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Nanofibre filters may offer new properties not available in commercial fibre filters. These include a higher surface area and the ability to include novel materials within the fibres. In addition the small size allows potential gains in performance due to the slip-flow phenomenon in which normal gas viscosity does not apply to objects smaller than the mean free path of the gas. We tested the properties of novel electrospun fibre filters generated from polyvinyl alcohol solutions, optionally embedded with nano-grains of photocatalytic TiO2 and activated charcoal. The tested materials exhibited pressure drops in the range of 195 Pa to 2693 Pa for a face velocity of 5.3 cm/s and a removal efficiency greater than 97% for 12–480 nm particles. Basis weights for the filters ranged from 16.6 to 67.6 g/m2 and specific surface areas ranged from 1.4 to 17.4 m2/g. Reactivity towards volatile organic compounds (VOCs) was achieved by irradiating the photocatalytic filters with ultraviolet light. It is necessary to solve the problems connected to the absorbance of VOCs and further reduce the resistance to airflow in order for these filters to achieve widespread use. The incorporation of reactive air filtration into building ventilation systems will contribute to improved indoor air quality.
Roberta Orlando; Merve Polat; Alireza Afshari; Matthew Johnson; Peter Fojan. Electrospun Nanofibre Air Filters for Particles and Gaseous Pollutants. Sustainability 2021, 13, 6553 .
AMA StyleRoberta Orlando, Merve Polat, Alireza Afshari, Matthew Johnson, Peter Fojan. Electrospun Nanofibre Air Filters for Particles and Gaseous Pollutants. Sustainability. 2021; 13 (12):6553.
Chicago/Turabian StyleRoberta Orlando; Merve Polat; Alireza Afshari; Matthew Johnson; Peter Fojan. 2021. "Electrospun Nanofibre Air Filters for Particles and Gaseous Pollutants." Sustainability 13, no. 12: 6553.
Photocatalysts promised to control pollution in an environmentally benign manner, inexpensively, and with a low or cheap energy input. However, the limited chemical activity of photocatalysts has prevented their widespread use. This limitation has two important consequences; in addition to limited removal efficiency for pollution, photocatalysts may also generate unwanted byproducts due to incomplete reaction. This study focuses on the byproducts formed in the photocatalytic degradation of dimethyl sulfide (DMS) on titanium dioxide (TiO2), using a continuous flow reactor and detection via proton transfer reaction mass spectrometry. TiO2, activated carbon (AC), TiO2/AC (1:1) and TiO2/AC (1:5) were tested using either a laser-driven light source or LED lamps at 365 nm. The samples were characterized using a N2-BET surface area and pore size distributions, Scanning Electron Microscopy, X-ray Diffraction, and X-ray Photoelectron Spectroscopy, which confirmed that TiO2 was successfully coated on activated carbon without unexpected phases. TiO2 and activated carbon showed different removal mechanisms for DMS. The maximum yield of formaldehyde, 11.4%, was observed for DMS reacting on a TiO2/AC (1:5) composite operating at a DMS removal efficiency of 31.7% at 50
Weijia Yu; Marten In `t Veld; Rossana Bossi; Mohamed Ateia; Dominique Tobler; Anders Feilberg; Nicolas Bovet; Matthew Johnson. Formation of Formaldehyde and Other Byproducts by TiO2 Photocatalyst Materials. Sustainability 2021, 13, 4821 .
AMA StyleWeijia Yu, Marten In `t Veld, Rossana Bossi, Mohamed Ateia, Dominique Tobler, Anders Feilberg, Nicolas Bovet, Matthew Johnson. Formation of Formaldehyde and Other Byproducts by TiO2 Photocatalyst Materials. Sustainability. 2021; 13 (9):4821.
Chicago/Turabian StyleWeijia Yu; Marten In `t Veld; Rossana Bossi; Mohamed Ateia; Dominique Tobler; Anders Feilberg; Nicolas Bovet; Matthew Johnson. 2021. "Formation of Formaldehyde and Other Byproducts by TiO2 Photocatalyst Materials." Sustainability 13, no. 9: 4821.
