scholarly journals Measuring atmospheric naphthalene with laser-induced fluorescence

2004 ◽  
Vol 4 (1) ◽  
pp. 343-363 ◽  
Author(s):  
M. Martinez ◽  
H. Harder ◽  
X. Ren ◽  
R. L. Lesher ◽  
W. H. Brune
Keyword(s):  
New York ◽  
New York City ◽  
Gas Phase ◽  
Laser Induced Fluorescence ◽  
Integration Time ◽  
Mixing Ratio ◽  
Quenching Rate ◽  
Anthropogenic Pollutants ◽  
Mixing Ratios ◽  
Instrument Configuration

Abstract. A new method for measuring gas-phase naphthalene in the atmosphere is based on laser-induced fluorescence at low pressure. The fluorescence spectrum of naphthalene near 308 nm was identified. Naphthalene fluorescence quenching by N2, O2 and H2O was investigated in the laboratory. No significant quenching was found for H2O with mixing ratio up to 2.5%. The quenching rate of naphthalene fluorescence is (1.98±0.18)×10−11 cm3 molecule−1 s−1 for N2, and (2.48±0.08)×10−10 cm3 molecule−1 s−1 for O2 at 297 K. Instrument calibrations were performed with a range of naphthalene mixing ratios between 5 and 80 parts per billion by volume (ppbv, 10−9. In the current instrument configuration, the detection limit is estimated to be about 20 parts per trillion by volume (pptv, 10−12) with 2σ confidence and a 1-min integration time. Measurement of atmospheric naphthalene in three cities, Nashville, TN, Houston, TX, and New York City, NY, are presented. Good correlation between naphthalene and major anthropogenic pollutants is found.

scholarly journals Measuring atmospheric naphthalene with laser-induced fluorescence

2004 ◽  
Vol 4 (2) ◽  
pp. 563-569 ◽  
Author(s):  
M. Martinez ◽  
H. Harder ◽  
X. Ren ◽  
R. L. Lesher ◽  
W. H. Brune
Keyword(s):  
New York ◽  
New York City ◽  
Gas Phase ◽  
Laser Induced Fluorescence ◽  
Integration Time ◽  
Mixing Ratio ◽  
Quenching Rate ◽  
Anthropogenic Pollutants ◽  
Mixing Ratios ◽  
Instrument Configuration

Abstract. A new method for measuring gas-phase naphthalene in the atmosphere is based on laser-induced fluorescence at low pressure. The fluorescence spectrum of naphthalene near 308 nm was identified. Naphthalene fluorescence quenching by N, O and HO was investigated in the laboratory. No significant quenching was found for HO with mixing ratio up to 2.5%. The quenching rate of naphthalene fluorescence is (1.980.18) 10cmmolecules for N, and (2.480.08)10cmmolecules for O at 297 K. Instrument calibrations were performed with a range of naphthalene mixing ratios between 5 and 80 parts per billion by volume (ppbv, 10. In the current instrument configuration, the detection limit is estimated to be about 20 parts per trillion by volume (pptv, 10 with 2 confidence and a 1-min integration time. Measurements of atmospheric naphthalene in three cities, Nashville, TN, Houston, TX, and New York City, NY, are presented. Good correlation between naphthalene and major anthropogenic pollutants is found.

scholarly journals Modeling ozone plumes observed downwind of New York City over the North Atlantic Ocean during the ICARTT field campaign

2011 ◽  
Vol 11 (14) ◽  
pp. 7375-7397 ◽  
Author(s):  
S.-H. Lee ◽  
S.-W. Kim ◽  
M. Trainer ◽  
G. J. Frost ◽  
S. A. McKeen ◽  
...  
Keyword(s):  
New York ◽  
New York City ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
York City ◽  
North Atlantic Ocean ◽  
Mixing Ratios ◽  
The North ◽  
The North Atlantic ◽  
Urban Plumes

