Long-term MAX-DOAS measurements of formaldehyde in the suburban area of London 

2021 ◽  
Author(s):  
Sebastian Donner ◽  
Steffen Dörner ◽  
Joelle Buxmann ◽  
Steffen Beirle ◽  
David Campbell ◽  
...  
Keyword(s):  
Trace Gases ◽  
Lower Troposphere ◽  
Anthropogenic Pollution ◽  
Tropospheric Chemistry ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Pollution Levels ◽  
Measurement Site ◽  
Prevailing Wind Direction

<p>Multi-AXis (MAX)-Differential Optical Absorption Spectroscopy (DOAS) instruments record spectra of scattered sun light under different elevation angles. From such measurements tropospheric vertical column densities (VCDs) and vertical profiles of different atmospheric trace gases and aerosols can be determined for the lower troposphere. These measurements allow a simultaneous observation of multiple trace gases, e.g. formaldehyde (HCHO), glyoxal (CHOCHO) and nitrogen dioxide (NO<sub>2</sub>), with the same measurement setup. Since November 2018, a MAX-DOAS instrument has been operating at Bayfordbury Observatory, which is located approximately 30 km north of London. This measurement site is operated by the University of Hertfordshire and equipped with an AERONET station, a LIDAR and multiple instruments to measure meteorological quantities and solar radiation. Depending on the prevailing wind direction the air masses at the measurement site can be dominated by the pollution of London (SE to SW winds) or rather pristine air (northerly winds).</p><p>First results already showed that the highest formaldehyde and glyoxal columns are observed for southerly to southeasterly winds indicating the influence of the anthropogenic emissions of London. However, the detailed patterns of the different trace gases were found to be more complex. Therefore, this measurement site is well suited to study the influence of anthropogenic pollution on the atmospheric composition and chemistry at a rather pristine location in the vicinity of London, a major European capital with about 10 million inhabitants and 4 major international airports.</p><p>In this study, trace gas and aerosol profiles are retrieved using the MAinz Profile Algorithm (MAPA) with a focus on tropospheric HCHO which plays an important role in tropospheric chemistry. The HCHO results are combined with the results of other trace species such as NO<sub>2</sub>, CHOCHO and aerosols in order to identify pollution levels, emission sources and different chemical regimes.</p>

One year of MAX-DOAS measurements of tropospheric trace gases and aerosols in the suburban area of London

2020 ◽  
Author(s):  
Sebastian Donner ◽  
Steffen Dörner ◽  
Joelle Buxmann ◽  
Steffen Beirle ◽  
David Campbell ◽  
...  
Keyword(s):  
Trace Gases ◽  
Lower Troposphere ◽  
Anthropogenic Pollution ◽  
Tropospheric Chemistry ◽  
Atmospheric Composition ◽  
Vertical Column ◽  
Pollution Levels ◽  
Measurement Site ◽  
Trace Species ◽  
Prevailing Wind Direction

<p>Multi-AXis (MAX)-DOAS instruments record spectra of scattered sun light under different elevation angles. From such measurements tropospheric vertical column densities (VCDs) and vertical profiles of different atmospheric trace gases and aerosols can be determined for the lower troposphere. These measurements allow a simultaneous observation of multiple trace gases (e.g. HCHO, CHOCHO, NO<sub>2</sub>, etc.) with the same measurement setup. Since November 2018, a MAX-DOAS instrument is operated at the Bayfordbury Observatory, which is located approximately 30 km north of London. This measurement site is operated by the University of Hertfordshire and equipped with an AERONET station, a LIDAR and multiple instruments to measure meteorological quantities and solar radiation. Depending on the prevailing wind direction the air masses at the measurement site can be dominated by the pollution of London (SE to SW winds) or rather pristine air (northerly winds). Therefore, this measurement site is well suited to study the influence of anthropogenic pollution on the atmospheric composition and chemistry at a rather pristine location in the vicinity of London, a major European capital with 9.8 million inhabitants and 4 major international airports.</p><p>In this study, trace gas and aerosol profiles are retrieved using the MAinz Profile Algorithm MAPA (Beirle et al., 2018) with a focus on tropospheric formaldehyde (HCHO) which plays an important role in tropospheric chemistry. The HCHO results are combined with the results of other trace species such as NO<sub>2</sub>, CHOCHO and aerosols in order to identify different chemical regimes and pollution levels.</p>

scholarly journals MAX-DOAS measurements of NO<sub>2</sub>, SO<sub>2</sub>, HCHO, and BrO at the Mt. Waliguan WMO GAW global baseline station in the Tibetan Plateau