The performance of photocatalytic advanced oxidation must be improved in order for the technology to make the jump from academic research to widespread use. Research is needed on the factors that cause photocatalysis to become self-limiting. In this study, we introduced, for the first time, nanobubbles continuously into a running photocatalytic reactor. Synthetic air, O2, and N2 bubbles in the size range of 40 to 700 nm were added to a reaction system comprising P25 TiO2 photocatalyst in stirred aqueous solution excited by UV-A lamps, with methyl orange as a target contaminant. The removal of methyl orange was tested under conditions of changing pH and with the addition of different radical scavengers. Results indicated that the oxygen and air nanobubbles improved the photocatalytic degradation of methyl orange—the removal efficiency of methyl orange increased from 58.2 ± 3.5% (N2 aeration) to 71.9 ± 0.6% (O2 aeration). Dissolved oxygen (DO) of 14.93 ± 0.13 mg/L was achieved using O2 nanobubbles in comparison to 8.43 ± 0.34 mg/L without aeration. The photodegradation of methyl orange decreased from 70.8 ± 0.4% to 53.9 ± 0.5% as pH increased from 2 to 10. Experiments using the scavengers showed that O2 − was the main reactive species in photocatalytic degradation under highly dissolved oxygen conditions, which also accounted for the observation that the removal efficiency for methyl orange decreased at higher pH. However, without photocatalyst, nanobubbles alone did not improve the removal of methyl orange, and nanobubbles also did not increase the degradation of methyl orange by only photolysis. These experiments show that oxygen and air nanobubbles can act as environmentally friendly catalysts for boosting the performance of photocatalytic water treatment systems.
Weijia Yu; Jiaying Chen; Mohamed Ateia; Ezra Cates; Matthew Johnson. Do Gas Nanobubbles Enhance Aqueous Photocatalysis? Experiment and Analysis of Mechanism. Catalysts 2021, 11, 511 .
AMA StyleWeijia Yu, Jiaying Chen, Mohamed Ateia, Ezra Cates, Matthew Johnson. Do Gas Nanobubbles Enhance Aqueous Photocatalysis? Experiment and Analysis of Mechanism. Catalysts. 2021; 11 (4):511.
Chicago/Turabian StyleWeijia Yu; Jiaying Chen; Mohamed Ateia; Ezra Cates; Matthew Johnson. 2021. "Do Gas Nanobubbles Enhance Aqueous Photocatalysis? Experiment and Analysis of Mechanism." Catalysts 11, no. 4: 511.
The development of laser spectroscopy has made it possible to measure minute changes in the concentrations of trace gases and their isotopic analogs. These single or even multiply substituted species occur at ratios from per cent to sub-ppm and contain important information concerning trace gas sources and transformations. Due to their low abundance minimizing spectral interference from other gases in a mixture is essential. Options including traps and membranes are available to remove many specific impurities. Methods for removing CH4 , however, are extremely limited as methane has low reactivity and adsorbs poorly to most materials. Here we demonstrate a novel method for CH4 removal via chlorine-initiated oxidation. Our motivation in developing the technique was to overcome methane interference in measurements of N2O isotopic analogs when using a cavity ring-down spectrometer. We describe the design and validation of a proof-of-concept device and a kinetic model to predict the dependence of the methane removal efficiency on methane concentration [CH4], chlorine photolysis rate JCl2, chlorine concentration [Cl2], and residence time tR. The model was validated by comparison to experimental data and then used to predict the possible formation of troublesome side- and by-products including CCl4 and HCl. The removal of methane could be maintained with a peak removal efficiency > 98 % for ambient levels of methane at a flow rate of 7.5 ml min−1 with [Cl2] at 50 ppm. These tests show that our method is a viable option for continuous methane scrubbing. Additional measures may be needed to avoid complications due to the introduction of Cl2 and formation of HCl. Note that the method will also oxidize most other common volatile organic compounds. The system was tested in combination with a cavity ring-down methane spectrometer, and the developed method was shown to be successful at removing methane interference.
Merve Polat; Jesper Baldtzer Liisberg; Morten Krogsbøll; Thomas Blunier; Matthew S. Johnson. Photochemical method for removing methane interference for improved gas analysis. 2021, 2021, 1 -46.
AMA StyleMerve Polat, Jesper Baldtzer Liisberg, Morten Krogsbøll, Thomas Blunier, Matthew S. Johnson. Photochemical method for removing methane interference for improved gas analysis. . 2021; 2021 ():1-46.
Chicago/Turabian StyleMerve Polat; Jesper Baldtzer Liisberg; Morten Krogsbøll; Thomas Blunier; Matthew S. Johnson. 2021. "Photochemical method for removing methane interference for improved gas analysis." 2021, no. : 1-46.
