Articles | Volume 12, issue 8
Research article 06 Aug 2019
Research article | 06 Aug 2019
Evaluating and improving the reliability of gas-phase sensor system calibrations across new locations for ambient measurements and personal exposure monitoring
Sharad Vikram et al.
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Ashley M. Collier-Oxandale, Jacob Thorson, Hannah Halliday, Jana Milford, and Michael Hannigan
Atmos. Meas. Tech., 12, 1441–1460,Short summary
Airborne pollutants, such as volatile organic compounds, can present a danger to public and environmental health. We explored the potential for low-cost air quality sensors to help measure these compounds. From our deployment and the subsequent analysis, it seems these sensors can be calibrated to provide estimates of the levels of some individual and some groups of VOCs. This is promising as more cost-effective ways to measure VOCs could inform actions to reduce exposure.
Ashley Collier-Oxandale, Joanna Gordon Casey, Ricardo Piedrahita, John Ortega, Hannah Halliday, Jill Johnston, and Michael P. Hannigan
Atmos. Meas. Tech., 11, 3569–3594,Short summary
Low-cost air quality sensors and air quality sensor systems have the potential to open up new ways of measuring pollutants. In this paper, we explored ways to use low-cost sensors (approximately USD 10 per sensor) to estimate methane – a pollutant important for its contributions to climate change. We found that while these sensors will likely never replace traditional air quality monitoring methods, they can provide useful supplementary information on local pollution sources and regional trends.
Related subject area
Subject: Gases | Technique: In Situ Measurement | Topic: Data Processing and Information RetrievalEmissions relationships in western forest fire plumes – Part 1: Reducing the effect of mixing errors on emission factorsA new method to correct the electrochemical concentration cell (ECC) ozonesonde time response and its implications for “background current” and pump efficiencyMonitoring the compliance of sailing ships with fuel sulfur content regulations using unmanned aerial vehicle (UAV) measurements of ship emissions in open waterHigh-resolution mapping of urban air quality with heterogeneous observations: a new methodology and its application to AmsterdamTowards standardized processing of eddy covariance flux measurements of carbonyl sulfideIntegration and calibration of non-dispersive infrared (NDIR) CO2 low-cost sensors and their operation in a sensor network covering SwitzerlandCorrecting the impact of the isotope composition on the mixing ratio dependency of water vapour isotope measurements with cavity ring-down spectrometersCorrecting high-frequency losses of reactive nitrogen flux measurementsSurface flux estimates derived from UAS-based mole fraction measurements by means of a nocturnal boundary layer budget approachInnFLUX – an open-source code for conventional and disjunct eddy covariance analysis of trace gas measurements: an urban test caseAccurate measurements of atmospheric carbon dioxide and methane mole fractions at the Siberian coastal site AmbarchikTraffic-related air pollution near roadways: discerning local impacts from backgroundBayesian atmospheric tomography for detection and quantification of methane emissions: application to data from the 2015 Ginninderra release experimentA novel approach for simple statistical analysis of high-resolution mass spectraApplication of open-path Fourier transform infrared spectroscopy (OP-FTIR) to measure greenhouse gas concentrations from agricultural fieldsFlexible approach for quantifying average long-term changes and seasonal cycles of tropospheric trace speciesThe ICAD (iterative cavity-enhanced DOAS) methodDevelopment of an incoherent broadband cavity-enhanced absorption spectrometer for measurements of ambient glyoxal and NO2 in a polluted urban environmentAtmospheric CO2, CH4, and CO with the CRDS technique at the Izaña Global GAW station: instrumental tests, developments, and first measurement resultsPossible errors in flux measurements due to limited digitalizationDevelopment of a general calibration model and long-term performance evaluation of low-cost sensors for air pollutant gas monitoringAnalysis of spatial and temporal patterns of on-road NO2 concentrations in Hong KongTesting the performance of field calibration techniques for low-cost gas sensors in new deployment locations: across a county line and across ColoradoCalibration of isotopologue-specific optical trace gas analysers: a practical guideUncertainty of eddy covariance flux measurements over an urban area based on two towersExamination on total ozone column retrievals by Brewer spectrophotometry using different processing softwareUncertainty analysis of total ozone derived from direct solar irradiance spectra in the presence of unknown spectral deviationsIdentification of spikes associated with local sources in continuous time series of atmospheric CO, CO2 and CH4Bootstrap inversion technique for