Articles | Volume 14, issue 8
Research article 26 Aug 2021
Research article | 26 Aug 2021
SIBaR: a new method for background quantification and removal from mobile air pollution measurements
Blake Actkinson et al.
No articles found.
Dandan Wei, Hariprasad D. Alwe, Dylan B. Millet, Brandon Bottorff, Michelle Lew, Philip S. Stevens, Joshua D. Shutter, Joshua L. Cox, Frank N. Keutsch, Qianwen Shi, Sarah C. Kavassalis, Jennifer G. Murphy, Krystal T. Vasquez, Hannah M. Allen, Eric Praske, John D. Crounse, Paul O. Wennberg, Paul B. Shepson, Alexander A. T. Bui, Henry W. Wallace, Robert J. Griffin, Nathaniel W. May, Megan Connor, Jonathan H. Slade, Kerri A. Pratt, Ezra C. Wood, Mathew Rollings, Benjamin L. Deming, Daniel C. Anderson, and Allison L. Steiner
Geosci. Model Dev., 14, 6309–6329,Short summary
Over the past decade, understanding of isoprene oxidation has improved, and proper representation of isoprene oxidation and isoprene-derived SOA (iSOA) formation in canopy–chemistry models is now recognized to be important for an accurate understanding of forest–atmosphere exchange. The updated FORCAsT version 2.0 improves the estimation of some isoprene oxidation products and is one of the few canopy models currently capable of simulating SOA formation from monoterpenes and isoprene.
Alexander A. T. Bui, Henry W. Wallace, Sarah Kavassalis, Hariprasad D. Alwe, James H. Flynn, Matt H. Erickson, Sergio Alvarez, Dylan B. Millet, Allison L. Steiner, and Robert J. Griffin
Atmos. Chem. Phys. Discuss.,
Revised manuscript accepted for ACPShort summary
Differences in atmospheric species above and below a forest canopy provide insight into the relative importance of local mixing, long-range transport, and chemical processes on determining vertical gradients in atmospheric particles in a forested environment. This helps to understand the flux of climate-relevant material out of the forest to the atmosphere. We studied this in a remote forest using vertically resolved measurements of gases and particles.
Candice L. Sirmollo, Don R. Collins, Jordan M. McCormick, Cassandra F. Milan, Matthew H. Erickson, James H. Flynn, Rebecca J. Sheesley, Sascha Usenko, Henry W. Wallace, Alexander A. T. Bui, Robert J. Griffin, Matthew Tezak, Sean M. Kinahan, and Joshua L. Santarpia
Atmos. Meas. Tech., 14, 3351–3370,Short summary
The newly developed portable 1 m3 CAGE chamber systems were characterized using data acquired during a 2-month field study in 2016 in a forested area north of Houston, TX, USA. Concentrations of several oxidant and organic compounds measured in the chamber were found to closely agree with those calculated with a zero-dimensional model. By tracking the modes of injected monodisperse particles, a pattern change was observed for hourly averaged growth rates between late summer and early fall.
Loredana G. Suciu, Robert J. Griffin, and Caroline A. Masiello
Geosci. Model Dev., 14, 907–921,Short summary
Understanding the atmospheric degradation of biomass burning tracers such as levoglucosan is essential to decreasing uncertainties in the role of biomass burning in air quality, carbon cycling and paleoclimate. Using a 0-D modeling approach and numerical chamber simulations, we found that the multiphase atmospheric degradation of levoglucosan occurs over timescales of hours to days, can form secondary organic aerosols and affects other key tropospheric gases, such as ozone.
Qili Dai, Benjamin C. Schulze, Xiaohui Bi, Alexander A. T. Bui, Fangzhou Guo, Henry W. Wallace, Nancy P. Sanchez, James H. Flynn, Barry L. Lefer, Yinchang Feng, and Robert J. Griffin
Atmos. Chem. Phys., 19, 9641–9661,Short summary
The formation processes of secondary organic aerosol remain to be fully understood. We reported the measurement data from two field campaigns within Houston, TX, to investigate the effects of aqueous-phase chemistry and photochemistry in processing oxygenated organic aerosol (OOA) in winter and summer. Both photochemistry and aqueous-phase processing appear to facilitate more-oxidized OOA formation. The processing mechanism of less-oxidized OOA apparently depended on relative humidity.