Interfacial regions are unique chemical reaction environments that can promote chemistry not found elsewhere. The air–water interface is ubiquitous in the natural environment in the form of ocean surfaces and aqueous atmospheric aerosols. Here we investigate the chemistry and photochemistry of pyruvic acid (PA), a common environmental species, at the air–water interface and compare it to its aqueous bulk chemistry using two different experimental setups: (1) a Langmuir–Blodgett trough, which models natural water surfaces and provides a direct comparison between the two reaction environments, and (2) an atmospheric simulation chamber (CESAM) to monitor the chemical processing of nebulized aqueous PA droplets. The results show that surface chemistry leads to substantial oligomer formation. The sequence begins with the condensation of lactic acid (LA), formed at the surface, with itself and with pyruvic acid, and LA + LA – H2O and LA + PA – H2O are prominent among the products in addition to a series of higher-molecular-weight oligomers of mixed units of PA and LA. In addition, we see zymonic acid at the surface. Actinic radiation enhances the production of the oligomers and produces additional surface-active molecules known from the established aqueous photochemical mechanisms. The presence and formation of complex organic molecules at the air–water interface from a simple precursor like PA in the natural environment is relevant to contemporary atmospheric science and is important in the context of prebiotic chemistry, where abiotic production of complex molecules is necessary for abiogenesis.
Keaten J. Kappes; Alexandra M. Deal; Malte F. Jespersen; Sandra L. Blair; Jean-Francois Doussin; Mathieu Cazaunau; Edouard Pangui; Brianna N. Hopper; Matthew S. Johnson; Veronica Vaida. Chemistry and Photochemistry of Pyruvic Acid at the Air–Water Interface. The Journal of Physical Chemistry A 2021, 125, 1036 -1049.
AMA StyleKeaten J. Kappes, Alexandra M. Deal, Malte F. Jespersen, Sandra L. Blair, Jean-Francois Doussin, Mathieu Cazaunau, Edouard Pangui, Brianna N. Hopper, Matthew S. Johnson, Veronica Vaida. Chemistry and Photochemistry of Pyruvic Acid at the Air–Water Interface. The Journal of Physical Chemistry A. 2021; 125 (4):1036-1049.
Chicago/Turabian StyleKeaten J. Kappes; Alexandra M. Deal; Malte F. Jespersen; Sandra L. Blair; Jean-Francois Doussin; Mathieu Cazaunau; Edouard Pangui; Brianna N. Hopper; Matthew S. Johnson; Veronica Vaida. 2021. "Chemistry and Photochemistry of Pyruvic Acid at the Air–Water Interface." The Journal of Physical Chemistry A 125, no. 4: 1036-1049.
There is strong interest in using isotopic analysis to better constrain the budget of atmospheric nitrous oxide (N2O). This interest is supported by emerging instruments that allow analysis of multiply substituted species. We have studied fractionation during UV photolysis of singly and doubly isotopically substituted molecules (isotopocules) of N2O. N2O was photolyzed in an electropolished stainless-steel reactor using a broadband laser-driven light source with bandpass filters. Isotopocule ratios were quantified at different stages of photolysis using a quantum cascade laser absorption spectroscopy (QCLAS) system. Wavelength-dependent fractionation constants were determined using the Rayleigh distillation model. The fractionation constants for photolysis with 200 nm and 214 nm bandpass filters, respectively, for the seven most abundant isotopocules of N2O (after 14N14N16O) are: 14N15N16O (456): (−48.9 ± 7.4) ‰ /(−82.4 ± 22.3) ‰, 15N14N16O (546): (−22.2 ± 5.3) ‰ /(−36.1 ± 19.6) ‰, 14N14N17O (447): (−12.7 ± 4.5) ‰ /(−21.9 ± 15.7) ‰, 14N14N18O (448): (−33.5 ± 12.0) ‰ /(−44.1 ± 29.8) ‰, 14N15N18O (458): (−80.9 ± 6.5) ‰ /(−120.9 ± 23.7) ‰, 15N14N18O (548): (−52.7 ± 10.8) ‰ /(−79.1 ± 28.5) ‰, 15N15N16O (556): (−66.9 ± 9.8) ‰ /(−110.9 ± 27.5) ‰. The fractionation constants determined here for isotopocules 456, 546, 447, 448, and 556 are in agreement with previous theoretical models employed in this study and previous experiments. For 458 and 548, the fractionation constants were determined for the first time, confirming the prediction of more negative fractionation for 15N substitution in the central position. The effect of stratospheric photolysis on the clumped isotope Δ values of tropospheric N2O was found to be modest with Δ458 = (4.0 ± 1.0) ‰, Δ548 = (−4.0 ± 1.0) ‰, and Δ556 = (−1.5 ± 1.0) ‰ at 9% photolysis. Therefore, atmospheric variations of doubly substituted N2O isotopocules will likely be dominated by the characteristics of the N2O sources, which strongly supports their value for source attribution and quantification.