atmospheric trace gas source detection and quantification using long open-path laser measurementsAdaptive selection of diurnal minimum variation: a statistical strategy to obtain representative atmospheric CO2 data and its application to European elevated mountain stationsA machine learning calibration model using random forests to improve sensor performance for lower-cost air quality monitoringImproved methods for signal processing in measurements of mercury by Tekran® 2537A and 2537B instrumentsCH4 emission estimates from an active landfill site inferred from a combined approach of CFD modelling and in situ FTIR measurementsEddy covariance carbonyl sulfide flux measurements with a quantum cascade laser absorption spectrometerApplication of Gauss's theorem to quantify localized surface emissions from airborne measurements of wind and trace gasesA simple calculation algorithm to separate high-resolution CH4 flux measurements into ebullition- and diffusion-derived componentsImpact of biomass burning emission on total peroxy nitrates: fire plume identification during the BORTAS campaignContinuous and high-precision atmospheric concentration measurements of COS, CO2, CO and H2O using a quantum cascade laser spectrometer (QCLS)Random uncertainties of flux measurements by the eddy covariance techniqueQuantifying the uncertainty of eddy covariance fluxes due to the use of different software packages and combinations of processing steps in two contrasting ecosystemsA semiempirical error estimation technique for PWV derived from atmospheric radiosonde dataAutomatic processing of atmospheric CO2 and CH4 mole fractions at the ICOS Atmosphere Thematic CentreOptimal use of buffer volumes for the measurement of atmospheric gas concentration in multi-point systemsIncreasing the accuracy and temporal resolution of two-filter radon–222 measurements by correcting for the instrument responseIndustrial SO2 emission monitoring through a portable multichannel gas analyzer with an optimized retrieval algorithmMobile sensor network noise reduction and recalibration using a Bayesian networkComparison of the regional CO2 mole fraction filtering approaches at a WMO/GAW regional station in ChinaThe stability and calibration of water vapor isotope ratio measurements during long-term deploymentsEddy-covariance data with low signal-to-noise ratio: time-lag determination, uncertainties and limit of detectionPTRwid: A new widget tool for processing PTR-TOF-MS data
Robert B. Chatfield, Meinrat O. Andreae, ARCTAS Science Team, and SEAC4RS Science Team
Atmos. Meas. Tech., 13, 7069–7096,Short summary
Forest burning affects air pollution and global climate. A NASA aircraft studied fire emissions including the Rim Fire near Yosemite. We found frequent confusions between the actual fire emission factors and other effects on the air samples. Effects on CO2 and CO can originate far upwind; the gases can mix variably into a smoke plume. We devised a theory of constant features in plumes. A statistical mixed-effects analysis of a co-emitted tracers model disentangles such mixing from fire effects.
Holger Vömel, Herman G. J. Smit, David Tarasick, Bryan Johnson, Samuel J. Oltmans, Henry Selkirk, Anne M. Thompson, Ryan M. Stauffer, Jacquelyn C. Witte, Jonathan Davies, Roeland van Malderen, Gary A. Morris, Tatsumi Nakano, and Rene Stübi
Atmos. Meas. Tech., 13, 5667–5680,Short summary
The time response of electrochemical concentration cell (ECC) ozonesondes points to at least two distinct reaction pathways with time constants of approximately 20 s and 25 min. Properly considering these time constants eliminates the need for a poorly defined "background" and allows reducing ad hoc corrections based on laboratory tests. This reduces the uncertainty of ECC ozonesonde measurements throughout the profile and especially in regions of low ozone and strong gradients of ozone.
Fan Zhou, Liwei Hou, Rui Zhong, Wei Chen, Xunpeng Ni, Shengda Pan, Ming Zhao, and Bowen An
Atmos. Meas. Tech., 13, 4899–4909,Short summary
On 15 July 2019, using an unmanned aerial vehicle (UAV), maritime authorities ferreted out a sailing ship whose fuel sulfur content (FSC) failed to meet Chinese regulations. This was the first time that a sailing ship had been caught for having failed the FSC regulations in China. The UAV system, method, and monitoring result utilized are discussed in this paper. We recommend that emissions from sailing ships be monitored more often in the open water in the future.
Atmos. Meas. Tech., 13, 4601–4617,Short summary
Many cities are experimenting with networks of low-cost sensors, complementary to their reference stations. Often the observations are published as dots on a map, as spatial interpolation is far from trivial. A new methodology to assimilate observations of different accuracy in a generic urban-air-quality model is introduced. It can be used for mapping local air quality based on reference measurements only or as a framework to integrate low-cost measurements next to official measurements.