Ibrahim M. Al-Naiema, Anusha P. S. Hettiyadura, Henry W. Wallace, Nancy P. Sanchez, Carter J. Madler, Basak Karakurt Cevik, Alexander A. T. Bui, Josh Kettler, Robert J. Griffin, and Elizabeth A. Stone
Atmos. Chem. Phys., 18, 15601–15622,Short summary
By integrating newly developed tracers for anthropogenic secondary organic aerosol in source apportionment for the first time, we estimate that this source contributes 28 % of fine particle organic carbon in the Houston Ship Channel. Our approach can be used to evaluate anthropogenic, biogenic, and biomass burning contributions to secondary organic aerosols elsewhere in the world. Because anthropogenic emissions are potentially controllable, they provide an opportunity to improve air quality.
Benjamin C. Schulze, Henry W. Wallace, Alexander T. Bui, James H. Flynn, Matt H. Erickson, Sergio Alvarez, Qili Dai, Sascha Usenko, Rebecca J. Sheesley, and Robert J. Griffin
Atmos. Chem. Phys., 18, 14217–14241,Short summary
Atmospheric field measurements at a coastal site near Houston, TX, were used to investigate the influence of shipping vessel emissions on aerosol mass and composition over the Gulf of Mexico. Results suggest that, despite recent regulations, these vessels still produce a considerable fraction of inorganic and organic aerosol mass in the region. Secondary effects of shipping emissions on organic aerosol composition, such as influences on aerosol aging, were also identified.
Loredana G. Suciu, Robert J. Griffin, and Caroline A. Masiello
Atmos. Chem. Phys., 17, 6565–6581,Short summary
Understanding of the variability of ozone (O3) in space and time is essential to the design of efficient air quality controls. We used statistical analysis of O3, nitrogen oxides (NOx) and weather measurements to estimate the large-scale contributions of O3 and NOx in southeastern Texas. We found that these “external” contributions have declined over time, likely due to a combination of controls on O3 precursors and increases in the frequency of prevailing southerly flow from the Gulf of Mexico.
Nga Lee Ng, Steven S. Brown, Alexander T. Archibald, Elliot Atlas, Ronald C. Cohen, John N. Crowley, Douglas A. Day, Neil M. Donahue, Juliane L. Fry, Hendrik Fuchs, Robert J. Griffin, Marcelo I. Guzman, Hartmut Herrmann, Alma Hodzic, Yoshiteru Iinuma, José L. Jimenez, Astrid Kiendler-Scharr, Ben H. Lee, Deborah J. Luecken, Jingqiu Mao, Robert McLaren, Anke Mutzel, Hans D. Osthoff, Bin Ouyang, Benedicte Picquet-Varrault, Ulrich Platt, Havala O. T. Pye, Yinon Rudich, Rebecca H. Schwantes, Manabu Shiraiwa, Jochen Stutz, Joel A. Thornton, Andreas Tilgner, Brent J. Williams, and Rahul A. Zaveri
Atmos. Chem. Phys., 17, 2103–2162,Short summary
Oxidation of biogenic volatile organic compounds by NO3 is an important interaction between anthropogenic and natural emissions. This review results from a June 2015 workshop and includes the recent literature on kinetics, mechanisms, organic aerosol yields, and heterogeneous chemistry; advances in analytical instrumentation; the current state NO3-BVOC chemistry in atmospheric models; and critical needs for future research in modeling, field observations, and laboratory studies.
Benjamin C. Schulze, Henry W. Wallace, James H. Flynn, Barry L. Lefer, Matt H. Erickson, B. Tom Jobson, Sebastien Dusanter, Stephen M. Griffith, Robert F. Hansen, Philip S. Stevens, Timothy VanReken, and Robert J. Griffin
Atmos. Chem. Phys., 17, 1805–1828,Short summary
The atmospheric chemistry associated with mixing of anthropogenic and natural species was simulated to understand how shade provided by a forest canopy impacts reactions, product distribution, and subsequent phase distribution of the products. This is important to understand, as forested areas downwind of urban areas will be impacted by this phenomenon. It was found that fast transport from below the canopy led to increases in secondary organic aerosol from nitrate radicals above the canopy.
Matthew L. Dawson, Jialu Xu, Robert J. Griffin, and Donald Dabdub
Geosci. Model Dev., 9, 2143–2151,Short summary
The atmospheric oxidation of aromatic compounds is an important source of aerosol-forming species, and thus contributes to pollution in urban areas. However, details of the mechanisms by which oxidation occurs are only recently being elucidated. Here we report the incorporation of a newly developed mechanism for aromatic oxidation into the UCI-CIT regional air quality model. Results suggest an unexpected role for chemical pathways typically associated with cleaner environments.