Kristýna Kantnerová; Malte F. Jespersen; Stefano M. Bernasconi; Lukas Emmenegger; Matthew S. Johnson; Joachim Mohn. Photolytic fractionation of seven singly and doubly substituted nitrous oxide isotopocules measured by quantum cascade laser absorption spectroscopy. Atmospheric Environment: X 2020, 8, 100094 .
AMA StyleKristýna Kantnerová, Malte F. Jespersen, Stefano M. Bernasconi, Lukas Emmenegger, Matthew S. Johnson, Joachim Mohn. Photolytic fractionation of seven singly and doubly substituted nitrous oxide isotopocules measured by quantum cascade laser absorption spectroscopy. Atmospheric Environment: X. 2020; 8 ():100094.
Chicago/Turabian StyleKristýna Kantnerová; Malte F. Jespersen; Stefano M. Bernasconi; Lukas Emmenegger; Matthew S. Johnson; Joachim Mohn. 2020. "Photolytic fractionation of seven singly and doubly substituted nitrous oxide isotopocules measured by quantum cascade laser absorption spectroscopy." Atmospheric Environment: X 8, no. : 100094.
Szymon Kwiatkowski; Merve Polat; Weijia Yu; Matthew Stanley Johnson. Industrial Emissions Control Technologies: Introduction. Air Pollution Sources, Statistics and Health Effects 2020, 477 -511.
AMA StyleSzymon Kwiatkowski, Merve Polat, Weijia Yu, Matthew Stanley Johnson. Industrial Emissions Control Technologies: Introduction. Air Pollution Sources, Statistics and Health Effects. 2020; ():477-511.
Chicago/Turabian StyleSzymon Kwiatkowski; Merve Polat; Weijia Yu; Matthew Stanley Johnson. 2020. "Industrial Emissions Control Technologies: Introduction." Air Pollution Sources, Statistics and Health Effects , no. : 477-511.
Mohsen Rezaei; Matthew Stanley Johnson. Airborne Nanoparticles: Control and Detection. Air Pollution Sources, Statistics and Health Effects 2020, 85 -133.
AMA StyleMohsen Rezaei, Matthew Stanley Johnson. Airborne Nanoparticles: Control and Detection. Air Pollution Sources, Statistics and Health Effects. 2020; ():85-133.
Chicago/Turabian StyleMohsen Rezaei; Matthew Stanley Johnson. 2020. "Airborne Nanoparticles: Control and Detection." Air Pollution Sources, Statistics and Health Effects , no. : 85-133.
Louise Bøge Frederickson; Emma Amalie Petersen-Sonn; Yuwei Shen; Ole Hertel; Youwei Hong; Johan Schmidt; Matthew Stanley Johnson. Low-Cost Sensors for Indoor and Outdoor Pollution. Air Pollution Sources, Statistics and Health Effects 2020, 423 -453.
AMA StyleLouise Bøge Frederickson, Emma Amalie Petersen-Sonn, Yuwei Shen, Ole Hertel, Youwei Hong, Johan Schmidt, Matthew Stanley Johnson. Low-Cost Sensors for Indoor and Outdoor Pollution. Air Pollution Sources, Statistics and Health Effects. 2020; ():423-453.
Chicago/Turabian StyleLouise Bøge Frederickson; Emma Amalie Petersen-Sonn; Yuwei Shen; Ole Hertel; Youwei Hong; Johan Schmidt; Matthew Stanley Johnson. 2020. "Low-Cost Sensors for Indoor and Outdoor Pollution." Air Pollution Sources, Statistics and Health Effects , no. : 423-453.
Jiaying Chen; Mie Jul Dahlin; Linnea Luuppala; David Bickford; Lina Boljka; Vanessa Burns; Matthew Stanley Johnson. Air Pollution and Climate Change: Sustainability, Restoration, and Ethical Implications. Air Pollution Sources, Statistics and Health Effects 2020, 279 -325.
AMA StyleJiaying Chen, Mie Jul Dahlin, Linnea Luuppala, David Bickford, Lina Boljka, Vanessa Burns, Matthew Stanley Johnson. Air Pollution and Climate Change: Sustainability, Restoration, and Ethical Implications. Air Pollution Sources, Statistics and Health Effects. 2020; ():279-325.