Kukka-Maaria Kohonen, Pasi Kolari, Linda M. J. Kooijmans, Huilin Chen, Ulli Seibt, Wu Sun, and Ivan Mammarella
Atmos. Meas. Tech., 13, 3957–3975,Short summary
Biosphere–atmosphere gas exchange (flux) measurements of carbonyl sulfide (COS) are becoming popular for estimating biospheric photosynthesis. To compare COS flux measurements across different measurement sites, we need standardized protocols for data processing. We analyze how various data processing steps affect the calculated COS flux and how they differ from carbon dioxide (CO2) flux processing steps, and we aim to settle on a set of recommended protocols for COS flux calculation.
Michael Müller, Peter Graf, Jonas Meyer, Anastasia Pentina, Dominik Brunner, Fernando Perez-Cruz, Christoph Hüglin, and Lukas Emmenegger
Atmos. Meas. Tech., 13, 3815–3834,
Yongbiao Weng, Alexandra Touzeau, and Harald Sodemann
Atmos. Meas. Tech., 13, 3167–3190,Short summary
We find that the known mixing ratio dependence of laser spectrometers for water vapour isotope measurements varies with isotope composition. We have developed a scheme to correct for this isotope-composition-dependent bias. The correction is most substantial at low mixing ratios. Stability tests indicate that the first-order dependency is a constant instrument characteristic. Water vapour isotope measurements at low mixing ratios can now be corrected by following our proposed procedure.
Pascal Wintjen, Christof Ammann, Frederik Schrader, and Christian Brümmer
Atmos. Meas. Tech., 13, 2923–2948,Short summary
With recent technological advances it is now possible to measure the exchange of trace gases between the land surface and the atmosphere. When using the so-called eddy-covariance method, certain corrections need to be applied to account for attenuation in the flux signal. These losses were found to be setup- and site-specific and can be up to 38 % for reactive nitrogen fluxes. We evaluated five different methods and recommend using an empirical version with locally measured cospectra.
Martin Kunz, Jost V. Lavric, Rainer Gasche, Christoph Gerbig, Richard H. Grant, Frank-Thomas Koch, Marcus Schumacher, Benjamin Wolf, and Matthias Zeeman
Atmos. Meas. Tech., 13, 1671–1692,Short summary
The nocturnal boundary layer (NBL) budget method enables the quantification of gas fluxes between ecosystems and the atmosphere under nocturnal stable stratification, a condition under which standard approaches struggle. However, up to now the application of the NBL method has been limited by difficulties in obtaining the required measurements. We show how an unmanned aircraft system (UAS) equipped with a carbon dioxide analyser can make this method more accessible.
Marcus Striednig, Martin Graus, Tilmann D. Märk, and Thomas G. Karl
Atmos. Meas. Tech., 13, 1447–1465,Short summary
The current work summarizes a long-term effort to provide an open-source code for the analysis of turbulent fluctuations of trace gases in the atmosphere by eddy covariance and disjunct eddy covariance, with a special focus on reactive gases that participate in atmospheric chemistry. The performance of the code is successfully evaluated based on measurements of minute fluxes of non-methane volatile organic compounds into the urban atmosphere.
Friedemann Reum, Mathias Göckede, Jost V. Lavric, Olaf Kolle, Sergey Zimov, Nikita Zimov, Martijn Pallandt, and Martin Heimann
Atmos. Meas. Tech., 12, 5717–5740,Short summary
We present continuous in situ measurements of atmospheric CO2 and CH4 mole fractions at the new station Ambarchik, located in northeastern Siberia. We describe the site, measurements and quality control, characterize the signals in comparison with data from Barrow, Alaska, and show which regions the measurements are sensitive to. Ambarchik data are available upon request.
Nathan Hilker, Jonathan M. Wang, Cheol-Heon Jeong, Robert M. Healy, Uwayemi Sofowote, Jerzy Debosz, Yushan Su, Michael Noble, Anthony Munoz, Geoff Doerksen, Luc White, Céline Audette, Dennis Herod, Jeffrey R. Brook, and Greg J. Evans
Atmos. Meas. Tech., 12, 5247–5261,Short summary
Increased interest in monitoring air quality near roadways, combined with traffic's often unclear contribution to elevated concentrations, has created a need for better interpretation of these data. Using 2 years of measurements collected during a near-road monitoring project in Canada, this paper contrasts three methods for estimating the fraction of roadside pollution resulting from on-road traffic. Robustness of these methods was compared with tandem measurements at background locations.