Abstract. Transport and chemical transformation of well-defined New York City (NYC) urban plumes over the North Atlantic Ocean were studied using aircraft measurements collected on 20–21 July 2004 during the ICARTT (International Consortium for Atmospheric Research on Transport and Transformation) field campaign and WRF-Chem (Weather Research and Forecasting-Chemistry) model simulations. The strong NYC urban plumes were characterized by carbon monoxide (CO) mixing ratios of 350–400 parts per billion by volume (ppbv) and ozone (O3) levels of about 100 ppbv near New York City on 20 July in the WP-3D in-situ and DC-3 lidar aircraft measurements. On 21 July, the two aircraft captured strong urban plumes with about 350 ppbv CO and over 150 ppbv O3 (~160 ppbv maximum) about 600 km downwind of NYC over the North Atlantic Ocean. The measured urban plumes extended vertically up to about 2 km near New York City, but shrank to 1–1.5 km over the stable marine boundary layer (MBL) over the North Atlantic Ocean. The WRF-Chem model reproduced ozone formation processes, chemical characteristics, and meteorology of the measured urban plumes near New York City (20 July) and in the far downwind region over the North Atlantic Ocean (21 July). The quasi-Lagrangian analysis of transport and chemical transformation of the simulated NYC urban plumes using WRF-Chem results showed that the pollutants can be efficiently transported in (isentropic) layers in the lower atmosphere (<2–3 km) over the North Atlantic Ocean while maintaining a dynamic vertical decoupling by cessation of turbulence in the stable MBL. The O3 mixing ratio in the NYC urban plumes remained at 80–90 ppbv during nocturnal transport over the stable MBL, then grew to over 100 ppbv by daytime oxidation of nitrogen oxides (NOx = NO + NO2) with mixing ratios on the order of 1 ppbv. Efficient transport of reactive nitrogen species (NOy), specifically nitric acid (HNO3), was confirmed through the comparison of the CO/NOy ratio in photochemically fresh and aged NYC plumes, implying the possibility of long-range transport of O3 over the stable MBL over the North Atlantic Ocean in association with NOx regeneration mechanism. The impact of chemical initial and boundary conditions (IC/BCs) on modelled O3 urban plumes was investigated in terms of the background O3 level and the vertical structure of the urban plumes. Simulations with dynamic ("time-variant") chemical IC/BCs enhanced the O3 level by 2–12 ppbv on average in the atmospheric layer below 3 km, showing better agreement with the observed NYC plumes and biomass-burning plumes than the simulation with prescribed static IC/BCs. The simulation including MOZART-4 chemical IC/BCs and Alaskan/Canadian wildfire emissions compared better to the observed O3 profiles in the upper atmospheric layer (>~3 km) than models that only accounted for North American anthropogenic/biogenic and wildfire contributions to background ozone. The comparison between models and observations show that chemical IC/BCs must be properly specified to achieve accurate model results.

scholarly journals Intercomparison of Hantzsch and fiber-laser-induced-fluorescence formaldehyde measurements

2014 ◽  
Vol 7 (1) ◽  
pp. 233-255 ◽  
Author(s):  
J. Kaiser ◽  
X. Li ◽  
R. Tillmann ◽  
I. Acir ◽  
F. Rohrer ◽  
...  
Keyword(s):  
Linear Regression ◽  
Fiber Laser ◽  
Gas Phase ◽  
Measurement Techniques ◽  
Laser Induced Fluorescence ◽  
Mixing Ratios ◽  
Wet Chemical ◽  
Simulation Chamber