Chicago/Turabian StyleJiaying Chen; Mie Jul Dahlin; Linnea Luuppala; David Bickford; Lina Boljka; Vanessa Burns; Matthew Stanley Johnson. 2020. "Air Pollution and Climate Change: Sustainability, Restoration, and Ethical Implications." Air Pollution Sources, Statistics and Health Effects , no. : 279-325.
Freja Hasager; Joachim Dithmer Bjerregaard; James Bonomaully; Hasse Knap; Alireza Afshari; Matthew Stanley Johnson. Indoor Air Quality: Status and Standards. Air Pollution Sources, Statistics and Health Effects 2020, 135 -162.
AMA StyleFreja Hasager, Joachim Dithmer Bjerregaard, James Bonomaully, Hasse Knap, Alireza Afshari, Matthew Stanley Johnson. Indoor Air Quality: Status and Standards. Air Pollution Sources, Statistics and Health Effects. 2020; ():135-162.
Chicago/Turabian StyleFreja Hasager; Joachim Dithmer Bjerregaard; James Bonomaully; Hasse Knap; Alireza Afshari; Matthew Stanley Johnson. 2020. "Indoor Air Quality: Status and Standards." Air Pollution Sources, Statistics and Health Effects , no. : 135-162.
Formaldehyde (HCHO) and nitrogen dioxide (NO2) often co-exist in urban environments at levels that are hazardous to health. There is a demand for a solution to the problem of their combined removal. In this paper, we investigate catalysts, adsorbents and composites for their removal efficiency (RE) toward HCHO and NO2, in the context of creating a pollution control device (PCD). Proton-transfer-reaction mass spectrometry and cavity ring-down spectrometry are used to measure HCHO, and chemiluminescence and absorbance-based monitors for NO2. Commercially available and lab-synthesized materials are tested under relevant conditions. None of the commercial adsorbents are effective for HCHO removal, whereas two metal oxide-based catalysts are highly effective, with REs of 81 ± 4% and 82 ± 1%, an improvement on previous materials tested under similar conditions. The best performing material for combined removal is a novel composite consisting of a noble metal catalyst supported on a metal oxide, combined with a treated active carbon adsorbent. The composite is theorized to work synergistically to physisorb and oxidize HCHO and chemisorb NO2. It has an HCHO RE of 72 ± 2% and an NO2 RE of 96 ± 2%. This material has potential as the active component in PCDs used to reduce personal pollution exposure.
Hugo S. Russell; James Bonomaully; Rossana Bossi; Magdalena E. G. Hofmann; Hasse C. Knap; Jakob B. Pernov; Marten In ‘T Veld; Matthew S. Johnson. Novel Materials for Combined Nitrogen Dioxide and Formaldehyde Pollution Control under Ambient Conditions. Catalysts 2020, 10, 1040 .
AMA StyleHugo S. Russell, James Bonomaully, Rossana Bossi, Magdalena E. G. Hofmann, Hasse C. Knap, Jakob B. Pernov, Marten In ‘T Veld, Matthew S. Johnson. Novel Materials for Combined Nitrogen Dioxide and Formaldehyde Pollution Control under Ambient Conditions. Catalysts. 2020; 10 (9):1040.
Chicago/Turabian StyleHugo S. Russell; James Bonomaully; Rossana Bossi; Magdalena E. G. Hofmann; Hasse C. Knap; Jakob B. Pernov; Marten In ‘T Veld; Matthew S. Johnson. 2020. "Novel Materials for Combined Nitrogen Dioxide and Formaldehyde Pollution Control under Ambient Conditions." Catalysts 10, no. 9: 1040.
In this pilot study, low-cost air pollution sensor nodes were fitted in waste removal trucks, hospital vans and taxis to record drivers’ exposure to air pollution in Central London. Particulate matter (PM 2 . 5 and PM 10 ), CO 2 , NO 2 , temperature and humidity were recorded in real-time with nodes containing low-cost sensors, an electrochemical gas sensor for NO 2 , an optical particle counter for PM 2 . 5 and PM 10 and a non-dispersive infrared (NDIR) sensor for CO 2 , temperature and relative humidity. An intervention using a pollution filter to trap PM and NO 2 was also evaluated. The measurements were compared with urban background and roadside monitoring stations at Honor Oak Park and Marylebone Road, respectively. The vehicle records show PM and NO 2 concentrations similar to Marylebone Road and a higher NO 2 -to-PM ratio than at Honor Oak Park. Drivers are exposed to elevated pollution levels relative to Honor Oak Park: 1.72 μ g m − 3 , 1.92 μ g m − 3 and 58.38 ppb for PM 2 . 5 , PM 10 , and NO 2 , respectively. The CO 2 levels ranged from 410 to over 4000 ppm. There is a significant difference in average concentrations of PM 2 . 5 and PM 10 between the vehicle types and a non-significant difference in the average concentrations measured with and without the pollution filter within the sectors. In conclusion, drivers face elevated air pollution exposure as part of their jobs.
