scholarly journals Development and application of a new mobile LOPAP instrument for the measurement of HONO altitude profiles in the planetary boundary layer

2009 ◽  
Vol 2 (4) ◽  
pp. 2027-2054 ◽  
Author(s):  
R. Häseler ◽  
T. Brauers ◽  
F. Holland ◽  
A. Wahner
Keyword(s):  
Nitrous Acid ◽  
Ground Level ◽  
Concentration Profiles ◽  
Mixing Ratio ◽  
Above Ground Level ◽  
Mixing Ratios ◽  
New Instrument ◽  
Mobile Measurements ◽  
Southwest Germany ◽  
Absorption Technique

Abstract. The LOPAP (long path absorption) technique has been shown to be very sensitive for the detection of nitrous acid (HONO) in the atmosphere. However, current instruments were mainly built for ground based applications. Therefore, we designed a new LOPAP instrument to be more versatile for mobile measurements and to meet the requirements for airborne application. The detection limit of the new instrument is below 1 ppt at a time resolution of 5 to 7 min. As a first test, the instrument was successfully employed during the ZEPTER-1 campaign in July 2007 on board of the Zeppelin NT airship. During 15 flights on six days we measured HONO concentration profiles over southwest Germany, predominantly in the range between 100 m and 650 m above ground level. On average, a mixing ratio of 34 ppt was observed, almost independently of height. Within a econd campaign, ZEPTER-2 in fall 2008, higher HONO mixing ratios were observed in the Lake Constance area.

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.

Corrigendum to: Atmospheric variation of nitrous acid at different sites in Europe

2007 ◽  
Vol 4 (5) ◽  
pp. 364 ◽  
Author(s):  
Karin Acker ◽  
Detlev Möller
Keyword(s):  
Hydroxyl Radical ◽  
Nitrous Acid ◽  
Field Experiments ◽  
Early Morning ◽  
Mixing Ratio ◽  
Gas Phase Reactions ◽  
Sources And Sinks ◽  
Mixing Ratios ◽  
Secondary Pollutants ◽  
Rural Sites

Environmental context. Nitrous acid (HNO2) is an important source of the hydroxyl radical (OH.), the most important daytime oxidising species that contributes to the formation of ozone as well as of other secondary pollutants in the troposphere. Understanding the sources and sinks of HNO2 is of crucial interest for accurately modelling the chemical composition of the troposphere and predicting future trace gas concentrations. Abstract. Nitrous acid and several other atmospheric components and variables were continuously measured during complex field experiments at seven different suburban and rural sites in Europe. HNO2 is mainly formed by heterogeneous processes and is often accumulated in the nighttime boundary layer. Our results confirm that the photolysis of HNO2 is an important source of the hydroxyl radical, not only in the early morning hours but also throughout the entire day, and is often comparable with the contribution of ozone and formaldehyde photolysis. At all research sites unexpectedly high HNO2 mixing ratios were observed during the daytime (up to several hundred ppt, or pmol mol-1). Moreover, surprisingly, the HNO2 mixing ratio at the three mountain sites often showed a broad maximum or several distinct peaks at midday and lower mixing ratios during the night. Assuming a quickly established photo-equilibrium between the known significant gas phase reactions, only a few ppt HNO2 should be present around noon. The ratio of known sources to sinks indicates a missing daytime HNO2 source of 160-2600 ppt h-1 to make up the balance. Based on these values and on production mechanisms proposed in the literature we hypothesise that the daytime mixing ratio levels may only be explained by a fast electron transfer onto adsorbed NO2.

Atmospheric variation of nitrous acid at different sites in Europe

2007 ◽  
Vol 4 (4) ◽  
pp. 242 ◽  
Author(s):  
Karin Acker ◽  
Detlev Möller
Keyword(s):  
Hydroxyl Radical ◽  
Nitrous Acid ◽  
Field Experiments ◽  
Early Morning ◽  
Mixing Ratio ◽  
Gas Phase Reactions ◽  
Sources And Sinks ◽  
Mixing Ratios ◽  
Secondary Pollutants ◽  
Rural Sites