Laura Cartwright, Andrew Zammit-Mangion, Sangeeta Bhatia, Ivan Schroder, Frances Phillips, Trevor Coates, Karita Negandhi, Travis Naylor, Martin Kennedy, Steve Zegelin, Nick Wokker, Nicholas M. Deutscher, and Andrew Feitz
Atmos. Meas. Tech., 12, 4659–4676,Short summary
Despite extensive research, emission detection and quantification of greenhouse gases (GHGs) remain an open problem. This article presents a novel statistical framework for detecting and quantifying methane emissions and showcases its efficacy on data collected from different instruments in the 2015 Ginninderra controlled-release experiment. The developed techniques can be used to aid GHG emission reduction schemes by, for example, detecting and quantifying leaks from carbon storage facilities.
Yanjun Zhang, Otso Peräkylä, Chao Yan, Liine Heikkinen, Mikko Äijälä, Kaspar R. Daellenbach, Qiaozhi Zha, Matthieu Riva, Olga Garmash, Heikki Junninen, Pentti Paatero, Douglas Worsnop, and Mikael Ehn
Atmos. Meas. Tech., 12, 3761–3776,Short summary
Recent advancements in atmospheric mass spectrometry provide large amounts of new information but at the same time present considerable challenges for the data analysis, for example, in high-resolution peak identification and separation. To address these problems, this study presents a simple and novel method, which succeeds in analyzing both synthetic and ambient datasets. We believe it will become a powerful approach in the data analysis of mass spectra.
Cheng-Hsien Lin, Richard H. Grant, Albert J. Heber, and Cliff T. Johnston
Atmos. Meas. Tech., 12, 3403–3415,Short summary
The open-path FTIR (OP-FTIR) is often used to measure the atmospheric gas composition and concentrations. The OP-FTIR, however, is sensitive to the changed ambient factors, which likely led to quantitative biases. This study developed methods to minimize the effect of the ambient temperature and humidity on N2O/CO2 quantification. These methods can help the users who implement the OP-FTIR to estimate gas fluxes in the agroecosystem achieve more precise and accurate estimations.
David D. Parrish, Richard G. Derwent, Simon O'Doherty, and Peter G. Simmonds
Atmos. Meas. Tech., 12, 3383–3394,Short summary
We present a flexible method that employs a power series expansion and Fourier series analysis to characterize the average long-term change and seasonal cycle, respectively, from a time series of observations of a trace atmospheric species. This approach maximizes the statistically significant information derived, including non-linear aspects of the long-term trends, without over fitting the data. Generally, a small set of parameter values (e.g., 7 or 8) provides this characterization.
Martin Horbanski, Denis Pöhler, Johannes Lampel, and Ulrich Platt
Atmos. Meas. Tech., 12, 3365–3381,Short summary
ICAD allows a precise in situ measurement of gases like NO2 in a relatively simple and compact setup. The main advantage in comparison to most other optical methods is that it does not require a stable total light intensity. This allows a simpler and mobile instrument setup and additionally it features no observed cross-interferences. We validated the high quality for an ICAD NO2 instrument in different inter-comparisons with a detection limit of 0.02 ppbv.
Shuaixi Liang, Min Qin, Pinhua Xie, Jun Duan, Wu Fang, Yabai He, Jin Xu, Jingwei Liu, Xin Li, Ke Tang, Fanhao Meng, Kaidi Ye, Jianguo Liu, and Wenqing Liu
Atmos. Meas. Tech., 12, 2499–2512,Short summary
A home-built instrument of an incoherent broadband cavity-enhanced absorption spectrometer is reported for sensitive detection of CHOCHO and NO2 in China's highly polluted environment. An NO2 spectral profile measured using the same spectrometer is applied as a reference spectral profile in the subsequent atmospheric spectral analysis and retrieval of NO2 and CHOCHO. This will provide an idea for solving the problem of cross-interference of strongly absorbing gases in weakly absorbing gases.
