scholarly journals Long-term study of VOCs measured with PTR-MS at a rural site in New Hampshire with urban influences

2009 ◽  
Vol 9 (14) ◽  
pp. 4677-4697 ◽  
Author(s):  
C. Jordan ◽  
E. Fitz ◽  
T. Hagan ◽  
B. Sive ◽  
E. Frinak ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Proton Transfer Reaction ◽  
Early Morning ◽  
Rural Site ◽  
High Time Resolution ◽  
Data Set ◽  
Mixing Ratios ◽  
Long Term Study ◽  
Urban Rural

Abstract. A long-term, high time-resolution volatile organic compound (VOC) data set from a ground site that experiences urban, rural, and marine influences in the Northeastern United States is presented. A proton-transfer-reaction mass spectrometer (PTR-MS) was used to quantify 15 VOCs: a marine tracer dimethyl sulfide (DMS), a biomass burning tracer acetonitrile, biogenic compounds (monoterpenes, isoprene), oxygenated VOCs (OVOCs: methyl vinyl ketone (MVK) plus methacrolein (MACR), methanol, acetone, methyl ethyl ketone (MEK), acetaldehyde, and acetic acid), and aromatic compounds (benzene, toluene, C8 and C9 aromatics). Time series, overall and seasonal medians, with 10th and 90th percentiles, seasonal mean diurnal profiles, and inter-annual comparisons of mean summer and winter diurnal profiles are shown. Methanol and acetone exhibit the highest overall median mixing ratios 1.44 and 1.02 ppbv, respectively. Comparing the mean diurnal profiles of less well understood compounds (e.g., MEK) with better known compounds (e.g., isoprene, monoterpenes, and MVK + MACR) that undergo various controls on their atmospheric mixing ratios provides insight into possible sources of the lesser known compounds. The constant diurnal value of ~0.7 for the toluene:benzene ratio in winter, may possibly indicate the influence of wood-based heating systems in this region. Methanol exhibits an initial early morning release in summer unlike any other OVOC (or isoprene) and a dramatic late afternoon mixing ratio increase in spring. Although several of the OVOCs appear to have biogenic sources, differences in features observed between isoprene, methanol, acetone, acetaldehyde, and MEK suggest they are produced or emitted in unique ways.

scholarly journals Long-term study of VOCs measured with PTR-MS at a rural site in New Hampshire with urban influences

2009 ◽  
Vol 9 (1) ◽  
pp. 4251-4299
Author(s):  
C. Jordan ◽  
E. Fitz ◽  
T. Hagan ◽  
B. Sive ◽  
E. Frinak ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Proton Transfer Reaction ◽  
Early Morning ◽  
Rural Site ◽  
High Time Resolution ◽  
Data Set ◽  
Mixing Ratios ◽  
Long Term Study ◽  
Urban Rural

Abstract. A long-term, high time-resolution volatile organic compound (VOC) data set from a ground site that experiences urban, rural, and marine influences in the northeastern United States is presented. A proton-transfer-reaction mass spectrometer (PTR-MS) was used to quantify 15 VOCs: a marine tracer dimethyl sulfide (DMS), a biomass burning tracer acetonitrile, biogenic compounds (monoterpenes, isoprene), oxygenated VOCs (OVOCs: methyl vinyl ketone (MVK) plus methacrolein (MACR), methanol, acetone, methyl ethyl ketone (MEK), acetaldehyde, and acetic acid), and aromatic compounds (benzene, toluene, C8 and C9 aromatics). Time series, overall and seasonal medians, with 10th and 90th percentiles, seasonal mean diurnal profiles, and inter-annual comparisons of mean summer and winter diurnal profiles are shown. Methanol and acetone exhibit the highest overall median mixing ratios 1.44 and 1.02 ppbv, respectively. Comparing the mean diurnal profiles of less well understood compounds (e.g., MEK) with better known compounds (e.g., isoprene, monoterpenes, and MVK+MACR) that undergo various controls on their atmospheric mixing ratios provides insight into possible sources of the lesser known compounds. The constant diurnal value of ≈0.7 for the toluene:benzene ratio in winter, may possibly indicate the influence of wood-based heating systems in this region. Methanol exhibits an initial early morning release in summer unlike any other OVOC (or isoprene) and a dramatic late afternoon mixing ratio increase in spring. Although several of the OVOCs appear to have biogenic sources, differences in features observed between isoprene, methanol, acetone, acetaldehyde, and MEK suggest they are produced or emitted in unique ways.

