe Chemical Loss in Spring 2020 Open
In the Antarctic ozone hole, ozone mixing ratios have been decreasing to extremely low values of 0.01–0.1 ppm in nearly all spring seasons since the late 1980s, corresponding to 95–99% local chemical loss. In contrast, Arctic ozone loss ha…
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Global tropospheric halogen (Cl, Br, I) chemistry and its impact on oxidants Open
We present an updated mechanism for tropospheric halogen (Cl + Br + I) chemistry in the GEOS-Chem global atmospheric chemical transport model and apply it to investigate halogen radical cycling and implications for tropospheric oxidants. I…
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Characterization of VOCs and their related atmospheric processes in a central Chinese city during severe ozone pollution periods Open
A 5-month campaign (from May to September 2017) was conducted to characterize volatile organic compounds (VOCs) for the first time at four sites in Zhengzhou, Henan Province, China, where ground level ozone (O3) concentration has shown an …
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Characterization of ambient volatile organic compounds and their sources in Beijing, before, during, and after Asia-Pacific Economic Cooperation China 2014 Open
Ambient volatile organic compounds (VOCs) were measured using an online system, gas chromatography–mass spectrometry/flame ionization detector (GC-MS/FID), in Beijing, China, before, during, and after Asia-Pacific Economic Cooperation (APE…
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Real-time measurements of secondary organic aerosol formation and aging from ambient air in an oxidation flow reactor in the Los Angeles area Open
Field studies in polluted areas over the last decade have observed large formation of secondary organic aerosol (SOA) that is often poorly captured by models. The study of SOA formation using ambient data is often confounded by the effects…
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Elevated levels of OH observed in haze events during wintertime in central Beijing Open
Wintertime in situ measurements of OH, HO2 and RO2 radicals and OH reactivity were made in central Beijing during November and December 2016. Exceptionally elevated NO was observed on occasions, up to ∼250 ppbv. The daily maximum mixing ra…
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First Reprocessing of Southern Hemisphere ADditional OZonesondes Profile Records: 3. Uncertainty in Ozone Profile and Total Column Open
Reprocessed ozonesonde data from eight SHADOZ (Southern Hemisphere ADditional OZonesondes) sites have been used to derive the first analysis of uncertainty estimates for both profile and total column ozone (TCO). The ozone uncertainty is a…
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Daytime formation of nitrous acid at a coastal remote site in Cyprus indicating a common ground source of atmospheric HONO and NO Open
Characterization of daytime sources of nitrous acid (HONO) is crucial to understand atmospheric oxidation and radical cycling in the planetary boundary layer. HONO and numerous other atmospheric trace constituents were measured on the Medi…
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Semi-quantitative understanding of source contribution to nitrous acid (HONO) based on 1 year of continuous observation at the SORPES station in eastern China Open
Nitrous acid (HONO), an important precursor of the hydroxyl radical (OH), has long been recognized as of significance to atmospheric chemistry, but its sources are still debated. In this study, we conducted continuous measurement of HONO f…
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A new airborne laser-induced fluorescence instrument for in situ detection of formaldehyde throughout the troposphere and lower stratosphere Open
The NASA In Situ Airborne Formaldehyde (ISAF) instrument is a high-performance laser-based detector for gas-phase formaldehyde (HCHO). ISAF uses rotational-state specific laser excitation at 353 nm for laser-induced fluorescence (LIF) dete…
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Nighttime chemistry at a high altitude site above Hong Kong Open
Nighttime reactions of nitrogen oxides influence ozone, volatile organic compounds, and aerosol and are thus important to the understanding of regional air quality. Despite large emissions and rapid recent growth of nitrogen oxide concentr…
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Methane and carbon dioxide fluxes over a lake: comparison between eddy covariance, floating chambers and boundary layer method Open
Freshwaters bring a notable contribution to the global carbon budget by emitting both carbon dioxide (CO2) and methane (CH4) to the atmosphere. Global estimates of freshwater emissions traditionally use a wind-speed-based gas transfer velo…
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Isotopic exchange on the diurnal scale between near-surface snow and lower atmospheric water vapor at Kohnen station, East Antarctica Open
Quantifying the magnitude of post-depositional processes affecting the isotopic composition of surface snow is essential for a more accurate interpretation of ice core data. To achieve this, high temporal resolution measurements of both lo…
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Net ozone production and its relationship to nitrogen oxides and volatile organic compounds in the marine boundary layer around the Arabian Peninsula Open
Strongly enhanced tropospheric ozone (O3) mixing ratios have been reported in the Arabian Basin, a region with intense solar radiation and high concentrations of O3 precursors such as nitrogen oxides (NOx) and volatile organic compounds (V…
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Causes of a continuous summertime O <sub>3</sub> pollution event in Jinan, a central city in the North China Plain Open
In the summer of 2017, measurements of ozone (O3) and its precursors were carried out at an urban site in Jinan, a central city in the North China Plain (NCP). A continuous O3 pollution event was captured during 4–11 August, with the maxim…
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Inter-model comparison of global hydroxyl radical (OH) distributions and their impact on atmospheric methane over the 2000–2016 period Open
The modeling study presented here aims to estimate how uncertainties in global hydroxyl radical (OH) distributions, variability, and trends may contribute to resolving discrepancies between simulated and observed methane (CH4) changes sinc…
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Water Vapor Vertical Profiles on Mars in Dust Storms Observed by TGO/NOMAD Open
It has been suggested that dust storms efficiently transport water vapor from the near‐surface to the middle atmosphere on Mars. Knowledge of the water vapor vertical profile during dust storms is important to understand water escape. Duri…
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Influence of oil and gas emissions on summertime ozone in the Colorado Northern Front Range Open
Tropospheric O 3 has been decreasing across much of the eastern U.S. but has remained steady or even increased in some western regions. Recent increases in VOC and NO x emissions associated with the production of oil and natural gas (O&NG)…
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Emissions of Reactive Nitrogen From Western U.S. Wildfires During Summer 2018 Open
Reactive nitrogen ( N r ) within smoke plumes plays important roles in the production of ozone, the formation of secondary aerosols, and deposition of fixed N to ecosystems. The Western Wildfire Experiment for Cloud Chemistry, Aerosol Abso…
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MAX-DOAS measurements of tropospheric NO <sub>2</sub> and HCHO in Munich and the comparison to OMI and TROPOMI satellite observations Open
We present two-dimensional scanning Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations of nitrogen dioxide (NO2) and formaldehyde (HCHO) in Munich. Vertical columns and vertical distribution profiles of aerosol…