Louise Frederickson; Shanon Lim; Hugo Russell; Szymon Kwiatkowski; James Bonomaully; Johan Schmidt; Ole Hertel; Ian Mudway; Benjamin Barratt; Matthew Johnson. Monitoring Excess Exposure to Air Pollution for Professional Drivers in London Using Low-Cost Sensors. Atmosphere 2020, 11, 749 .
AMA StyleLouise Frederickson, Shanon Lim, Hugo Russell, Szymon Kwiatkowski, James Bonomaully, Johan Schmidt, Ole Hertel, Ian Mudway, Benjamin Barratt, Matthew Johnson. Monitoring Excess Exposure to Air Pollution for Professional Drivers in London Using Low-Cost Sensors. Atmosphere. 2020; 11 (7):749.
Chicago/Turabian StyleLouise Frederickson; Shanon Lim; Hugo Russell; Szymon Kwiatkowski; James Bonomaully; Johan Schmidt; Ole Hertel; Ian Mudway; Benjamin Barratt; Matthew Johnson. 2020. "Monitoring Excess Exposure to Air Pollution for Professional Drivers in London Using Low-Cost Sensors." Atmosphere 11, no. 7: 749.
Air pollution “is the presence in the outdoor atmosphere of any one or more substances in quantities which are or may be harmful or injurious to human health or welfare, animal or plant life or...
Mohsen Rezaei; Matthew S. Johnson. Airborne Nanoparticles: Control and Detection. Encyclopedia of Sustainability Science and Technology 2020, 1 -49.
AMA StyleMohsen Rezaei, Matthew S. Johnson. Airborne Nanoparticles: Control and Detection. Encyclopedia of Sustainability Science and Technology. 2020; ():1-49.
Chicago/Turabian StyleMohsen Rezaei; Matthew S. Johnson. 2020. "Airborne Nanoparticles: Control and Detection." Encyclopedia of Sustainability Science and Technology , no. : 1-49.
The isotopic composition of nitrous oxide (N2O) provides useful information for evaluating N2O sources and budgets. Due to the co‐occurrence of multiple N2O transformation pathways, it is, however, challenging to use isotopic information to quantify the contribution of distinct processes across variable spatiotemporal scales. Here, we present an overview of recent progress in N2O isotopic studies and provide suggestions for future research, mainly focusing on: analytical techniques; production and consumption processes; and interpretation and modelling approaches. Comparing isotope‐ratio mass spectrometry (IRMS) with laser absorption spectroscopy (LAS), we conclude that IRMS is a precise technique for laboratory analysis of N2O isotopes, while LAS is more suitable for in situ /inline studies and offers advantages for site‐specific analyses. When reviewing the link between the N2O isotopic composition and underlying mechanisms/processes, we find that at the molecular scale, the specific enzymes and mechanisms involved determine isotopic fractionation effects. In contrast, at plot‐to‐global scales, mixing of N2O derived from different processes and their isotopic variability must be considered. We also find that dual isotope plots are effective for semi‐quantitative attribution of co‐occurring N2O production and reduction processes. More recently, process‐based N2O isotopic models have been developed for natural‐abundance and 15N‐tracing studies, and have been shown to be effective, particularly for data with adequate temporal resolution. Despite the significant progress made over the last decade, there is still great need and potential for future work, including development of analytical techniques, reference materials and inter‐laboratory comparisons, further exploration of N2O formation and destruction mechanisms, more observations across scales, and design and validation of interpretation and modelling approaches. Synthesizing all these efforts, we are confident that the N2O isotope community will continue to advance our understanding of N2O transformation processes in all spheres of the Earth, and in turn to gain improved constraints on regional and global budgets.
Longfei Yu; Eliza Harris; Dominika Lewicka‐Szczebak; Matti Barthel; Margareta R.A. Blomberg; Stephen J. Harris; Matthew S. Johnson; Moritz F. Lehmann; Jesper Liisberg; Christoph Müller; Nathaniel E. Ostrom; Johan Six; Sakae Toyoda; Naohiro Yoshida; Joachim Mohn. What can we learn from N 2 O isotope data? – Analytics, processes and modelling. Rapid Communications in Mass Spectrometry 2020, 34, 1 .