K. Ashworth, S. H. Chung, R. J. Griffin, J. Chen, R. Forkel, A. M. Bryan, and A. L. Steiner
Geosci. Model Dev., 8, 3765–3784,Short summary
Volatile organic compounds released from forests into the atmosphere play a key role in governing atmospheric concentrations of trace gases and aerosol particles. We describe the development of a 1-D model that simulates the processes occurring within and above the forest canopy that regulate the transfer of these compounds and their products. We evaluate model performance by comparison of modelled concentrations against measurements from a field campaign at a northern Michigan forest site.
Related subject area
Subject: Gases | Technique: In Situ Measurement | Topic: Data Processing and Information RetrievalAn algorithm to detect non-background signals in greenhouse gas time series from European tall tower and mountain stationsMobile atmospheric measurements and local-scale inverse estimation of the location and rates of brief CH4 and CO2 releases from point sourcesMachine learning calibration of low-cost NO2 and PM10 sensors: non-linear algorithms and their impact on site transferabilityThe high-frequency response correction of eddy covariance fluxes – Part 2: An experimental approach for analysing noisy measurements of small fluxesThe high-frequency response correction of eddy covariance fluxes – Part 1: An experimental approach and its interdependence with the time-lag estimationUncertainty of hourly-average concentration values derived from non-continuous measurementsUnraveling a black box: An open-source methodology for the field calibration of small air quality sensorsEmissions 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 experimentEvaluating and improving the reliability of gas-phase sensor system calibrations across new locations for ambient measurements and personal exposure monitoringA 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 Centre
Alex Resovsky, Michel Ramonet, Leonard Rivier, Jerome Tarniewicz, Philippe Ciais, Martin Steinbacher, Ivan Mammarella, Meelis Mölder, Michal Heliasz, Dagmar Kubistin, Matthias Lindauer, Jennifer Müller-Williams, Sebastien Conil, and Richard Engelen
Atmos. Meas. Tech., 14, 6119–6135,Short summary
We present a technical description of a statistical methodology for extracting synoptic- and seasonal-length anomalies from greenhouse gas time series. The definition of what represents an anomalous signal is somewhat subjective, which we touch on throughout the paper. We show, however, that the method performs reasonably well in extracting portions of time series influenced by significant North Atlantic Oscillation weather episodes and continent-wide terrestrial biospheric aberrations.
Pramod Kumar, Grégoire Broquet, Camille Yver-Kwok, Olivier Laurent, Susan Gichuki, Christopher Caldow, Ford Cropley, Thomas Lauvaux, Michel Ramonet, Guillaume Berthe, Frédéric Martin, Olivier Duclaux, Catherine Juery, Caroline Bouchet, and Philippe Ciais
Atmos. Meas. Tech., 14, 5987–6003,Short summary
This study presents a simple atmospheric inversion modeling framework for the localization and quantification of unknown CH4 and CO2 emissions from point sources based on near-surface mobile concentration measurements and a Gaussian plume dispersion model. It is applied for the estimate of a series of brief controlled releases of CH4 and CO2 with a wide range of rates during the TOTAL TADI-2018 experiment. Results indicate a ~10 %–40 % average error on the estimate of the release rates.
Peer Nowack, Lev Konstantinovskiy, Hannah Gardiner, and John Cant
Atmos. Meas. Tech., 14, 5637–5655,Short summary
Machine learning (ML) calibration techniques could be an effective way to improve the performance of low-cost air pollution sensors. Here we provide novel insights from case studies within the urban area of London, UK, where we compared the performance of three ML techniques to calibrate low-cost measurements of NO2 and PM10. In particular, we highlight the key issue of the method-dependent robustness in maintaining calibration skill after transferring sensors to different measurement sites.
Toprak Aslan, Olli Peltola, Andreas Ibrom, Eiko Nemitz, Üllar Rannik, and Ivan Mammarella
Atmos. Meas. Tech., 14, 5089–5106,Short summary
Vertical turbulent fluxes of gases measured by the eddy covariance (EC) technique are subject to high-frequency losses. There are different methods used to describe this low-pass filtering effect and to correct the measured fluxes. In this study, we analysed the systematic uncertainty related to this correction for various attenuation and signal-to-noise ratios. A new and robust transfer function method is finally proposed.
