Early history and rationale for outdoor chamber work at the University of North Carolina

Jeffries, Harvey E.; Kamens, Richard M.; Sexton, Kenneth G.

doi:10.1071/en13901

Cited by 6 publications

(4 citation statements)

References 69 publications

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“…Outdoor chambers use natural solar irradiation but there can be high levels of uncertainty introduced due to difficulties in the measurement of the natural solar flux and its response to solar zenith angle, haze, clouds, plastic exterior coverings, etc. Pitts 1986, 2000;Jeffries, Fox, and Kamens 1976;Jeffries, Kamens, and Sexton 2013). Dodge (2000) provides a comprehensive guide to environmental chambers and they are used in comparing chemical mechanisms.…”

Section: Methods Initially Used For the Development Of Gas-phase Chemical Mechanisms For Air Qualitymentioning

confidence: 99%

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A perspective on the development of gas-phase chemical mechanisms for Eulerian air quality models

Stockwell

Saunders

Goliff

et al. 2019

Journal of the Air & Waste Management Association

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An essential component of a three-dimensional air quality model is its gas-phase mechanism. We present an overview of the necessary atmospheric chemistry and a discussion of the types of mechanisms with some specific examples such as the Master Chemical Mechanism, the Carbon Bond, SAPRC and the Regional Atmospheric Chemistry Mechanism (RACM). The first versions of the Carbon Bond and SAPRC mechanisms were developed through a hierarchy of chemical species approach that relied heavily on chemical environmental chamber data. Now a new approach has been proposed where the first step is to develop a highly detailed explicit mechanism such as the Master Chemical Mechanism and the second step is to test the detailed explicit mechanism against laboratory and field data. Finally, the detailed mechanism is condensed for use in a three-dimensional air quality model. Here it is argued that the development of highly detailed explicit mechanisms is very valuable for research, but we suggest that combining the hierarchy of chemical species and the detailed explicit mechanism approaches would be better than either alone.Implication: Many gas-phase mechanisms are available for urban, regional and global air quality modeling. A "hierarchy of chemical species approach," relying heavily on smog-chamber data was used for the development of the early series of mechanisms. Now the development of large, explicit master mechanisms that may be condensed is a significant, trend. However, a continuing problem with air quality mechanism development is due to the high complexity of atmospheric chemistry and the current availability of laboratory measurements. This problem requires a balance between completeness and speculation so that models maintain their utility for policymakers.

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Section: Methods Initially Used For the Development Of Gas-phase Chemical Mechanisms For Air Qualitymentioning

confidence: 99%

“…It should be noted that chamber wall Note that it has a somewhat similar design to an A-frame house. A history of this chamber is given by Jeffries, Kamens, and Sexton (2013).…”

Section: Methods Initially Used For the Development Of Gas-phase Chemical Mechanisms For Air Qualitymentioning

confidence: 99%

A perspective on the development of gas-phase chemical mechanisms for Eulerian air quality models

Stockwell

Saunders

Goliff

et al. 2019

Journal of the Air & Waste Management Association

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“…Atmospheric simulation chambers provide a compromise between the tightly controlled conditions in laboratory experiments and the real atmosphere, and are also used as excellent testbeds for the development, intercomparison and calibration of instrumentation. The European PHOtoREactor (EUPHORE) in Valencia can be considered a pioneering outdoor chamber facility, which, along with more recent large outdoor chambers (e.g., SAPHIR at Forschungszentrum Jülich) allow for decreasing the surface-to-volume ratios to minimize chamber wall effects, in conjunction with sensitive detection methods, for long duration studies under close-to-ambient concentrations (Rohrer et al, 2005;Jeffries et al, 2013;Li et al, 2021). The huge improvement in the range and sensitivity of chamber instrumentation has led to the ability to comprehensively monitor the chemical evolution of precursor and product species, including radical intermediates such as HO 2 and RO 2 (Fuchs et al, 2008;Onel et al, 2017) and OH reactivity (Fuchs et al, 2017).…”

Section: Atmospheric Simulation Chambersmentioning

confidence: 99%

Opinion: Challenges and needs of tropospheric chemical mechanism development

Ervens,

Rickard,

Aumont

et al. 2024

Preprint

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Abstract. Chemical mechanisms form the core of atmospheric models to describe degradation pathways of pollutants and ultimately inform air quality and climate policy makers and other stakeholders. The accuracy of chemical mechanisms relies on the quality of their input data, which originate from experimental (laboratory, field, chamber) and theoretical (quantum chemistry, theoretical kinetics, machine learning) studies. The development of robust mechanisms requires rigorous and transparent procedures for data collection, mechanism construction and evaluation, and creation of reduced or operationally defined mechanisms. Developments in analytical techniques have led to a large number of identified chemical species in the atmospheric multiphase system which have proved invaluable for our understanding of atmospheric chemistry. At the same time, advances in software and machine learning tools have enabled automated mechanism generation. We discuss strategies for mechanism development, applying empirical or mechanistic approaches. We show the general workflows, how either approach can lead to robust mechanisms and that the two approaches complement each other to result in reliable predictions. Current challenges are discussed related to global change, including shifts in emission scenarios that result in new chemical regimes (e.g. low NO scenarios, wildfires, mega/gigacities) and require the development of new or expanded gas- and aqueous-phase mechanisms. In addition, new mechanisms should be developed to also target oxidation capacity, and aerosol chemistry impacting climate, human and ecosystem health.

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“…Exploration of in situ biogenic emissions from plants and interactions of plant VOCs with oxidant chemistry [119][120][121]. Other applications have used photochemical reaction products to investigate toxicity to humans [106,122]. Smog chambers have also been used to investigate photochemical pesticide degradation.…”

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confidence: 99%

Atmospheric Chemistry in a Box or a Bag

Hidy¹

2019

Atmosphere

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Environmental chambers have proven to be essential for atmospheric photochemistry research. This historical perspective summarizes chamber research characterizing smog. Experiments with volatile organic compounds (VOCs)-nitrogen oxides (NO x ) have characterized O 3 and aerosol chemistry. These led to the creation and evaluation of complex reaction mechanisms adopted for various applications. Gas-phase photochemistry was initiated and developed using chamber studies. Post-1950s study of photochemical aerosols began using smog chambers. Much of the knowledge about the chemistry of secondary organic aerosols (SOA) derives from chamber studies complemented with specially designed atmospheric studies. Two major findings emerge from post-1990s SOA experiments: (1) photochemical SOAs hypothetically involve hydrocarbons and oxygenates with carbon numbers of 2, and (2) SOA evolves via more than one generation of reactions as condensed material exchanges with the vapor phase during "aging". These elements combine with multiphase chemistry to yield mechanisms for aerosols. Smog chambers, like all simulators, are limited representations of the atmosphere. Translation to the atmosphere is complicated by constraints in reaction times, container interactions, influence of precursor injections, and background species. Interpretation of kinetics requires integration into atmospheric models addressing the combined effects of precursor emissions, surface exchange, hydrometeor interactions, air motion and sunlight.

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Early history and rationale for outdoor chamber work at the University of North Carolina

Cited by 6 publications

References 69 publications

A perspective on the development of gas-phase chemical mechanisms for Eulerian air quality models

A perspective on the development of gas-phase chemical mechanisms for Eulerian air quality models

Opinion: Challenges and needs of tropospheric chemical mechanism development

Atmospheric Chemistry in a Box or a Bag

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