Angel J. Gomez-Pelaez, Ramon Ramos, Emilio Cuevas, Vanessa Gomez-Trueba, and Enrique Reyes
Atmos. Meas. Tech., 12, 2043–2066,Short summary
In 2015, a CO2/CH4/CO CRDS was installed at Izaña station (Tenerife). We present the acceptance tests, the processing of raw data applied, the ambient measurements performed, and their comparison with other continuous in situ measurements. We determine linear relationships between flow rate, CRDS inlet pressure, and CRDS outlet valve aperture; a slight CO2 correction that takes into account changes in the inlet pressure/flow rate and its origin; and the H2O correction for CO in a novel way.
Thomas Foken, Wolfgang Babel, and Christoph Thomas
Atmos. Meas. Tech., 12, 971–976,Short summary
Recently reported trends of carbon dioxide uptake pose the question of whether trends may be the result of the limited digitalization of gas analysers and sonic anemometers used in the 1990s. Modifying a 12 bit digitalization and the instrument error reported for the R2 and R3 sonic anemometers found elsewhere, the influence of these deficits in comparison to the now commonly used 16 bit digitalization were quantified. Both issues have an effect only on trace gas fluxes of small magnitude.
Carl Malings, Rebecca Tanzer, Aliaksei Hauryliuk, Sriniwasa P. N. Kumar, Naomi Zimmerman, Levent B. Kara, Albert A. Presto, and R. Subramanian
Atmos. Meas. Tech., 12, 903–920,Short summary
This paper compares several methods for calibrating data from low-cost air quality monitors to reflect the concentrations of various gaseous pollutants in the atmosphere, identifying the best-performing approaches. With these calibration methods, such monitors can be used to gather information on air quality at a higher spatial resolution than is possible using traditional technologies and can be deployed to areas (e.g. developing countries) where there are no existing monitor networks.
Ying Zhu, Ka Lok Chan, Yun Fat Lam, Martin Horbanski, Denis Pöhler, Johannes Boll, Ivo Lipkowitsch, Sheng Ye, and Mark Wenig
Atmos. Meas. Tech., 11, 6719–6734,Short summary
The paper presents an investigation of spatio-temporal variability of street-level NO2 in Hong Kong using mobile cavity-enhanced differential optical absorption spectroscopy (DOAS) and long-path DOAS. Measurements were conducted in December 2010 and March 2017. A significant decreasing trend in on-road NO2 was found by comparing measurements taken in 2010 and 2017. Influences of changes in bus companies' operation strategies can also be observed from the measured NO2 concentration maps.
Joanna Gordon Casey and Michael P. Hannigan
Atmos. Meas. Tech., 11, 6351–6378,Short summary
Low-cost sensors have the potential to improve understanding of air quality in complex regions like oil and gas production basins. Regression methods have been used to quantify pollutants from sensor signals, but these methods have not been tested when sensors are moved to new sampling locations, away from model training locations. We use sensor data collected at multiple sites to test how well these field calibration methods perform when they are extended to new locations and times.
David W. T. Griffith
Atmos. Meas. Tech., 11, 6189–6201,Short summary
In recent years optical spectroscopic techniques have become commonly used in the determination of mole fractions of trace gases in air. These techniques in many cases determine the mole fractions of only individual isotopic variants (
isotopologues) of the trace gas, while for many applications the total mole fraction of all isotopologues is required. This paper sets out the measurements and calculations required to convert between individual isotopologue and total trace gas amounts.
Leena Järvi, Üllar Rannik, Tom V. Kokkonen, Mona Kurppa, Ari Karppinen, Rostislav D. Kouznetsov, Pekka Rantala, Timo Vesala, and Curtis R. Wood
Atmos. Meas. Tech., 11, 5421–5438,Short summary
Identical EC systems on two sides of a building in central Helsinki were used to assess the uncertainty of the vertical fluxes on the single measurement point from July 2013 to September 2015. Sampling at only one point yielded up to 12% underestimation in the cumulative carbon fluxes; for sensible and latent heat the respective values were up to 5 and 8%. The commonly used statistics, kurtosis and skewness, are not necessarily suitable for filtering out data in a densely built urban area.
Anna Maria Siani, Francesca Frasca, Francesco Scarlatti, Arianna Religi, Henri Diémoz, Giuseppe R. Casale, Massimiliano Pedone, and Volodya Savastiouk
Atmos. Meas. Tech., 11, 5105–5123,Short summary
Total ozone columns (TOCs) measured by Brewer spectrophotometers located at Rome and Aosta (Italy) were calculated using different processing software packages, and the differences in the TOC retrievals are investigated. Large differences in TOC retrievals can be experienced when the instrumental sensitivity exhibits a long-term drift. The variability in TOC retrievals depends on the algorithm for calculating the standard lamp correction.