2020 ◽  
Vol 20 (11) ◽  
pp. 6973-6990 ◽  
Author(s):  
Jianzhong Ma ◽  
Steffen Dörner ◽  
Sebastian Donner ◽  
Junli Jin ◽  
Siyang Cheng ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Trace Gases ◽  
Elevation Angle ◽  
Lower Troposphere ◽  
Statistical Error ◽  
Tropospheric Chemistry ◽  
Ozone Production ◽  
Optical Absorption Spectroscopy ◽  
The Tibetan Plateau ◽  
Mixing Ratios

Abstract. Mt. Waliguan Observatory (WLG) is a World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) global baseline station in China. WLG is located at the northeastern part of the Tibetan Plateau (36∘17′ N, 100∘54′ E, 3816 m a.s.l.) and is representative of the pristine atmosphere over the Eurasian continent. We made long-term ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements at WLG during the period 2012–2015. In this study, we retrieve the differential slant column densities (dSCDs) and estimate the tropospheric background mixing ratios of different trace gases, including NO2, SO2, HCHO, and BrO, using the measured spectra at WLG. Averaging of 10 original spectra is found to be an “optimum option” for reducing both the statistical error of the spectral retrieval and systematic errors in the analysis. The dSCDs of NO2, SO2, HCHO, and BrO under clear-sky and low-aerosol-load conditions are extracted from measured spectra at different elevation angles at WLG. By performing radiative transfer simulations with the model TRACY-2, we establish approximate relationships between the trace gas dSCDs at 1∘ elevation angle and the corresponding average tropospheric background volume mixing ratios. Mixing ratios of these trace gases in the lower troposphere over WLG are estimated to be in a range of about 7 ppt (January) to 100 ppt (May) for NO2, below 0.5 ppb for SO2, between 0.4 and 0.9 ppb for HCHO, and lower than 0.3 ppt for BrO. The chemical box model simulations constrained by the NO2 concentration from our MAX-DOAS measurements show that there is a little net ozone loss (−0.8 ppb d−1) for the free-tropospheric conditions and a little net ozone production (0.3 ppb d−1) for the boundary layer conditions over WLG during summertime. Our study provides valuable information and data sets for further investigating tropospheric chemistry in the background atmosphere and its links to anthropogenic activities.

scholarly journals The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) and its operations from an unmanned aerial vehicle (UAV) during the AROMAT campaign

2018 ◽  
Vol 11 (1) ◽  
pp. 551-567 ◽  
Author(s):  
Alexis Merlaud ◽  
Frederik Tack ◽  
Daniel Constantin ◽  
Lucian Georgescu ◽  
Jeroen Maes ◽  
...  
Keyword(s):  
Water Vapour ◽  
Unmanned Aerial Vehicle ◽  
Trace Gases ◽  
Unmanned Aircraft ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Large Power ◽  
Aerial Vehicle ◽  
Composition Monitoring