Environmental context. Nitrous acid (HNO2) is an important source of the hydroxyl radical (OH•), the most important daytime oxidising species that contributes to the formation of ozone as well as of other secondary pollutants in the troposphere. Understanding the sources and sinks of HNO2 is of crucial interest for accurately modelling the chemical composition of the troposphere and predicting future trace gas concentrations. Abstract. Nitrous acid and several other atmospheric components and variables were continuously measured during complex field experiments at seven different suburban and rural sites in Europe. HNO2 is mainly formed by heterogeneous processes and is often accumulated in the nighttime boundary layer. Our results confirm that the photolysis of HNO2 is an important source of the hydroxyl radical, not only in the early morning hours but also throughout the entire day, and is often comparable with the contribution of ozone and formaldehyde photolysis. At all research sites unexpectedly high HNO2 mixing ratios were observed during the daytime (up to several hundred ppt, or pmol mol–1). Moreover, surprisingly, the HNO2 mixing ratio at the three mountain sites often showed a broad maximum or several distinct peaks at midday and lower mixing ratios during the night. Assuming a quickly established photo-equilibrium between the known significant gas phase reactions, only a few ppt HNO2 should be present around noon. The ratio of known sources to sinks indicates a missing daytime HNO2 source of 160–2600 ppt h–1 to make up the balance. Based on these values and on production mechanisms proposed in the literature we hypothesise that the daytime mixing ratio levels may only be explained by a fast electron transfer onto adsorbed NO2.

scholarly journals Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow?

2014 ◽  
Vol 14 (18) ◽  
pp. 9963-9976 ◽  
Author(s):  
M. Legrand ◽  
S. Preunkert ◽  
M. Frey ◽  
Th. Bartels-Rausch ◽  
A. Kukui ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Austral Summer ◽  
Vertical Gradient ◽  
No Oxidation ◽  
Local Source ◽  
Mixing Ratio ◽  
Model Calculations ◽  
Antarctic Plateau ◽  
Mixing Ratios ◽  
Surface Snow

Abstract. During the austral summer 2011/2012 atmospheric nitrous acid (HONO) was investigated for the second time at the Concordia site (75°06' S, 123°33' E), located on the East Antarctic Plateau, by deploying a long-path absorption photometer (LOPAP). Hourly mixing ratios of HONO measured in December 2011/January 2012 (35 ± 5.0 pptv) were similar to those measured in December 2010/January 2011 (30.4 ± 3.5 pptv). The large value of the HONO mixing ratio at the remote Concordia site suggests a local source of HONO in addition to weak production from oxidation of NO by the OH radical. Laboratory experiments demonstrate that surface snow removed from Concordia can produce gas-phase HONO at mixing ratios half that of the NOx mixing ratio produced in the same experiment at typical temperatures encountered at Concordia in summer. Using these lab data and the emission flux of NOx from snow estimated from the vertical gradient of atmospheric concentrations measured during the campaign, a mean diurnal HONO snow emission ranging between 0.5 and 0.8 × 109 molecules cm−2 s−1 is calculated. Model calculations indicate that, in addition to around 1.2 pptv of HONO produced by the NO oxidation, these HONO snow emissions can only explain 6.5 to 10.5 pptv of HONO in the atmosphere at Concordia. To explain the difference between observed and simulated HONO mixing ratios, tests were done both in the field and at lab to explore the possibility that the presence of HNO4 had biased the measurements of HONO.

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 Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic plateau) in summer: a strong source from surface snow?

2014 ◽  
Vol 14 (8) ◽  
pp. 11749-11785 ◽  
Author(s):  
M. Legrand ◽  
S. Preunkert ◽  
M. Frey ◽  
T. Bartels-Rausch ◽  
A. Kukui ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Austral Summer ◽  
Vertical Gradient ◽  
No Oxidation ◽  
Local Source ◽  
Mixing Ratio ◽  
Model Calculations ◽  
Antarctic Plateau ◽  
Mixing Ratios ◽  
Surface Snow

Abstract. During the austral summer 2011/2012 atmospheric nitrous acid was investigated for the second time at the Concordia site (75°06' S, 123°33' E) located on the East Antarctic plateau by deploying a long path absorption photometer (LOPAP). Hourly mixing ratios of HONO measured in December 2011/January 2012 (35 ± 5.0 pptv) were similar to those measured in December 2010/January 2011 (30.4 ± 3.5 pptv). The large value of the HONO mixing ratio at the remote Concordia site suggests a local source of HONO in addition to weak production from oxidation of NO by the OH radical. Laboratory experiments demonstrate that surface snow removed from Concordia can produce gas phase HONO at mixing ratios half that of NOx mixing ratio produced in the same experiment at typical temperatures encountered at Concordia in summer. Using these lab data and the emission flux of NOx from snow estimated from the vertical gradient of atmospheric concentrations measured during the campaign, a mean diurnal HONO snow emission ranging between 0.5 and 0.8 × 109 molecules cm−2 s−1 is calculated. Model calculations indicate that, in addition to around 1.2 pptv of HONO produced by the NO oxidation, these HONO snow emissions can only explain 6.5 to 10.5 pptv of HONO in the atmosphere at Concordia. To explain the difference between observed and simulated HONO mixing ratios, tests were done both in the field and at lab to explore the possibility that the presence of HNO4 had biased the measurements of HONO.