Anna Vaskuri, Petri Kärhä, Luca Egli, Julian Gröbner, and Erkki Ikonen
Atmos. Meas. Tech., 11, 3595–3610,Short summary
In this work, we introduce a Monte Carlo uncertainty analysis that takes into account possible systematic spectral deviations in the atmospheric full spectrum ozone retrieval method. Accounting for possible systematic spectral deviations in the spectral data is important since they produce larger total ozone column uncertainties than uncorrelated noise-like variations that traditional uncertainty estimations predict.
Abdelhadi El Yazidi, Michel Ramonet, Philippe Ciais, Gregoire Broquet, Isabelle Pison, Amara Abbaris, Dominik Brunner, Sebastien Conil, Marc Delmotte, Francois Gheusi, Frederic Guerin, Lynn Hazan, Nesrine Kachroudi, Giorgos Kouvarakis, Nikolaos Mihalopoulos, Leonard Rivier, and Dominique Serça
Atmos. Meas. Tech., 11, 1599–1614,
Caroline B. Alden, Subhomoy Ghosh, Sean Coburn, Colm Sweeney, Anna Karion, Robert Wright, Ian Coddington, Gregory B. Rieker, and Kuldeep Prasad
Atmos. Meas. Tech., 11, 1565–1582,Short summary
The location and sizing leaks of methane from natural gas operations poses a real challenge for greenhouse gas emission mitigation efforts and for accurate quantification of emissions inventories. We demonstrate, with synthetic and field tests, a new statistical method for the location and sizing of small trace gas point sources dispersed over large areas, based on measurements of ambient atmospheric conditions made with long-range, open-path laser-based atmospheric observations.
Ye Yuan, Ludwig Ries, Hannes Petermeier, Martin Steinbacher, Angel J. Gómez-Peláez, Markus C. Leuenberger, Marcus Schumacher, Thomas Trickl, Cedric Couret, Frank Meinhardt, and Annette Menzel
Atmos. Meas. Tech., 11, 1501–1514,Short summary
This paper presents a novel statistical method, ADVS, for baseline selection of representative CO2 data at elevated mountain measurement stations. It provides insights on how data processing techniques are critical for measurements and data analyses. Compared with other statistical methods, our method appears to be a good option as a generalized approach with improved comparability, which is important for research on measurement site characteristics and comparisons between stations.
Naomi Zimmerman, Albert A. Presto, Sriniwasa P. N. Kumar, Jason Gu, Aliaksei Hauryliuk, Ellis S. Robinson, Allen L. Robinson, and R. Subramanian
Atmos. Meas. Tech., 11, 291–313,Short summary
Low-cost sensors promise neighborhood-scale air quality monitoring but have been plagued by inconsistent performance for precision, accuracy, and drift. CMU and SenSevere collaborated to develop the RAMP, which uses electrochemical sensors. We present a machine learning algorithm that overcomes previous performance issues and meets US EPA's data quality recommendations for personal exposure for NO2 and tougher "supplemental monitoring" standards for CO & ozone across 19 RAMPs for several months.
Jesse L. Ambrose
Atmos. Meas. Tech., 10, 5063–5073,Short summary
Scientific understanding of environmental Hg cycling is limited by analytical uncertainties. To better characterize analytical uncertainty associated with Hg measurements made with the Tekran® 2537 instrument, I developed new software-based methods for offline processing of the raw instrumental data. I demonstrate significant uncertainty associated with the Tekran® method. By comparison, my methods improve measurement accuracy and the Hg detection limit by as much as 95 % and 88 %, respectively.
Hannah Sonderfeld, Hartmut Bösch, Antoine P. R. Jeanjean, Stuart N. Riddick, Grant Allen, Sébastien Ars, Stewart Davies, Neil Harris, Neil Humpage, Roland Leigh, and Joseph Pitt
Atmos. Meas. Tech., 10, 3931–3946,Short summary
The waste sector is the second largest source of methane in the UK. However, uncertainties of methane emissions from landfill sites still remain. In this study we present a new approach for the estimation of methane emissions from a landfill site by applying a computational fluid dynamics (CFD) model for precise measurements of methane with in situ Fourier-transform infrared (FTIR) spectroscopy. Different source areas could be distinguished with this method and their emissions were assessed.