Abstract. The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) is a compact remote sensing instrument dedicated to mapping trace gases from an unmanned aerial vehicle (UAV). SWING is based on a compact visible spectrometer and a scanning mirror to collect scattered sunlight. Its weight, size, and power consumption are respectively 920 g, 27 cm × 12 cm × 8 cm, and 6 W. SWING was developed in parallel with a 2.5 m flying-wing UAV. This unmanned aircraft is electrically powered, has a typical airspeed of 100 km h−1, and can operate at a maximum altitude of 3 km. We present SWING-UAV experiments performed in Romania on 11 September 2014 during the Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign, which was dedicated to test newly developed instruments in the context of air quality satellite validation. The UAV was operated up to 700 m above ground, in the vicinity of the large power plant of Turceni (44.67∘ N, 23.41∘ E; 116 ma.s.l.). These SWING-UAV flights were coincident with another airborne experiment using the Airborne imaging differential optical absorption spectroscopy (DOAS) instrument for Measurements of Atmospheric Pollution (AirMAP), and with ground-based DOAS, lidar, and balloon-borne in situ observations. The spectra recorded during the SWING-UAV flights are analysed with the DOAS technique. This analysis reveals NO2 differential slant column densities (DSCDs) up to 13±0.6×1016 molec cm−2. These NO2 DSCDs are converted to vertical column densities (VCDs) by estimating air mass factors. The resulting NO2 VCDs are up to 4.7±0.4×1016 molec cm−2. The water vapour DSCD measurements, up to 8±0.15×1022 molec cm−2, are used to estimate a volume mixing ratio of water vapour in the boundary layer of 0.013±0.002 mol mol−1. These geophysical quantities are validated with the coincident measurements.

scholarly journals The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) and its operations from an Unmanned Aerial Vehicle (UAV) during the AROMAT campaign

2017 ◽  
Author(s):  
Alexis Merlaud ◽  
Frederik Tack ◽  
Daniel Constantin ◽  
Lucian Georgescu ◽  
Jeroen Maes ◽  
...  
Keyword(s):  
Water Vapor ◽  
Unmanned Aerial Vehicle ◽  
Trace Gases ◽  
Unmanned Aircraft ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Large Power ◽  
Aerial Vehicle ◽  
Composition Monitoring

Abstract. The Small Whiskbroom Imager for atmospheric compositioN monitorinG (SWING) is a compact remote sensing instrument dedicated to mapping trace gases from an Unmanned Aerial Vehicle (UAV). SWING is based on a compact visible spectrometer and a scanning mirror to collect scattered sunlight. Its weight, size, and power consumption are respectively 920 g, 27 x 12 x 8 cm3, and 6 W. SWING was developed in parallel with a 2.5 m flying wing UAV. This unmanned aircraft is electrically powered, has a typical airspeed of 100 km h−1, and can operate at a maximum altitude of 3 km. We present SWING-UAV experiments performed in Romania on 11 September 2014 during the Airborne ROmanian Measurements of Aerosols and Trace gases (AROMAT) campaign. The UAV was operated up to 700 m above ground, in the vicinity of the large power plant of Turceni (44.67° N, 23.41° E, 116 m a.s.l.). These SWING-UAV flights were coincident with another airborne experiment using the Airborne imaging Differential Optical Absorption Spectroscopy (DOAS) instrument for Measurements of Atmospheric Pollution (AirMAP), and with ground-based DOAS, lidar, and balloone-borne in-situ observations. The spectra recorded during the SWING-UAV flights are analyzed with the DOAS technique. This analysis reveals NO2 differential slant column densities (DSCDs) up to 13 &amp;pm; 0.6 x 1016 molec cm−2. These NO2 DSCDs are converted to vertical column densities (VCDs) by estimating air mass factors. The resulting NO2 VCDs are up to 4.7 &amp;pm; 0.4 x 1016 molec cm−2. The water vapor DSCD measurements, up to 8 &amp;pm; 0.15 x 1022 molec cm−2, are used to estimate a volume mixing ratio of water vapor in the boundary layer of 0.013 &amp;pm; 0.002 mol mol−1. These geophysical quantities are validated with the coincident measurements.

scholarly journals Recommendations for HCHO and SO2 Retrieval Settings from MAX-DOAS Observations under Different Meteorological Conditions

2021 ◽  
Vol 13 (12) ◽  
pp. 2244
Author(s):  
Zeeshan Javed ◽  
Aimon Tanvir ◽  
Muhammad Bilal ◽  
Wenjing Su ◽  
Congzi Xia ◽  
...  
Keyword(s):  
Column Density ◽  
Trace Gases ◽  
Meteorological Conditions ◽  
Optical Absorption Spectroscopy ◽  
Chemical Production ◽  
Vertical Column ◽  
Phase Oxidation ◽  
Fog Days ◽  
Rms Errors ◽  
Optimal Settings