scholarly journals Observations of NO<sub>x</sub>, ΣPNs, ΣANs, and HNO<sub>3</sub> at a Rural Site in the California Sierra Nevada Mountains: summertime diurnal cycles

2009 ◽  
Vol 9 (14) ◽  
pp. 4879-4896 ◽  
Author(s):  
D. A. Day ◽  
D. K. Farmer ◽  
A. H. Goldstein ◽  
P. J. Wooldridge ◽  
C. Minejima ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Sierra Nevada ◽  
Early Morning ◽  
Rural Site ◽  
Research Station ◽  
Alkyl Nitrates ◽  
Data Set ◽  
Diurnal Cycles ◽  
Mixing Ratios ◽  
Boundary Layer Dynamics

Abstract. Observations of NO, NO2, total peroxy nitrates (ΣPNs), total alkyl nitrates (ΣANs), HNO3, CO, O3, and meteorological parameters were obtained from October 2000 through February 2002 at 1315 m a.s.l., 38.9° N, 120.6° W on Sierra Pacific Industries land, adjacent to the University of California Blodgett Forest Research Station (UC-BFRS). We describe the data set with emphasis on the diurnal cycles during summertime 2001. We show that transport of the Sacramento urban plume is a primary factor responsible for diurnal variation in total reactive nitrogen mixing ratios as well as in NOx, ΣPNs and ΣANs, all of which exhibit a late afternoon/early evening peak. In contrast, HNO3 has a peak just after local noon indicating that HNO3 is in near steady state during the day with production due to photochemistry and removal by deposition and mixing with the background free troposphere. Boundary layer dynamics influence mixing ratios of all species in the early morning. Analysis of the morning feature suggests that higher mixing ratios of NOx and HNO3 persist in the residual layer than in the nocturnal boundary layer indicating the presence of nocturnal sinks of both species. Nighttime observations also indicate large HNO3 and ΣANs production through oxidation of alkenes by NO3.

scholarly journals Observations of NO<sub>x</sub>, ΣPNs, ΣANs, and HNO<sub>3</sub> at a rural site in the California Sierra Nevada Mountains: summertime diurnal cycles

2009 ◽  
Vol 9 (1) ◽  
pp. 3435-3483 ◽  
Author(s):  
D. A. Day ◽  
D. K. Farmer ◽  
A. H. Goldstein ◽  
P. J. Wooldridge ◽  
C. Minejima ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Sierra Nevada ◽  
Early Morning ◽  
Rural Site ◽  
Research Station ◽  
Alkyl Nitrates ◽  
Data Set ◽  
Diurnal Cycles ◽  
Mixing Ratios ◽  
Boundary Layer Dynamics

Abstract. Observations of NO, NO2, total peroxy nitrates (ΣPNs), total alkyl nitrates (ΣANs), HNO3, CO, O3, and meteorological parameters were obtained from October 2000 through February 2002 at 1315 m a.s.l., 38.97° N, 120.6° W on Sierra Pacific Industries land, adjacent to the University of California Blodgett Forest Research Station (UC-BFRS). We describe the data set with emphasis on the diurnal cycles during summertime 2001. We show that transport of the Sacramento urban plume is a primary factor responsible for diurnal variation in total reactive nitrogen mixing ratios as well as in NOx, ΣPNs and ΣANs, all of which exhibit a late afternoon/early evening peak. In contrast, HNO3 has a peak just after local noon indicating that HNO3 is in near steady state during the day with production due to photochemistry and removal by deposition and mixing with the background free troposphere. Boundary layer dynamics influence mixing ratios of all species in the early morning. Analysis of the morning feature suggests that higher mixing ratios of NOx and HNO3 persist in the residual layer than in the nocturnal boundary layer indicating the presence of nocturnal sinks of both species. Nighttime observations also indicate large HNO3 and ΣANs production through oxidation of alkenes by NO3.

scholarly journals Measurements of higher alkanes using NO<sup>+</sup> chemical ionization in PTR-ToF-MS: important contributions of higher alkanes to secondary organic aerosols in China

2020 ◽  
Vol 20 (22) ◽  
pp. 14123-14138
Author(s):  
Chaomin Wang ◽  
Bin Yuan ◽  
Caihong Wu ◽  
Sihang Wang ◽  
Jipeng Qi ◽  
...  
Keyword(s):  
Chemical Ionization ◽  
Secondary Organic Aerosols ◽  
Organic Aerosols ◽  
Proton Transfer Reaction ◽  
Rural Site ◽  
Urban Site ◽  
Accurate Estimation ◽  
High Time Resolution ◽  
The North ◽  
Tof Ms