AMA StyleLongfei Yu, Eliza Harris, Dominika Lewicka‐Szczebak, Matti Barthel, Margareta R.A. Blomberg, Stephen J. Harris, Matthew S. Johnson, Moritz F. Lehmann, Jesper Liisberg, Christoph Müller, Nathaniel E. Ostrom, Johan Six, Sakae Toyoda, Naohiro Yoshida, Joachim Mohn. What can we learn from N 2 O isotope data? – Analytics, processes and modelling. Rapid Communications in Mass Spectrometry. 2020; 34 (20):1.
Chicago/Turabian StyleLongfei Yu; Eliza Harris; Dominika Lewicka‐Szczebak; Matti Barthel; Margareta R.A. Blomberg; Stephen J. Harris; Matthew S. Johnson; Moritz F. Lehmann; Jesper Liisberg; Christoph Müller; Nathaniel E. Ostrom; Johan Six; Sakae Toyoda; Naohiro Yoshida; Joachim Mohn. 2020. "What can we learn from N 2 O isotope data? – Analytics, processes and modelling." Rapid Communications in Mass Spectrometry 34, no. 20: 1.
Adaptation An adaptation is an adjustment made in response to an actual or expected climate that moderates or avoids harmful impacts. Adaptation can be divided into incremental and transformational...
Jiaying Chen; Mie Jul Dahlin; Linnea Luuppala; David Bickford; Lina Boljka; Vanessa Burns; Matthew S. Johnson. Air Pollution and Climate Change: Sustainability, Restoration, and Ethical Implications. Encyclopedia of Sustainability Science and Technology 2020, 1 -48.
AMA StyleJiaying Chen, Mie Jul Dahlin, Linnea Luuppala, David Bickford, Lina Boljka, Vanessa Burns, Matthew S. Johnson. Air Pollution and Climate Change: Sustainability, Restoration, and Ethical Implications. Encyclopedia of Sustainability Science and Technology. 2020; ():1-48.
Chicago/Turabian StyleJiaying Chen; Mie Jul Dahlin; Linnea Luuppala; David Bickford; Lina Boljka; Vanessa Burns; Matthew S. Johnson. 2020. "Air Pollution and Climate Change: Sustainability, Restoration, and Ethical Implications." Encyclopedia of Sustainability Science and Technology , no. : 1-48.
Computational results suggest that significant differences in the optical properties of nitrate ion pairs could explain the experimentally observed salt-specific effect of adding different salts to a solution of KNO3 on the n→π* absorption.
Pernille D. Pedersen; Kurt V. Mikkelsen; Matthew S. Johnson. The unexpected effect of aqueous ion pairs on the forbidden n → π* transition in nitrate. Physical Chemistry Chemical Physics 2020, 22, 11678 -11685.
AMA StylePernille D. Pedersen, Kurt V. Mikkelsen, Matthew S. Johnson. The unexpected effect of aqueous ion pairs on the forbidden n → π* transition in nitrate. Physical Chemistry Chemical Physics. 2020; 22 (20):11678-11685.
Chicago/Turabian StylePernille D. Pedersen; Kurt V. Mikkelsen; Matthew S. Johnson. 2020. "The unexpected effect of aqueous ion pairs on the forbidden n → π* transition in nitrate." Physical Chemistry Chemical Physics 22, no. 20: 11678-11685.
Airborne particulate matter (PM) exposure has been identified as a key environmental risk factor, associated especially with diseases of the respiratory and cardiovascular system and with almost 9 million premature deaths per year. Low-cost optical sensors for PM measurement are desirable for monitoring exposure closer to the personal level and particularly suited for developing spatiotemporally dense city sensor networks. However, questions remain over the accuracy and reliability of the data they produce, particularly regarding the influence of environmental parameters such as humidity and temperature, and with varying PM sources and concentration profiles. In this study, eight units each of five different models of commercially available low-cost optical PM sensors (40 individual sensors in total) were tested under controlled laboratory conditions, against higher-grade instruments for: lower limit of detection, response time, responses to sharp pollution spikes lasting
Florentin Michel Jacques Bulot; Hugo Savill Russell; Mohsen Rezaei; Matthew Stanley Johnson; Steven James Johnston Ossont; Andrew Kevin Richard Morris; Philip James Basford; Natasha Hazel Celeste Easton; Gavin Lee Foster; Matthew Loxham; Simon James Cox. Laboratory Comparison of Low-Cost Particulate Matter Sensors to Measure Transient Events of Pollution. Sensors 2020, 20, 2219 .