Recently, the occurrence of fog and haze over China has increased. The retrieval of trace gases from the multi-axis differential optical absorption spectroscopy (MAX-DOAS) is challenging under these conditions. In this study, various reported retrieval settings for formaldehyde (HCHO) and sulfur dioxide (SO2) are compared to evaluate the performance of these settings under different meteorological conditions (clear day, haze, and fog). The dataset from 1st December 2019 to 31st March 2020 over Nanjing, China, is used in this study. The results indicated that for HCHO, the optimal settings were in the 324.5–359 nm wavelength window with a polynomial order of five. At these settings, the fitting and root mean squared (RMS) errors for column density were considerably improved for haze and fog conditions, and the differential slant column densities (DSCDs) showed more accurate values compared to the DSCDs between 336.5 and 359 nm. For SO2, the optimal settings for retrieval were found to be at 307–328 nm with a polynomial order of five. Here, root mean square (RMS) and fitting errors were significantly lower under all conditions. The observed HCHO and SO2 vertical column densities were significantly lower on fog days compared to clear days, reflecting a decreased chemical production of HCHO and aqueous phase oxidation of SO2 in fog droplets.

scholarly journals Tropospheric nitrogen dioxide column retrieval from ground-based zenith–sky DOAS observations

2015 ◽  
Vol 8 (6) ◽  
pp. 2417-2435 ◽  
Author(s):  
F. Tack ◽  
F. Hendrick ◽  
F. Goutail ◽  
C. Fayt ◽  
A. Merlaud ◽  
...  
Keyword(s):  
Nitrogen Dioxide ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Retrieval Algorithm ◽  
Measuring Instruments ◽  
Reference Spectrum ◽  
Vertical Column ◽  
Data Set ◽  
Residual Amount

Abstract. We present an algorithm for retrieving tropospheric nitrogen dioxide (NO2) vertical column densities (VCDs) from ground-based zenith–sky (ZS) measurements of scattered sunlight. The method is based on a four-step approach consisting of (1) the differential optical absorption spectroscopy (DOAS) analysis of ZS radiance spectra using a fixed reference spectrum corresponding to low NO2 absorption, (2) the determination of the residual amount in the reference spectrum using a Langley-plot-type method, (3) the removal of the stratospheric content from the daytime total measured slant column based on stratospheric VCDs measured at sunrise and sunset, and simulation of the rapid NO2 diurnal variation, (4) the retrieval of tropospheric VCDs by dividing the resulting tropospheric slant columns by appropriate air mass factors (AMFs). These steps are fully characterized and recommendations are given for each of them. The retrieval algorithm is applied on a ZS data set acquired with a multi-axis (MAX-) DOAS instrument during the Cabauw (51.97° N, 4.93° E, sea level) Intercomparison campaign for Nitrogen Dioxide measuring Instruments (CINDI) held from 10 June to 21 July 2009 in the Netherlands. A median value of 7.9 × 1015 molec cm−2 is found for the retrieved tropospheric NO2 VCDs, with maxima up to 6.0 × 1016 molec cm−2. The error budget assessment indicates that the overall error σTVCD on the column values is less than 28%. In the case of low tropospheric contribution, σTVCD is estimated to be around 39% and is dominated by uncertainties in the determination of the residual amount in the reference spectrum. For strong tropospheric pollution events, σTVCD drops to approximately 22% with the largest uncertainties on the determination of the stratospheric NO2 abundance and tropospheric AMFs. The tropospheric VCD amounts derived from ZS observations are compared to VCDs retrieved from off-axis and direct-sun measurements of the same MAX-DOAS instrument as well as to data from a co-located Système d'Analyse par Observations Zénithales (SAOZ) spectrometer. The retrieved tropospheric VCDs are in good agreement with the different data sets with correlation coefficients and slopes close to or larger than 0.9. The potential of the presented ZS retrieval algorithm is further demonstrated by its successful application on a 2-year data set, acquired at the NDACC (Network for the Detection of Atmospheric Composition Change) station Observatoire de Haute Provence (OHP; Southern France).