Katharina Gerdel, Felix Maximilian Spielmann, Albin Hammerle, and Georg Wohlfahrt
Atmos. Meas. Tech., 10, 3525–3537,
Stephen Conley, Ian Faloona, Shobhit Mehrotra, Maxime Suard, Donald H. Lenschow, Colm Sweeney, Scott Herndon, Stefan Schwietzke, Gabrielle Pétron, Justin Pifer, Eric A. Kort, and Russell Schnell
Atmos. Meas. Tech., 10, 3345–3358,Short summary
This paper describes a new method of quantifying surface trace gas emissions (e.g. methane) from small aircraft (e.g. Mooney, Cessna) in about 30 min. This technique greatly enhances our ability to rapidly respond in the event of catastrophic failures such as Aliso Canyon and Deep Water Horizon.
Mathias Hoffmann, Maximilian Schulz-Hanke, Juana Garcia Alba, Nicole Jurisch, Ulrike Hagemann, Torsten Sachs, Michael Sommer, and Jürgen Augustin
Atmos. Meas. Tech., 10, 109–118,Short summary
Processes driving production and transport of CH4 in wetlands are complex. We present an algorithm to separate open-water automatic chamber CH4 fluxes into diffusion and ebullition. This helps to reveal dynamics, identify drivers and obtain reliable CH4 emissions. The algorithm is based on sudden concentration changes during single measurements. A variable filter is applied using a multiple of the interquartile range. The algorithm was verified for data of a rewetted former fen grassland site.
Eleonora Aruffo, Fabio Biancofiore, Piero Di Carlo, Marcella Busilacchio, Marco Verdecchia, Barbara Tomassetti, Cesare Dari-Salisburgo, Franco Giammaria, Stephane Bauguitte, James Lee, Sarah Moller, James Hopkins, Shalini Punjabi, Stephen J. Andrews, Alistair C. Lewis, Paul I. Palmer, Edward Hyer, Michael Le Breton, and Carl Percival
Atmos. Meas. Tech., 9, 5591–5606,Short summary
During the BORTAS aircraft campaign, we measured NO2 and their oxidtation products (as peroxy nitrates) with a custom laser-induced fluorescence instrument. Because of the high correlation between known pyrogenic tracers (i.e., carbon monoxide) and peroxy nitrates, we provide two methods to use these species for the identification of biomass burning (BB) plumes. Using an artifical neural network, we improved the BB identification taking into account of a meteorological parameter (pressure).
Linda M. J. Kooijmans, Nelly A. M. Uitslag, Mark S. Zahniser, David D. Nelson, Stephen A. Montzka, and Huilin Chen
Atmos. Meas. Tech., 9, 5293–5314,Short summary
The accuracy of carbon models, used for the prediction of global climate change, is limited by the knowledge of the uptake of carbon by plants through photosynthesis. Carbonyl sulfide (COS) has been suggested as a tracer for this process. To be able to further explore and verify the application of this novel tracer we have tested a laser spectrometer for its suitability to obtain accurate and high precision measurements of COS and CO2 with both laboratory experiments and field measurements.
Üllar Rannik, Olli Peltola, and Ivan Mammarella
Atmos. Meas. Tech., 9, 5163–5181,Short summary
We review available methods for the random error estimation of turbulent fluxes that are widely used by the flux community. Flux errors are evaluated theoretically as well as via numerical calculations by using measured and simulated records. We recommend two flux random errors with clear physical meaning: the total error resulting from stochastic nature of turbulence, well approximated by the method of Finkelstein and Sims (2001), and the error of the flux due to the instrumental noise.
Ivan Mammarella, Olli Peltola, Annika Nordbo, Leena Järvi, and Üllar Rannik
Atmos. Meas. Tech., 9, 4915–4933,Short summary
In this study we have performed an inter-comparison between EddyUH and EddyPro, two public and commonly used software packages for eddy covariance data processing and calculation. The aims are to estimate the flux uncertainty due to the use of different software packages, and to assess the most critical processing steps, determining the largest deviations in the calculated fluxes. We focus not only on water vapour and carbon dioxide fluxes, but also on the methane flux.
Julio A. Castro-Almazán, Gabriel Pérez-Jordán, and Casiana Muñoz-Tuñón
Atmos. Meas. Tech., 9, 4759–4781,Short summary
Water vapour is the main responsible for the atmospheric extinction in astronomical observations in different bands. One of the most common and accurate techniques to measure it are the radiosoundings. A method to estimate the error and the optimum number of sampled levels is proposed, considering the uncertainties and the leakage in sampling, based on data from Roque de los Muchachos Observ. and Guimar (Canary Is., Spain), Lindenberg (Germany) and Ny-Ålesund (Norway). The median error is 2.0 %.