Olli Peltola, Toprak Aslan, Andreas Ibrom, Eiko Nemitz, Üllar Rannik, and Ivan Mammarella
Atmos. Meas. Tech., 14, 5071–5088,Short summary
Gas fluxes measured by the eddy covariance (EC) technique are subject to filtering due to non-ideal instrumentation. For linear first-order systems this filtering causes also a time lag between vertical wind speed and gas signal which is additional to the gas travel time in the sampling line. The effect of this additional time lag on EC fluxes is ignored in current EC data processing routines. Here we show that this oversight biases EC fluxes and hence propose an approach to rectify this bias.
László Haszpra and Ernő Prácser
Atmos. Meas. Tech., 14, 3561–3571,Short summary
Most of the tall-tower greenhouse gas observatories apply a single gas analyzer for the sequential sampling of several intakes along the tower. The non-continuous sampling at each intake introduces excess uncertainty to the calculated hourly-average concentrations used in several applications. Based on real-world measurements, the paper systematically assesses this type of uncertainty.
Seán Schmitz, Sherry Towers, Guillermo Villena, Alexandre Caseiro, Robert Wegener, Dieter Klemp, Ines Langer, Fred Meier, and Erika von Schneidemesser
Atmos. Meas. Tech. Discuss.,
Revised manuscript accepted for AMTShort summary
The last two decades have seen substantial technological advances in the development of low-cost air pollution instruments. This study introduces a 7-step methodology for the field calibration of low-cost sensors with user-friendly guidelines, open access code, and a discussion of common barriers. Our goal with this work is to push for standardized reporting of methods, to make critical data processing steps clear for users, and encourage responsible use in the scientific community and beyond.
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.
Sharad Vikram, Ashley Collier-Oxandale, Michael H. Ostertag, Massimiliano Menarini, Camron Chermak, Sanjoy Dasgupta, Tajana Rosing, Michael Hannigan, and William G. Griswold
Atmos. Meas. Tech., 12, 4211–4239,Short summary
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.
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.
Actkinson, B., Ensor, K., and Griffin, R. J.: Time Series Comparisons, Model Code, and a Demo Dataset for SIBaR: A New Method for Background Quantification and Removal from Mobile Air Pollution Measurements, Zenodo [data set], https://doi.org/10.5281/zenodo.5022590, 2021.
Apte, J. S., Messier, K. P., Gani, S., Brauer, M., Kirchstetter, T. W., Lunden, M. M., Marshall, J. D., Portier, C. J., Vermeulen, R. C. H., and Hamburg, S. P.: High-Resolution Air Pollution Mapping with Google Street View Cars: Exploiting Big Data, Environ. Sci. Technol., 51, 6999–7008, https://doi.org/10.1021/acs.est.7b00891, 2017.
Baldwin, N., Gilani, O., Raja, S., Batterman, S., Ganguly, R., Hopke, P., Berrocal, V., Robins, T., and Hoogterp, S.: Factors affecting pollutant concentrations in the near-road environment, Atmos. Environ., 115, 223–235, https://doi.org/10.1016/j.atmosenv.2015.05.024, 2015.
Brantley, H. L., Hagler, G. S. W., Kimbrough, E. S., Williams, R. W., Mukerjee, S., and Neas, L. M.: Mobile air monitoring data-processing strategies and effects on spatial air pollution trends, Atmos. Meas. Tech., 7, 2169–2183, https://doi.org/10.5194/amt-7-2169-2014, 2014.
Brantley, H. L., Hagler, G. S. W., Herndon, S. C., Massoli, P., Bergin, M. H., and Russell, A. G.: Characterization of Spatial Air Pollution Patterns Near a Large Railyard Area in Atlanta, Georgia, Int. J. Environ. Res. Public. Health, 16, 535, https://doi.org/10.3390/ijerph16040535, 2019.
Bukowiecki, N., Dommen, J., Prévôt, A. S. H., Richter, R., Weingartner, E., and Baltensperger, U.: A mobile pollutant measurement laboratory – measuring gas phase and aerosol ambient concentrations with high spatial and temporal resolution, Atmos. Environ., 36, 5569–5579, https://doi.org/10.1016/S1352-2310(02)00694-5, 2002.
Chambliss, S. E., Preble, C. V., Caubel, J. J., Cados, T., Messier, K. P., Alvarez, R. A., LaFranchi, B., Lunden, M., Marshall, J. D., Szpiro, A. A., Kirchstetter, T. W., and Apte, J. S.: Comparison of Mobile and Fixed-Site Black Carbon Measurements for High-Resolution Urban Pollution Mapping, Environ. Sci. Technol., 54, 7848–7857, https://doi.org/10.1021/acs.est.0c01409, 2020.