Abstract. Two gas-phase formaldehyde (HCHO) measurement techniques, a modified commercial wet-chemical instrument based on Hantzsch Fluorimetry and a custom-built instrument based on Fiber-Laser Induced Fluorescence (FILIF), were deployed at the atmospheric simulation chamber SAPHIR to compare the instruments' performances under a range of conditions. Thermolysis of para-HCHO and ozonolysis of 1-butene were used as HCHO sources, allowing for calculations of theoretical HCHO mixing ratios. Calculated HCHO mixing ratios are compared to measurements, and the two measurements are also compared. Experiments were repeated under dry and humid conditions (RH < 2% and RH > 60%) to investigate the possibility of a water artifact in the FILIF measurements. The ozonolysis of 1-butene also allowed for the investigation of an ozone artifact seen in some Hantzsch measurements in previous intercomparisons. Results show that under all conditions the two techniques are well correlated (R2 ≥ 0.997), and linear regression statistics show measurements agree with within stated uncertainty (15% FILIF + 5% Hantzsch). No water or ozone artifacts are identified.

scholarly journals Seasonal variation of peroxyacetylnitrate (PAN) in coastal Antarctica measured with a new instrument for the detection of sub-part per trillion mixing ratios of PAN

2007 ◽  
Vol 7 (17) ◽  
pp. 4589-4599 ◽  
Author(s):  
G. P. Mills ◽  
W. T. Sturges ◽  
R. A. Salmon ◽  
S. J.-B. Bauguitte ◽  
K. A. Read ◽  
...  
Keyword(s):  
Gas Phase ◽  
Research Station ◽  
Mixing Ratio ◽  
Gas Chromatograph ◽  
Mixing Ratios ◽  
New Instrument ◽  
Summer Minimum ◽  
Antarctic Boundary Layer ◽  
The Antarctic ◽  
Measurement Period

Abstract. An automated gas chromatograph with sample pre-concentration for the measurement of peroxyacetylnitrate (PAN) was constructed with a minimum detection limit below 1 pptv. This instrument was deployed at the British Antarctic Survey's Halley Research Station, Antarctica (75.6° S, 26.6° W) as part of the CHABLIS (Chemistry of the Antarctic Boundary Layer and the Interface with Snow) campaign. Hourly measurements were carried out between July 2004 and February 2005 with observed maximum and minimum mixing ratios of 52.3 and <0.6 pptv, respectively with a mean PAN mixing ratio for the measurement period of 9.2 pptv (standard deviation: 6.2 pptv). The changes in PAN mixing ratios typically occurred over periods of several days to a week and showed a strong similarity to the variation in alkenes. The mixing ratio of PAN at Halley has a possible seasonal cycle with a winter maximum and summer minimum, though the cycle is incomplete and the data are very variable. Calculations indicate that gross local PAN production is approximately 1 pptv d−1 in spring and 0.6 pptv d−1 in summer. Net loss of PAN transported to Halley in the summer is a small gas-phase source of NOx and net production of PAN in the spring is a very small NOx sink.

scholarly journals Intercomparison of Hantzsch and fiber-laser-induced-fluorescence formaldehyde measurements

2014 ◽  
Vol 7 (6) ◽  
pp. 1571-1580 ◽  
Author(s):  
J. Kaiser ◽  
X. Li ◽  
R. Tillmann ◽  
I. Acir ◽  
F. Holland ◽  
...  
Keyword(s):  
Fiber Laser ◽  
Gas Phase ◽  
Measurement Techniques ◽  
Laser Induced Fluorescence ◽  
Reaction Chamber ◽  
Mixing Ratios ◽  
Low Concentrations ◽  
Wet Chemical ◽  
Single Instrument ◽  
Instrument Sensitivity