scholarly journals Spatial Analysis (Measurements at Heights of 10 m and 20 m above Ground Level) of the Concentrations of Particulate Matter (PM10, PM2.5, and PM1.0) and Gaseous Pollutants (H2S) on the University Campus: A Case Study

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Robert Cichowicz ◽  
Maciej Dobrzański
Keyword(s):  
Spatial Distribution ◽  
Hydrogen Sulfide ◽  
Particulate Matter ◽  
Air Quality ◽  
Spatial Analysis ◽  
Ground Level ◽  
Leeward Side ◽  
High Concentration ◽  
Above Ground Level ◽  
High Concentrations

Spatial analysis of the distribution of particulate matter PM10, PM2.5, PM1.0, and hydrogen sulfide (H2S) gas pollution was performed in the area around a university library building. The reasons for the subject matter were reports related to the perceptible odor characteristic of hydrogen sulfide and a general poor assessment of air quality by employees and students. Due to the area of analysis, it was decided to perform measurements at two heights, 10 m and 20 m above ground level, using measuring equipment attached to a DJI Matrice 600 unmanned aerial vehicle (UAV). The aim of the measurements was air quality assessment and investigate the convergence of the theory of air flow around the building with the spatial distribution of air pollutants. Considerable differences of up to 63% were observed in the concentrations of pollutants measured around the building, especially between opposite sides, depending on the direction of the wind. To explain these differences, the theory of aerodynamics was applied to visualize the probable airflow in the direction of the wind. A strong convergence was observed between the aerodynamic model and the spatial distribution of pollutants. This was evidenced by the high concentrations of dust in the areas of strong turbulence at the edges of the building and on the leeward side. The accumulation of pollutants was also clearly noticeable in these locations. A high concentration of H2S was recorded around the library building on the side of the car park. On the other hand, the air turbulence around the building dispersed the gas pollution, causing the concentration of H2S to drop on the leeward side. It was confirmed that in some analyzed areas the permissible concentration of H2S was exceeded.

scholarly journals Assessment of Tropospheric Concentrations of NO2 from the TROPOMI/Sentinel-5 Precursor for the Estimation of Long-Term Exposure to Surface NO2 over South Korea

2021 ◽  
Vol 13 (10) ◽  
pp. 1877
Author(s):  
Ukkyo Jeong ◽  
Hyunkee Hong
Keyword(s):  
South Korea ◽  
Spatial Resolution ◽  
Atmospheric Composition ◽  
Mixing Ratio ◽  
Mean Values ◽  
Mixing Ratios ◽  
Tropospheric No2 ◽  
Korean Ministry ◽  
Surface Mixing ◽  
Rural Sites

Since April 2018, the TROPOspheric Monitoring Instrument (TROPOMI) has provided data on tropospheric NO2 column concentrations (CTROPOMI) with unprecedented spatial resolution. This study aims to assess the capability of TROPOMI to acquire high spatial resolution data regarding surface NO2 mixing ratios. In general, the instrument effectively detected major and moderate sources of NO2 over South Korea with a clear weekday–weekend distinction. We compared the CTROPOMI with surface NO2 mixing ratio measurements from an extensive ground-based network over South Korea operated by the Korean Ministry of Environment (SKME; more than 570 sites), for 2019. Spatiotemporally collocated CTROPOMI and SKME showed a moderate correlation (correlation coefficient, r = 0.67), whereas their annual mean values at each site showed a higher correlation (r = 0.84). The CTROPOMI and SKME were well correlated around the Seoul metropolitan area, where significant amounts of NO2 prevailed throughout the year, whereas they showed lower correlation at rural sites. We converted the tropospheric NO2 from TROPOMI to the surface mixing ratio (STROPOMI) using the EAC4 (ECMWF Atmospheric Composition Reanalysis 4) profile shape, for quantitative comparison with the SKME. The estimated STROPOMI generally underestimated the in-situ value obtained, SKME (slope = 0.64), as reported in previous studies.