Chatzis, S. and Varvarigou, T.: A Robust to Outliers Hidden Markov Model with Application in Text-Dependent Speaker Identification, in: 2007 IEEE International Conference on Signal Processing and Communications, 24–27 November 2007, Dubai, United Arab Emirates, 804–807, https://doi.org/10.1109/ICSPC.2007.4728441, 2007.
Chatzis, S. P., Kosmopoulos, D. I., and Varvarigou, T. A.: Robust Sequential Data Modeling Using an Outlier Tolerant Hidden Markov Model, IEEE Trans. Pattern Anal. Mach. Intell., 31, 1657–1669, https://doi.org/10.1109/TPAMI.2008.215, 2009.
Dempster, A. P., Laird, N. M., and Rubin, D. B.: Maximum Likelihood from Incomplete Data Via the EM Algorithm, J. R. Stat. Soc. Ser. B Methodol., 39, 1–22, https://doi.org/10.1111/j.2517-6161.1977.tb01600.x, 1977.
Environmental Defense Fund: Google Earth Outreach, Rice University, and Sonoma Technology: Houston Mobile, OpenAQ [data set], available at: https://openaq.org/#/project/28974, last access: 18 August 2021.
Forney, G. D.: The viterbi algorithm, Proc. IEEE, 61, 268–278, https://doi.org/10.1109/PROC.1973.9030, 1973.
Gómez-Losada, Á., Santos, F. M., Gibert, K., and Pires, J. C. M.: A data science approach for spatiotemporal modelling of low and resident air pollution in Madrid (Spain): Implications for epidemiological studies, Comput. Environ. Urban Syst., 75, 1–11, https://doi.org/10.1016/j.compenvurbsys.2018.12.005, 2019.
Hankey, S. and Marshall, J. D.: Land Use Regression Models of On-Road Particulate Air Pollution (Particle Number, Black Carbon, PM2.5, Particle Size) Using Mobile Monitoring, Environ. Sci. Technol., 49, 9194–9202, https://doi.org/10.1021/acs.est.5b01209, 2015.
Hankey, S., Sforza, P., and Pierson, M.: Using Mobile Monitoring to Develop Hourly Empirical Models of Particulate Air Pollution in a Rural Appalachian Community, Environ. Sci. Technol., 53, 4305–4315, https://doi.org/10.1021/acs.est.8b05249, 2019.
Hudda, N., Gould, T., Hartin, K., Larson, T. V., and Fruin, S. A.: Emissions from an International Airport Increase Particle Number Concentrations 4-fold at 10 km Downwind, Environ. Sci. Technol., 48, 6628–6635, https://doi.org/10.1021/es5001566, 2014.
Karner, A. A., Eisinger, D. S., and Niemeier, D. A.: Near-Roadway Air Quality: Synthesizing the Findings from Real-World Data, Environ. Sci. Technol., 44, 5334–5344, https://doi.org/10.1021/es100008x, 2010.
Langrock, R., Kneib, T., Sohn, A., and DeRuiter, S. L.: Nonparametric inference in hidden Markov models using P-splines, Biometrics, 71, 520–528, https://doi.org/10.1111/biom.12282, 2015.
Langrock, R., Adam, T., Leos-Barajas, V., Mews, S., Miller, D. L., and Papastamatiou, Y. P.: Spline-based nonparametric inference in general state-switching models, Stat. Neerlandica, 72, 179–200, https://doi.org/10.1111/stan.12133, 2018.
Larson, T., Gould, T., Riley, E. A., Austin, E., Fintzi, J., Sheppard, L., Yost, M., and Simpson, C.: Ambient air quality measurements from a continuously moving mobile platform: Estimation of area-wide, fuel-based, mobile source emission factors using absolute principal component scores, Atmos. Environ., 152, 201–211, https://doi.org/10.1016/j.atmosenv.2016.12.037, 2017.
Li, H. Z., Gu, P., Ye, Q., Zimmerman, N., Robinson, E. S., Subramanian, R., Apte, J. S., Robinson, A. L., and Presto, A. A.: Spatially dense air pollutant sampling: Implications of spatial variability on the representativeness of stationary air pollutant monitors, Atmos. Environ., 2, 100012, https://doi.org/10.1016/j.aeaoa.2019.100012, 2019.