Abstract. Two gas-phase formaldehyde (HCHO) measurement techniques, a modified commercial wet-chemical instrument based on Hantzsch fluorimetry and a custom-built instrument based on fiber laser-induced fluorescence (FILIF), were deployed at the atmospheric simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) to compare the instruments' performances under a range of conditions. Thermolysis of para-HCHO and ozonolysis of 1-butene were used as HCHO sources, allowing for calculations of theoretical HCHO mixing ratios. Calculated HCHO mixing ratios are compared to measurements, and the two measurements are also compared. Experiments were repeated under dry and humid conditions (RH < 2% and RH > 60%) to investigate the possibility of a water artifact in the FILIF measurements. The ozonolysis of 1-butene also allowed for the investigation of an ozone artifact seen in some Hantzsch measurements in previous intercomparisons. Results show that under all conditions the two techniques are well correlated (R2 ≥ 0.997), and linear regression statistics show measurements agree with within stated uncertainty (15% FILIF + 5% Hantzsch). No water or ozone artifacts are identified. While a slight curvature is observed in some Hantzsch vs. FILIF regressions, the potential for variable instrument sensitivity cannot be attributed to a single instrument at this time. Measurements at low concentrations highlight the need for a secondary method for testing the purity of air used in instrument zeroing and the need for further FILIF White cell outgassing experiments.

scholarly journals Detection of dimethylamine in the low pptv range using nitrate chemical ionization atmospheric pressure interface time-of-flight (CI-APi-TOF) mass spectrometry

2016 ◽  
Vol 9 (5) ◽  
pp. 2135-2145 ◽  
Author(s):  
Mario Simon ◽  
Martin Heinritzi ◽  
Stephan Herzog ◽  
Markus Leiminger ◽  
Federico Bianchi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Phase ◽  
Atmospheric Pressure ◽  
Chemical Ionization ◽  
Integration Time ◽  
Ionization Mass ◽  
Mixing Ratios ◽  
Highly Sensitive ◽  
Volatile Organic ◽  
Cluster Ion

Abstract. Amines are potentially important for atmospheric new particle formation, but their concentrations are usually low with typical mixing ratios in the pptv range or even smaller. Therefore, the demand for highly sensitive gas-phase amine measurements has emerged in the last several years. Nitrate chemical ionization mass spectrometry (CIMS) is routinely used for the measurement of gas-phase sulfuric acid in the sub-pptv range. Furthermore, extremely low volatile organic compounds (ELVOCs) can be detected with a nitrate CIMS. In this study we demonstrate that a nitrate CIMS can also be used for the sensitive measurement of dimethylamine (DMA, (CH3)2NH) using the NO3−•(HNO3)1 − 2• (DMA) cluster ion signal. Calibration measurements were made at the CLOUD chamber during two different measurement campaigns. Good linearity between 0 and  ∼  120 pptv of DMA as well as a sub-pptv detection limit of 0.7 pptv for a 10 min integration time are demonstrated at 278 K and 38 % RH.

scholarly journals Seasonal variation of peroxyacetylnitrate (PAN) in coastal Antarctica measured with a new instrument for the detection of sub-part per trillion mixing ratios of PAN

2007 ◽  
Vol 7 (2) ◽  
pp. 5617-5645
Author(s):  
G. P. Mills ◽  
W. T. Sturges ◽  
R. A. Salmon ◽  
S. J.-B. Bauguitte ◽  
K. A. Read ◽  
...  
Keyword(s):  
Gas Phase ◽  
Research Station ◽  
Mixing Ratio ◽  
Gas Chromatograph ◽  
Mixing Ratios ◽  
New Instrument ◽  
Summer Minimum ◽  
Antarctic Boundary Layer ◽  
The Antarctic ◽  
Measurement Period

Abstract. An automated gas chromatograph with sample pre-concentration for the measurement of peroxyacetylnitrate (PAN) was constructed with a minimum detection limit below 1 pptv. This instrument was deployed at the British Antarctic Survey's Halley Research Station, Antarctica (75.6° S, 26.6° W) as part of the CHABLIS (Chemistry of the Antarctic Boundary Layer and the Interface with Snow) campaign. Hourly measurements were carried out between July 2004 and February 2005 with observed maximum and minimum mixing ratios of 52.3 and <0.6 pptv, respectively with a mean PAN mixing ratio for the measurement period of 9.2 pptv (standard deviation: 6.2 pptv). The changes in PAN mixing ratios typically occurred over periods of several days to a week and showed a strong similarity to the variation in alkenes. The mixing ratio of PAN at Halley has a possible seasonal cycle with a winter maximum and summer minimum, though the cycle is incomplete and the data is very variable. Calculations indicate that gross local PAN production is approximately 1pptv d−1 in spring and 0.6 pptv d−1 in summer. Net loss of PAN transported to Halley in the summer is a small gas-phase source of NOx and net production of PAN in the spring is a very small NOx sink .