AMA StyleFlorentin Michel Jacques Bulot, Hugo Savill Russell, Mohsen Rezaei, Matthew Stanley Johnson, Steven James Johnston Ossont, Andrew Kevin Richard Morris, Philip James Basford, Natasha Hazel Celeste Easton, Gavin Lee Foster, Matthew Loxham, Simon James Cox. Laboratory Comparison of Low-Cost Particulate Matter Sensors to Measure Transient Events of Pollution. Sensors. 2020; 20 (8):2219.
Chicago/Turabian StyleFlorentin Michel Jacques Bulot; Hugo Savill Russell; Mohsen Rezaei; Matthew Stanley Johnson; Steven James Johnston Ossont; Andrew Kevin Richard Morris; Philip James Basford; Natasha Hazel Celeste Easton; Gavin Lee Foster; Matthew Loxham; Simon James Cox. 2020. "Laboratory Comparison of Low-Cost Particulate Matter Sensors to Measure Transient Events of Pollution." Sensors 20, no. 8: 2219.
Environmental contextThe fresh pleasant smell of laundry dried outside in sunlight is recognised by most people, but despite decades of speculation the origin of the smell has not been demonstrated. We show that the smell of line-dried laundry is due to the unique combination of traces of atmospheric hydrocarbons, sunlight and a wet fabric surface. This surface photochemistry is likely to be widespread in the environment on surfaces of natural materials. AbstractIn this study, we find that the drying method is the key element in generating the well-known fresh scent of line-dried laundry, which we argue demonstrates that it is the result of physical and chemical processes occurring on the surface of the fabric. Cotton towels were rinsed with Milli-Q water and dried outdoors, indoors, and outdoors but not exposed to sunlight. The dried towels were placed in sealed Tedlar bags, and the emitted compounds were analysed by using thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS) to yield qualitative gas chromatograms and mass spectra. We observed a variety of C5 to C9 oxidised carbon compounds (e.g. aldehydes such as pentanal, hexanal, heptanal, octanal, and nonanal) when the towels were dried outside. These compounds are not observed in the other conditions. Many of these compounds have smells that are subjectively found to be pleasant. The experiments indicate that both UV light and the presence of liquid water are necessary to generate the products. The polar nature of the oxidised compounds may explain why the smell of fresh laundry is relatively long-lasting because hydrogen bonds can form between these compounds and cotton fibres. We therefore propose that oxidative photochemistry on the surface of the drying laundry is responsible for the production of the fresh smell.
Silvia Pugliese; Malte Frydenlund Jespersen; Jakob Boyd Pernov; Justin Shenolikar; Jesper Nygaard; Ole John Nielsen; Matthew S. Johnson. Chemical analysis and origin of the smell of line-dried laundry. Environmental Chemistry 2020, 17, 355 .
AMA StyleSilvia Pugliese, Malte Frydenlund Jespersen, Jakob Boyd Pernov, Justin Shenolikar, Jesper Nygaard, Ole John Nielsen, Matthew S. Johnson. Chemical analysis and origin of the smell of line-dried laundry. Environmental Chemistry. 2020; 17 (5):355.
Chicago/Turabian StyleSilvia Pugliese; Malte Frydenlund Jespersen; Jakob Boyd Pernov; Justin Shenolikar; Jesper Nygaard; Ole John Nielsen; Matthew S. Johnson. 2020. "Chemical analysis and origin of the smell of line-dried laundry." Environmental Chemistry 17, no. 5: 355.
Hui Yi; Jingjing Zhang; Hang Xiao; Lei Tong; Qiuliang Cai; Jiamei Lin; Weijia Yu; Matthew Johnson. Compact Algorithms for Predicting of Atmospheric Visibility Using PM2.5, Relative Humidity and NO2. Aerosol and Air Quality Research 2020, 1 .
AMA StyleHui Yi, Jingjing Zhang, Hang Xiao, Lei Tong, Qiuliang Cai, Jiamei Lin, Weijia Yu, Matthew Johnson. Compact Algorithms for Predicting of Atmospheric Visibility Using PM2.5, Relative Humidity and NO2. Aerosol and Air Quality Research. 2020; ():1.
Chicago/Turabian StyleHui Yi; Jingjing Zhang; Hang Xiao; Lei Tong; Qiuliang Cai; Jiamei Lin; Weijia Yu; Matthew Johnson. 2020. "Compact Algorithms for Predicting of Atmospheric Visibility Using PM2.5, Relative Humidity and NO2." Aerosol and Air Quality Research , no. : 1.