scholarly journals Technical note: Evaluation of profile retrievals of aerosols and trace gases for MAX-DOAS measurements under different aerosol scenarios based on radiative transfer simulations

2021 ◽  
Vol 21 (17) ◽  
pp. 12867-12894
Author(s):  
Xin Tian ◽  
Yang Wang ◽  
Steffen Beirle ◽  
Pinhua Xie ◽  
Thomas Wagner ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Trace Gases ◽  
Optimal Estimation ◽  
Estimation Algorithm ◽  
Optical Absorption Spectroscopy ◽  
Limited Information ◽  
Inversion Algorithm ◽  
Vertical Column ◽  
Near Surface ◽  
Aerosol Pollution

Abstract. Ground-based Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) is a state-of-the-art remote sensing technique for deriving vertical profiles of trace gases and aerosols. However, MAX-DOAS profile inversions under aerosol pollution scenarios are challenging because of the complex radiative transfer and limited information content of the measurements. In this study, the performances of two inversion algorithms were evaluated for various aerosol pollution scenarios based on synthetic slant column densities (SCDs) derived from radiative transfer simulations. Compared to previous studies, in our study, much larger ranges of aerosol optical depth (AOD) and NO2 vertical column densities (VCDs) are covered. One inversion algorithm is based on optimal estimation; the other uses a parameterized approach. In this analysis, three types of profile shapes for aerosols and NO2 were considered: exponential, Boltzmann, and Gaussian. First, the systematic deviations of the retrieved aerosol profiles from the input profiles were investigated. For most cases, the AODs of the retrieved profiles were found to be systematically lower than the input values, and the deviations increased with increasing AOD. In particular for the optimal estimation algorithm and for high AOD, these findings are consistent with the results in previous studies. The assumed single scattering albedo (SSA) and asymmetry parameter (AP) have a systematic influence on the aerosol retrieval. However, for most cases the influence of the assumed SSA and AP on the retrieval results are rather small (compared to other uncertainties). For the optimal estimation algorithm, the agreement with the input values can be improved by optimizing the covariance matrix of the a priori uncertainties. Second, the aerosol effects on the NO2 profile retrieval were tested. Here, especially for the optimal estimation algorithm, a systematic dependence on the NO2 VCD was found, with a strong relative overestimation of the retrieved results for low NO2 VCDs and an underestimation for high NO2 VCDs. In contrast, the dependence on the aerosol profiles was found to be rather low. Interestingly, the results for both investigated wavelengths (360 and 477 nm) were found to be rather similar, indicating that the differences in the radiative transfer between both wavelengths have no strong effect. In general, both inversion schemes can retrieve the near-surface values of aerosol extinction and trace gas concentrations well.

scholarly journals Direct observation of two dimensional trace gas distribution with an airborne Imaging DOAS instrument

2008 ◽  
Vol 8 (3) ◽  
pp. 11879-11907 ◽  
Author(s):  
K.-P. Heue ◽  
T. Wagner ◽  
S. P. Broccardo ◽  
D. Walter ◽  
S. J. Piketh ◽  
...  
Keyword(s):  
Power Plants ◽  
Trace Gases ◽  
Tropospheric Chemistry ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Small Scale ◽  
Two Dimensional ◽  
Gas Distribution ◽  
Dimensional Distribution ◽  
Airborne Imaging

Abstract. In many investigations of tropospheric chemistry information about the two dimensional distribution of trace gases on a small scale (e.g. tens to hundreds of meters) is highly desirable. An airborne instrument based on imaging Differential Optical Absorption Spectroscopy has been built to map the 2-D distribution of a series of relevant trace gases including NO2, HCHO, C2H2O2, H2O, O4, SO2, and BrO on a scale of 100 m. Here we report on the first tests of the novel aircraft instrument over the industrialised South African Highveld, where large variations in NO2 column densities in the immediate vicinity of several sources e.g. power plants or steel works, were measured. The observed patterns in the trace gas distribution are interpreted with respect to flux estimates, and it is seen that the fine resolution of the measurements allows separate sources in close proximity to one another to be distinguished.