Luke, W. T., Kelley, P., Lefer, B. L., Flynn, J., Rappenglück, B., Leuchner, M., Dibb, J. E., Ziemba, L. D., Anderson, C. H., and Buhr, M.: Measurements of primary trace gases and NOY composition in Houston, Texas, Atmos. Environ., 44, 4068–4080, https://doi.org/10.1016/j.atmosenv.2009.08.014, 2010.
Messier, K. P., Chambliss, S. E., Gani, S., Alvarez, R., Brauer, M., Choi, J. J., Hamburg, S. P., Kerckhoffs, J., LaFranchi, B., Lunden, M. M., Marshall, J. D., Portier, C. J., Roy, A., Szpiro, A. A., Vermeulen, R. C. H., and Apte, J. S.: Mapping Air Pollution with Google Street View Cars: Efficient Approaches with Mobile Monitoring and Land Use Regression, Environ. Sci. Technol., 52, 12563–12572, https://doi.org/10.1021/acs.est.8b03395, 2018.
Miller, D. J., Actkinson, B., Padilla, L., Griffin, R. J., Moore, K., Lewis, P. G. T., Gardner-Frolick, R., Craft, E., Portier, C. J., Hamburg, S. P., and Alvarez, R. A.: Characterizing Elevated Urban Air Pollutant Spatial Patterns with Mobile Monitoring in Houston, Texas, Environ. Sci. Technol., 54, 2133–2142, https://doi.org/10.1021/acs.est.9b05523, 2020.
Patton, A. P., Perkins, J., Zamore, W., Levy, J. I., Brugge, D., and Durant, J. L.: Spatial and temporal differences in traffic-related air pollution in three urban neighborhoods near an interstate highway, Atmos. Environ., 99, 309–321, https://doi.org/10.1016/j.atmosenv.2014.09.072, 2014.
R: The R Project for Statistical Computing, available at: https://www.r-project.org/, last access: 22 June 2021.
Robinson, E. S., Gu, P., Ye, Q., Li, H. Z., Shah, R. U., Apte, J. S., Robinson, A. L., and Presto, A. A.: Restaurant Impacts on Outdoor Air Quality: Elevated Organic Aerosol Mass from Restaurant Cooking with Neighborhood-Scale Plume Extents, Environ. Sci. Technol., 52, 9285–9294, https://doi.org/10.1021/acs.est.8b02654, 2018.
Seinfeld, J. H. and Pandis, S. N.: Atmospheric Chemistry and Physics: From Air Pollution to Climate Change, John Wiley & Sons, Hoboken, New Jersey, USA, 1146 pp., 2016.
Svensén, M. and Bishop, C. M.: Robust Bayesian mixture modelling, Neurocomputing, 64, 235–252, https://doi.org/10.1016/j.neucom.2004.11.018, 2005.
Tessum, M. W., Larson, T., Gould, T. R., Simpson, C. D., Yost, M. G., and Vedal, S.: Mobile and Fixed-Site Measurements To Identify Spatial Distributions of Traffic-Related Pollution Sources in Los Angeles, Environ. Sci. Technol., 52, 2844–2853, https://doi.org/10.1021/acs.est.7b04889, 2018.
TIGER/Line Shapefile: Harris County, TX, All Roads County-based Shapefile, available at: https://catalog.data.gov/dataset/tiger-line-shapefile-2018-county-harris-county-tx-all-roads-county-based-shapefile (last access: 19 October 2020), 2018.
Van den Bossche, J., Peters, J., Verwaeren, J., Botteldooren, D., Theunis, J., and De Baets, B.: Mobile monitoring for mapping spatial variation in urban air quality: Development and validation of a methodology based on an extensive dataset, Atmos. Environ., 105, 148–161, https://doi.org/10.1016/j.atmosenv.2015.01.017, 2015.
Visser, I. and Speekenbrink, M.: depmixS4: An R Package for Hidden Markov Models, J. Stat. Softw., 36, 1–21, https://doi.org/10.18637/jss.v036.i07, 2010.
Zhang, X., Chen, X., and Zhang, X.: The impact of exposure to air pollution on cognitive performance, Proc. Natl. Acad. Sci. USA, 115, 9193–9197, https://doi.org/10.1073/pnas.1809474115, 2018.
This paper describes the development of a new method used to estimate background from mobile monitoring time series. The method is tested on a previously published dataset, applied to an extensive mobile dataset, and compared with other previously published techniques used to estimate background. The results suggest that the method is a promising framework for background estimation.
This paper describes the development of a new method used to estimate background from mobile...