Abstract. Higher alkanes are a major class of intermediate-volatility organic compounds (IVOCs), which have been proposed to be important precursors of secondary organic aerosols (SOA) in the atmosphere. Accurate estimation of SOA from higher alkanes and their oxidation processes in the atmosphere is limited, partially due to the difficulty of their measurement. High-time-resolution (10 s) measurements of higher alkanes were performed using NO+ chemical ionization in proton transfer reaction time-of-flight mass spectrometry (NO+ PTR-ToF-MS) at an urban site in Guangzhou in the Pearl River Delta (PRD) and at a rural site in the North China Plain (NCP). High concentrations were observed in both environments, with significant diurnal variations. At both sites, SOA production from higher alkanes is estimated from their photochemical losses and SOA yields. Higher alkanes account for significant fractions of SOA formation at the two sites, with average contributions of 7.0 % ± 8.0 % in Guangzhou and 9.4 % ± 9.1 % in NCP, which are comparable to or even higher than both single-ring aromatics and naphthalenes. The significant contributions of higher alkanes to SOA formation suggests that they should be explicitly included in current models for SOA formation. Our work also highlights the importance of NO+ PTR-ToF-MS in measuring higher alkanes and quantifying their contributions to SOA formation.

scholarly journals Technical Note: Determination of formaldehyde mixing ratios in polluted air with PTR-MS: laboratory experiments and field measurements

2007 ◽  
Vol 7 (5) ◽  
pp. 12845-12876
Author(s):  
S. Inomata ◽  
H. Tanimoto ◽  
S. Kameyama ◽  
U. Tsunogai ◽  
H. Irie ◽  
...  
Keyword(s):  
Proton Transfer ◽  
Field Measurements ◽  
Proton Transfer Reaction ◽  
Technical Note ◽  
Detection Sensitivity ◽  
Optical Absorption Spectroscopy ◽  
High Time Resolution ◽  
Mixing Ratios ◽  
Proton Transfer Reactions ◽  
Humidity Dependence

Abstract. Formaldehyde (HCHO), the most abundant carbonyl compound in the atmosphere, is generated as an intermediate product in the oxidation of nonmethane hydrocarbons. Proton transfer reaction mass spectrometry (PTR-MS) has the capability to detect HCHO from ion signals at m/z 31 with high time-resolution. However, the detection sensitivity is low compared to other detectable species, and is considerably affected by humidity, due to back reactions between protonated HCHO and water vapor prior to analysis. We performed a laboratory calibration of HCHO by PTR-MS and examined the detection sensitivity and humidity dependence at various field strengths. Subsequently, we deployed the PTR-MS instrument in a field campaign at Mount Tai in China in June 2006 to measure HCHO in various meteorological and photochemical conditions; we also conducted intercomparison measurements by Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS). Correction of interference in the m/z 31 signals by fragments from proton transfer reactions with methyl hydroperoxide, methanol, and ethanol greatly improves agreement between the two methods, giving the correlation [HCHO]MAX-DOAS = (0.99±0.16) [HCHO]PTR-MS + (0.02±0.38), where error limits represent 95% confidence levels.

scholarly journals N and Fe-Peak Elemental Abundances from IUE Co-Added Spectra of Hg-Mn and Normal Stars

1993 ◽  
Vol 138 ◽  
pp. 154-160
Author(s):  
Scott W. Roby ◽  
Saul J. Adelman ◽  
David S. Leckrone ◽  
Charles Cowley ◽  
Glenn M. Wahlgren
Keyword(s):  
Optical Spectra ◽  
High Quality ◽  
Term Study ◽  
Data Set ◽  
B Stars ◽  
Elemental Abundances ◽  
Long Term Study ◽  
Self Consistent ◽  
Good Agreement

AbstractLeckrone and Adelman have established an IUE observing strategy that has yielded co-added spectra with enhanced S/N ratios for several A and B stars. New observations by Roby and Adelman using the same technique have added two new Hg-Mn stars into this sample. We have begun a long-term study of elemental abundances in this uniform, high-quality set of IUE spectra for 13 stars. We report on the first stages of this project: abundances for N, Cr, Mn, Fe, Co, and Ni. The study of the Fe- peak elements show that our data set can provide accurate abundances and that abundances obtained from UV and optical spectra often are in good agreement. This study provides the groundwork for self-consistent abundance analyses of more exotic elements in our long term project.

scholarly journals Sources of long-lived atmospheric VOCs at the rural boreal forest site, SMEAR II