scholarly journals A Climatology of Nocturnal Low-Level Jets at Cabauw

2009 ◽  
Vol 48 (8) ◽  
pp. 1627-1642 ◽  
Author(s):  
P. Baas ◽  
F. C. Bosveld ◽  
H. Klein Baltink ◽  
A. A. M. Holtslag
Keyword(s):  
Wind Speed ◽  
Ground Level ◽  
Geostrophic Wind ◽  
Stable Stratification ◽  
Radiative Cooling ◽  
Inertial Oscillation ◽  
Stable Boundary Layers ◽  
Above Ground Level ◽  
Low Level ◽  
Low Level Jets

Abstract A climatology of nocturnal low-level jets (LLJs) is presented for the topographically flat measurement site at Cabauw, the Netherlands. LLJ characteristics are derived from a 7-yr half-hourly database of wind speed profiles, obtained from the 200-m mast and a wind profiler. Many LLJs at Cabauw originate from an inertial oscillation, which develops after sunset in a layer decoupled from the surface by stable stratification. The data are classified to different types of stable boundary layers by using the geostrophic wind speed and the isothermal net radiative cooling as classification parameters. For each of these classes, LLJ characteristics like frequency of occurrence, height above ground level, and the turning of the wind vector across the boundary layer are determined. It is found that LLJs occur in about 20% of the nights, are typically situated at 140–260 m above ground level, and have a speed of 6–10 m s−1. Development of a substantial LLJ is most likely to occur for moderate geostrophic forcing and a high radiative cooling. A comparison with the 40-yr ECMWF Re-Analysis (ERA-40) is added to illustrate how the results can be used to evaluate the performance of atmospheric models.

scholarly journals One-Year Characterization and Reactivity of Isoprene and Its Impact on Surface Ozone Formation at A Suburban Site in Guangzhou, China

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 201 ◽  
Author(s):  
Yu Zou ◽  
Xue Jiao Deng ◽  
Tao Deng ◽  
Chang Qin Yin ◽  
Fei Li
Keyword(s):  
Surface Ozone ◽  
Atmospheric Composition ◽  
Anthropogenic Factors ◽  
Mixing Ratio ◽  
Night Time ◽  
Subtropical Zone ◽  
Guangzhou City ◽  
Mixing Ratios ◽  
One Year ◽  
Suburban Site

Isoprene has a potentially large effect on ozone (O3) formation in the subtropical, highly polluted city of Guangzhou. Online measurements of isoprene in Guangzhou city are scarce; thus, isoprene levels were monitored for one year at the Guangzhou Panyu Atmospheric Composition Station (GPACS), a suburban site in Guangzhou, using an online gas chromatography-flame ionization detector (GC–FID) system to investigate the characterization and reactivity of isoprene and its effect on the O3 peak profile in different seasons. The results showed that the daily average mixing ratios of isoprene at GPACS were 0.40, 2.20, 1.40, and 0.13 mixing ratio by volume (ppbv) in spring, summer, autumn, and winter, respectively. These values were considerably higher than the mixing ratios of isoprene in the numerous other subtropical and temperate cities around the world. Furthermore, isoprene ranked first with regard to O3 formation potential (OFP) and propylene-equivalent mixing ratio among 56 measured non–methane hydrocarbons (NMHCs). The ratios of isoprene to cis-2-butene, an exhaust tracer, were determined to estimate the fractions of biogenic and anthropogenic emissions. The results revealed a much greater contribution from biogenic than anthropogenic factors during the daytime in all four seasons. In addition, night-time isoprene emissions were mostly associated with vehicles in winter, and the residual isoprene that remained after photochemical loss during the daytime also persisted into the night. The high levels of isoprene in summer and autumn may cause the strong and broad peaks of the O3 profile because of its association with the most favorable meteorological conditions (e.g., high temperature and intense solar radiation) and the highest OH mixing ratio, which could affect human health by exposing people to a high O3 mixing ratio for prolonged periods. The lower mixing ratios of isoprene resulted in a weak and sharp peak in the O3 profile in both spring and winter. The high level of isoprene in the subtropical zone could accentuate its large impact on atmospheric oxidant capacity and air quality in Guangzhou city.

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