scholarly journals Validation of Aura-OMI QA4ECV NO<sub>2</sub> climate data records with ground-based DOAS networks: the role of measurement and comparison uncertainties

2020 ◽  
Vol 20 (13) ◽  
pp. 8017-8045 ◽  
Author(s):  
Steven Compernolle ◽  
Tijl Verhoelst ◽  
Gaia Pinardi ◽  
José Granville ◽  
Daan Hubert ◽  
...  
Keyword(s):  
Scattered Light ◽  
A Priori ◽  
Sampling Bias ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Climate Data ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Standard Data ◽  
The Difference

Abstract. The QA4ECV (Quality Assurance for Essential Climate Variables) version 1.1 stratospheric and tropospheric NO2 vertical column density (VCD) climate data records (CDRs) from the OMI (Ozone Monitoring Instrument) satellite sensor are validated using NDACC (Network for the Detection of Atmospheric Composition Change) zenith-scattered light differential optical absorption spectroscopy (ZSL-DOAS) and multi-axis DOAS (MAX-DOAS) data as a reference. The QA4ECV OMI stratospheric VCDs have a small bias of ∼0.2 Pmolec.cm-2 (5 %–10 %) and a dispersion of 0.2 to 1 Pmolec.cm-2 with respect to the ZSL-DOAS measurements. QA4ECV tropospheric VCD observations from OMI are restricted to near-cloud-free scenes, leading to a negative sampling bias (with respect to the unrestricted scene ensemble) of a few peta molecules per square centimetre (Pmolec.cm-2) up to −10 Pmolec.cm-2 (−40 %) in one extreme high-pollution case. The QA4ECV OMI tropospheric VCD has a negative bias with respect to the MAX-DOAS data (−1 to −4 Pmolec.cm-2), which is a feature also found for the OMI OMNO2 standard data product. The tropospheric VCD discrepancies between satellite measurements and ground-based data greatly exceed the combined measurement uncertainties. Depending on the site, part of the discrepancy can be attributed to a combination of comparison errors (notably horizontal smoothing difference error), measurement/retrieval errors related to clouds and aerosols, and the difference in vertical smoothing and a priori profile assumptions.

Quantification of Nitrogen Dioxide and Sulfur Dioxide emissions from Bucharest using a mobile-DOAS setup

2020 ◽  
Author(s):  
Sebastian Iancu
Keyword(s):  
Sulfur Dioxide ◽  
Nitrogen Dioxide ◽  
Human Life ◽  
Scattered Light ◽  
Fine Tuning ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Vertical Column ◽  
Airborne Measurements ◽  
The City

&lt;p&gt;Atmospheric pollution has a well-known impact on the human life, thus observing the emissions of trace gases is an important part of monitoring the atmospheric composition. This paper aims to determine the vertical column densities (VCDs) of Nitrogen Dioxide (NO&lt;sub&gt;2&lt;/sub&gt;) and Sulfur Dioxide (SO&lt;sub&gt;2&lt;/sub&gt;). These quantities will be used to calculate emissions of these pollutants quantified using a ground based mobile remote sensing technique that relies on scattered light DOAS (Differential Optical Absorption Spectroscopy) measurements. This method will be implemented using the SWING (Small Whiskbroom Imager for atmospheric compositioN monitorinG). The instrument is designed to perform airborne measurements, but for the purpose of this paper it was adapted for ground-based use by the National Institute for Aerospace Research (INCAS) in Bucharest, Romania. The source aimed to be quantified is the city of Bucharest, specifically the total emissions generated by the traffic and industry within the city. The measurements will be performed during the Spring of 2020 between February and April. The experimental setup consists of the SWING that will be mounted on the roof of a car, which allows to perform measurements along the ring road of Bucharest. There will be presented results from several days of measurements from a total of 150 hours of driving in terms of differential slant column densities (DSCDs), vertical column densities (VCDs) and quantified emissions of NO&amp;#173;&lt;sub&gt;2&lt;/sub&gt; and SO&lt;sub&gt;2&lt;/sub&gt;. This study will also be used for the fine tuning of the SWING operational parameters for use on UAV platforms in future measurement campaigns.&lt;/p&gt;

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