Lynn Hazan, Jérôme Tarniewicz, Michel Ramonet, Olivier Laurent, and Amara Abbaris
Atmos. Meas. Tech., 9, 4719–4736,Short summary
The ATC automatically processes atmospheric greenhouse gases mole fractions of data sent daily by the ICOS network, this includes calibration and water vapor corrections. Data are stored in a database which has been developed with an emphasis on traceability. Instrument calibration and manual quality control lead to automatic revaluation of the mole fractions calculated in near-real time. Calibration corrections avoid artificial gradients between sites that could lead to error in flux estimates.
Alessandro Cescatti, Barbara Marcolla, Ignacio Goded, and Carsten Gruening
Atmos. Meas. Tech., 9, 4665–4672,Short summary
Multi-point monitoring systems are required to measure atmospheric gas concentrations at tall towers and eddy covariance sites. The use of buffer volumes can reduce the uncertainty due to the discrete temporal sampling. We propose a processing scheme that accounts for the fraction of signal built up in the averaging period and reduces the error up to 80 % compared to the standard setup. A relationship is derived to estimate the optimal volume size given the specifications of the sampling system.
Alan D. Griffiths, Scott D. Chambers, Alastair G. Williams, and Sylvester Werczynski
Atmos. Meas. Tech., 9, 2689–2707,Short summary
Surface-based two-filter radon detectors monitor the ambient concentration of atmospheric radon-222, a natural tracer of mixing and transport. They are sensitive, but respond slowly to ambient changes in radon concentration. In this paper, a deconvolution method is used to successfully correct observations for the instrument response. Case studies demonstrate that it is beneficial, sometimes necessary, to account for the detector response, especially when studying near-surface mixing.
Youwen Sun, Cheng Liu, Pinhua Xie, Andreas Hartl, Kalok Chan, Yuan Tian, Wei Wang, Min Qin, Jianguo Liu, and Wenqing Liu
Atmos. Meas. Tech., 9, 1167–1180,Short summary
SO2 variability over a large concentration range and interferences from other gases have been major limitations in industrial SO2 emission monitoring. This study demonstrates accurate industrial SO2 emission monitoring through a portable multichannel gas analyzer with an optimized retrieval algorithm. The developed instrument shows good performance in both the linear and nonlinear ranges.
Y. Xiang, Y. Tang, and W. Zhu
Atmos. Meas. Tech., 9, 347–357,Short summary
Motivated by unreliable sensor readings and the difficulties in calibrating sensors, we developed a Bayesian-network-based method to remove the abnormal readings and re-calibrate the sensors.
S. X. Fang, P. P. Tans, M. Steinbacher, L. X. Zhou, and T. Luan
Atmos. Meas. Tech., 8, 5301–5313,Short summary
The identification of atmospheric CO2 observation data which are minimally influenced by very local emissions/removals is essential for trend analysis and for the estimation of regional sources and sinks. We compared four data filtering regimes based on the observation records at Lin'an station in China, and found that the use of meteorological parameters was the most favorable. This conclusion will aid regional data selection at the Lin'an station.
A. Bailey, D. Noone, M. Berkelhammer, H. C. Steen-Larsen, and P. Sato
Atmos. Meas. Tech., 8, 4521–4538,Short summary
This study evaluates the long-term stability of concentration-dependent and drift-induced biases in three water vapor isotopic analyzers deployed at two remote field sites. Despite limited data at low humidity and measurement hysteresis, inaccuracies in the concentration-dependence characterization are small, and the bias shows no change with isotope ratio or directional drift. Changes in measurement repeatability that are not characterized by linear drift estimates are a larger source of error.
B. Langford, W. Acton, C. Ammann, A. Valach, and E. Nemitz
Atmos. Meas. Tech., 8, 4197–4213,
Atmos. Meas. Tech., 8, 3903–3922,
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Low-cost air quality sensors are enabling people to collect data to better understand their local environment and potential exposures. However, there is some concern regarding how reliable the calibrations of these sensors are in new and different environments. To explore this issue, our team colocated sensors at three different sites with high-quality monitoring instruments to compare to. We explored the transferability of calibration models as well as approaches to improve reliability.
Low-cost air quality sensors are enabling people to collect data to better understand their...