scholarly journals Modeling ozone plumes observed downwind of New York City over the North Atlantic Ocean during the ICARTT field campaign

2011 ◽  
Vol 11 (5) ◽  
pp. 14031-14089
Author(s):  
S.-H. Lee ◽  
S.-W. Kim ◽  
M. Trainer ◽  
G. J. Frost ◽  
S. A. McKeen ◽  
...  
Keyword(s):  
New York ◽  
New York City ◽  
Atlantic Ocean ◽  
North Atlantic ◽  
York City ◽  
North Atlantic Ocean ◽  
Mixing Ratios ◽  
The North ◽  
The North Atlantic ◽  
Urban Plumes

Abstract. Transport and chemical transformation of well-defined New York City (NYC) urban plumes over the North Atlantic Ocean were studied using aircraft measurements collected on 20–21 July 2004 during the ICARTT (International Consortium for Atmospheric Research on Transport and Transformation) field campaign and WRF-Chem (Weather Research and Forecasting-Chemistry) model simulations. The strong NYC urban plumes were characterized by carbon monoxide (CO) mixing ratios of 350–400 parts per billion by volume (ppbv) and ozone (O3) levels of about 100 ppbv near New York City on 20 July in the WP-3D in-situ and DC-3 lidar aircraft measurements. On 21 July, the two aircraft captured strong urban plumes with about 350 ppbv CO and over 150 ppbv O3 (~160 ppbv maximum) about 600 km downwind of NYC over the North Atlantic Ocean. The measured urban plumes extended vertically up to about 2 km near New York City, but shrank to 1–1.5 km over the stable marine boundary layer (MBL) over the North Atlantic Ocean. The WRF-Chem model reproduced ozone formation processes, chemical characteristics, and meteorology of the measured urban plumes near New York City (20 July) and in the far downwind region over the North Atlantic Ocean (21 July). The quasi-Lagrangian analysis of transport and chemical transformation of the simulated NYC urban plumes using WRF-Chem results showed that the pollutants can be efficiently transported in (isentropic) layers in the lower atmosphere (<2–3 km) over the North Atlantic Ocean while maintaining a dynamic vertical decoupling by cessation of turbulence in the stable MBL. The O3 mixing ratio in the NYC urban plumes remained at 80–90 ppbv during nocturnal transport over the stable MBL, then grew to over 100 ppbv by daytime oxidation of nitrogen oxides (NOx = NO + NO2) with mixing ratios on the order of 1 ppbv. Efficient transport of reactive nitrogen species (NOy), specifically nitric acid (HNO3), was confirmed through the comparison of the CO/NOy ratio in photochemically fresh and aged NYC plumes, implying the possibility of long-range transport of O3 over the stable MBL over the North Atlantic Ocean in association with NOx regeneration mechanism. The impact of chemical initial and boundary conditions (IC/BCs) on modelled O3 urban plumes was investigated in terms of the background O3 level and the vertical structure of the urban plumes. Simulations with dynamic chemical IC/BCs enhanced the O3 level by 2–12 ppbv on average in the atmospheric layer below 3 km, showing better agreement with the observed NYC plumes and biomass-burning plumes than the simulation with prescribed static IC/BCs. The simulation including MOZART-4 chemical IC/BCs and Alaskan/Canadian wildfire emissions compared better to the observed O3 profiles in the upper atmospheric layer (>~3 km) than models that only accounted for North American anthropogenic/biogenic and wildfire contributions to background ozone. The comparison between models and observations show that chemical IC/BCs must be properly specified to achieve accurate model results.

scholarly journals What do we learn about bromoform transport and chemistry in deep convection from fine scale modelling?