2015 ◽  
Vol 15 (23) ◽  
pp. 13413-13432 ◽  
Author(s):  
J. Patokoski ◽  
T. M. Ruuskanen ◽  
M. K. Kajos ◽  
R. Taipale ◽  
P. Rantala ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Forest Fires ◽  
Source Area ◽  
Proton Transfer Reaction ◽  
Composition Analysis ◽  
Forest Site ◽  
Concentration Data ◽  
Data Set ◽  
Source Areas ◽  
Mixing Ratios

Abstract. In this study a long-term volatile organic compound (VOCs) concentration data set, measured at the SMEAR II (Station for Measuring Ecosystem–Atmosphere Relations) boreal forest site in Hyytiälä, Finland during the years 2006–2011, was analyzed in order to identify source areas and profiles of the observed VOCs. VOC mixing ratios were measured using proton transfer reaction mass spectrometry. Four-day HYSPLIT 4 (Hybrid Single Particle Lagrangian Integrated Trajectory) backward trajectories and the Unmix 6.0 receptor model were used for source area and source composition analysis. Two major forest fire events in Russia took place during the measurement period. The effect of these fires was clearly visible in the trajectory analysis, lending confidence to the method employed with this data set. Elevated volume mixing ratios (VMRs) of non-biogenic VOCs related to forest fires, e.g. acetonitrile and aromatic VOCs, were observed. Ten major source areas for long-lived VOCs (methanol, acetonitrile, acetaldehyde, acetone, benzene, and toluene) observed at the SMEAR II site were identified. The main source areas for all the targeted VOCs were western Russia, northern Poland, Kaliningrad, and the Baltic countries. Industrial areas in northern continental Europe were also found to be source areas for certain VOCs. Both trajectory and receptor analysis showed that air masses from northern Fennoscandia were less polluted with respect to both the VOCs studied and other trace gases (CO, SO2 and NOx), compared to areas of eastern and western continental Europe, western Russia, and southern Fennoscandia.

scholarly journals A long-term study of cloud residuals from low-level Arctic clouds

2021 ◽  
Vol 21 (11) ◽  
pp. 8933-8959
Author(s):  
Linn Karlsson ◽  
Radovan Krejci ◽  
Makoto Koike ◽  
Kerstin Ebell ◽  
Paul Zieger
Keyword(s):  
Cloud Formation ◽  
Potential Contribution ◽  
Size Distributions ◽  
Term Study ◽  
Inlet System ◽  
Data Set ◽  
Minimum Concentration ◽  
Low Level ◽  
Long Term Study

Abstract. To constrain uncertainties in radiative forcings associated with aerosol–cloud interactions, improved understanding of Arctic cloud formation is required, yet long-term measurements of the relevant cloud and aerosol properties remain sparse. We present the first long-term study of cloud residuals, i.e. particles that were involved in cloud formation and cloud processes, in Arctic low-level clouds measured at Zeppelin Observatory, Svalbard. To continuously sample cloud droplets and ice crystals and separate them from non-activated aerosol, a ground-based counter-flow virtual impactor inlet system (GCVI) was used. A detailed evaluation of the GCVI measurements, using concurrent cloud particle size distributions, meteorological parameters, and aerosol measurements, is presented for both warm and cold clouds, and the potential contribution of sampling artefacts is discussed in detail. We find an excellent agreement of the GCVI sampling efficiency of liquid clouds using two independent approaches. The 2-year data set of cloud residual size distributions and number concentrations reveals that the cloud residuals follow the typical seasonal cycle of Arctic aerosol, with a maximum concentration in spring and summer and a minimum concentration in the late autumn and winter months. We observed average activation diameters in the range of 58–78 nm for updraught velocities below 1 m s−1. A cluster analysis also revealed cloud residual size distributions that were dominated by Aitken mode particles down to around 20–30 nm. During the winter months, some of these small particles may be the result of ice, snow, or ice crystal shattering artefacts in the GCVI inlet; however, cloud residuals down to 20 nm in size were also observed during conditions when artefacts are less likely.

scholarly journals Long-term NO<sub>x</sub> measurements in the remote marine tropical troposphere

2020 ◽  
Author(s):  
Simone T. Andersen ◽  
Lucy J. Carpenter ◽  
Beth S. Nelson ◽  
Luis Neves ◽  
Katie A. Read ◽  
...  
Keyword(s):  
Time Series ◽  
Light Emitting Diode ◽  
Ultra Violet ◽  
Data Set ◽  
Light Emitting ◽  
Mixing Ratios ◽  
Remote Troposphere ◽  
Tropical Troposphere ◽  
Term Data

Abstract. Atmospheric nitrogen oxides (NO + NO2 = NOx) have been measured at the Cape Verde Atmospheric Observatory (CVAO) in the tropical Atlantic (16° 51' N, 24° 52' W) since October 2006. These measurements represent a unique time series of NOx in the background remote troposphere. Nitrogen dioxide (NO2) is measured via photolytic conversion to nitric oxide (NO) by ultra violet light emitting diode arrays followed by chemiluminescence detection. Since the measurements began, a blue light converter (BLC) has been used for NO2 photolysis, with a maximum spectral output of 395 nm from 2006–2015 and of 385 nm from 2015. The original BLC used was constructed with a Teflon-like material and appeared to cause an overestimation of NO2 when illuminated. To avoid such interferences, a new additional photolytic converter (PLC) with a quartz photolysis cell (maximum spectral output also 385 nm) was implemented in March 2017. Once corrections are made for the NO2 artefact from the original BLC, the two NO2 converters are shown to give comparable NO2 mixing ratios (PLC = 0.92 × BLC, R2 = 0.92), giving confidence in the quantitative measurement of NOx at very low levels. Data analysis methods for the NOx measurements made at CVAO have been developed and applied to the entire time series to produce an internally consistent and high quality long-term data set. NO has a clear diurnal pattern with a maximum mixing ratio of 2–10 pptV during the day depending on the season and ~0 pptV during the night. NO2 shows a fairly flat diurnal signal, although a small increase in daytime NOx is evident in some months. Monthly average mixing ratios of NO2 vary between 5 and 30 pptV depending on the season. Clear seasonal trends in NO and NO2 levels can be observed with a maximum in autumn/winter and a minimum in spring/summer.

scholarly journals Dimethyl sulfide in the summertime Arctic atmosphere: measurements and source sensitivity simulations

2016 ◽  
Vol 16 (11) ◽  
pp. 6665-6680 ◽  
Author(s):  
Emma L. Mungall ◽  
Betty Croft ◽  
Martine Lizotte ◽  
Jennie L. Thomas ◽  
Jennifer G. Murphy ◽  
...  
Keyword(s):  
Dimethyl Sulfide ◽  
Transport Model ◽  
Sulfur Cycle ◽  
Oxidation Products ◽  
The Arctic ◽  
High Time Resolution ◽  
Study Region ◽  
Baffin Bay ◽  
Mixing Ratios ◽  
Arctic Atmosphere

Abstract. Dimethyl sulfide (DMS) plays a major role in the global sulfur cycle. In addition, its atmospheric oxidation products contribute to the formation and growth of atmospheric aerosol particles, thereby influencing cloud condensation nuclei (CCN) populations and thus cloud formation. The pristine summertime Arctic atmosphere is strongly influenced by DMS. However, atmospheric DMS mixing ratios have only rarely been measured in the summertime Arctic. During July–August, 2014, we conducted the first high time resolution (10 Hz) DMS mixing ratio measurements for the eastern Canadian Archipelago and Baffin Bay as one component of the Network on Climate and Aerosols: Addressing Key Uncertainties in Remote Canadian Environments (NETCARE). DMS mixing ratios ranged from below the detection limit of 4 to 1155 pptv (median 186 pptv) during the 21-day shipboard campaign. A transfer velocity parameterization from the literature coupled with coincident atmospheric and seawater DMS measurements yielded air–sea DMS flux estimates ranging from 0.02 to 12 µmol m−2 d−1. Air-mass trajectory analysis using FLEXPART-WRF and sensitivity simulations with the GEOS-Chem chemical transport model indicated that local sources (Lancaster Sound and Baffin Bay) were the dominant contributors to the DMS measured along the 21-day ship track, with episodic transport from the Hudson Bay System. After adjusting GEOS-Chem oceanic DMS values in the region to match measurements, GEOS-Chem reproduced the major features of the measured time series but was biased low overall (2–1006 pptv, median 72 pptv), although within the range of uncertainty of the seawater DMS source. However, during some 1–2 day periods the model underpredicted the measurements by more than an order of magnitude. Sensitivity tests indicated that non-marine sources (lakes, biomass burning, melt ponds, and coastal tundra) could make additional episodic contributions to atmospheric DMS in the study region, although local marine sources of DMS dominated. Our results highlight the need for both atmospheric and seawater DMS data sets with greater spatial and temporal resolution, combined with further investigation of non-marine DMS sources for the Arctic.

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