2012 ◽  
Vol 12 (14) ◽  
pp. 6073-6093 ◽  
Author(s):  
V. Marécal ◽  
M. Pirre ◽  
G. Krysztofiak ◽  
P. D. Hamer ◽  
B. Josse
Keyword(s):  
Boundary Layer ◽  
Production Process ◽  
Gas Phase ◽  
Aqueous Phase ◽  
Convective Cloud ◽  
Mixing Ratio ◽  
Atmospheric Conditions ◽  
Cloud Droplets ◽  
Upper Troposphere ◽  
Mixing Ratios

Abstract. Bromoform is one of the most abundant halogenated Very Short-Lived Substances (VSLS) that possibly contributes, when degradated, to the inorganic halogen loading in the stratosphere. In this paper we present a detailed modelling study of the transport and the photochemical degradation of bromoform and its product gases (PGs) in a tropical convective cloud. The aim was to explore the transport and chemistry of bromoform under idealised conditions at the cloud scale. We used a 3-D cloud-resolving model coupled with a chemistry model including gaseous and aqueous chemistry. In particular, our model features explicit partitioning of the PGs between the gas phase and the aqueous phase based on newly calculated Henry's law coefficients using theoretical methods. We ran idealised simulations for up to 10 days that were initialised using a tropical radiosounding of atmospheric conditions and using outputs from a global chemistry-transport model for chemical species. Two simulations were run with stable atmospheric conditions with a bromoform initial mixing ratio of 40 pptv (part per trillion by volume) and 1.6 pptv up to 1 km altitude. The first simulation corresponds to high bromoform mixing ratios that are representative of real values found near strong localised sources (e.g. tropical coastal margins) and the second to the global tropical mean mixing ratio from observations. Both of these simulations show that the sum of bromoform and its PGs significantly decreases with time because of dry deposition, and that PGs are mainly in the form of HBr after 2 days of simulation. Two further simulations are conducted; these are similar to the first two simulations but include perturbations of temperature and moisture leading to the development of a convective cloud reaching the tropical tropopause layer (TTL). Results of these simulations show an efficient vertical transport of the bromoform from the boundary layer to the upper troposphere and the TTL. The bromoform mixing ratio in the TTL is up to 45% of the initial boundary layer mixing ratio. The most abundant organic PGs, which are not very soluble, are also uplifted efficiently in both simulations featuring the convective perturbation. The inorganic PGs are more abundant than the organic PGs, and their mixing ratios in the upper troposphere and in the TTL depend on the partitioning between inorganic soluble and insoluble species in the convective cloud. Important soluble species such as HBr and HOBr are efficiently scavenged by rain. This removal of Bry by rain is reduced by the release of Br2 (relatively insoluble) to the gas phase due to aqueous chemistry processes in the cloud droplets. The formation of Br2 in the aqueous phase and its subsequent release to the gas phase makes a non negligible contribution to the high altitude bromine budget in the case of the large bromoform (40 pptv) initial mixing ratios. In this specific, yet realistic case, this Br2 production process is important for the PG budget in the upper troposphere and in the TTL above convective systems. This process is favoured by acidic conditions in the cloud droplets, i.e. polluted conditions. In the case of low bromoform initial mixing ratios, which are more representative of the mean distribution in the tropics, this Br2 production process is shown to be less important. These conclusions could nevertheless be revisited if the knowledge of chlorine and bromine chemistry in the cloud droplets was improved in the future.

An Important Armenian MS. with Greek Miniatures

1942 ◽  
Vol 74 (3-4) ◽  
pp. 155-162
Author(s):  
H. Kurdian
Keyword(s):  
New York ◽  
New York City ◽  
York City ◽  
Christian Iconography

In 1941 while in New York City I was fortunate enough to purchase an Armenian MS. which I believe will be of interest to students of Eastern Christian iconography.

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