A feasibility study of the use of reactive tracers to determine outdoor daytime <scp>OH</scp> radical concentrations within the urban environment

White, Iain R.; Martin, Damien; Petersson, K. F.; Henshaw, S. J.; Nickless, G.; Lloyd‐Jones, Guy C.; Clemitshaw, Kevin C.; Shallcross, Dudley E.

doi:10.1002/asl2.487

Cited by 2 publications

(1 citation statement)

References 36 publications

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“…(iv) Potentially, the most accurate budget‐based approach would involve the intentional release and global observation of a tracer compound that reacts primarily with OH. Such an approach has been proposed at urban or regional scales (Davenport & Singh, ; Prinn, ; White et al, ) but whether such a method could be feasibly scaled to monitor global [OH] over multiyear timescales is not clear. Such an experiment would likely involve very large costs (which would need to be compared to other costly activities such as satellite missions), international cooperation, partnerships with industry (who would need to manufacture large quantities of tracer), and technological advances to develop sensitive detectors.…”

Section: Top‐down Source and Sink Estimation At Global And Regional Smentioning

confidence: 99%

Advancing Scientific Understanding of the Global Methane Budget in Support of the Paris Agreement

Ganesan

Schwietzke²,

Poulter

et al. 2019

Global Biogeochemical Cycles

103

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The 2015 Paris Agreement of the United Nations Framework Convention on Climate Change aims to keep global average temperature increases well below 2 °C of preindustrial levels in the Year 2100. Vital to its success is achieving a decrease in the abundance of atmospheric methane (CH4), the second most important anthropogenic greenhouse gas. If this reduction is to be achieved, individual nations must make and meet reduction goals in their nationally determined contributions, with regular and independently verifiable global stock taking. Targets for the Paris Agreement have been set, and now the capability must follow to determine whether CH4 reductions are actually occurring. At present, however, there are significant limitations in the ability of scientists to quantify CH4 emissions accurately at global and national scales and to diagnose what mechanisms have altered trends in atmospheric mole fractions in the past decades. For example, in 2007, mole fractions suddenly started rising globally after a decade of almost no growth. More than a decade later, scientists are still debating the mechanisms behind this increase. This study reviews the main approaches and limitations in our current capability to diagnose the drivers of changes in atmospheric CH4 and, crucially, proposes ways to improve this capability in the coming decade. Recommendations include the following: (i) improvements to process‐based models of the main sectors of CH4 emissions—proposed developments call for the expansion of tropical wetland flux measurements, bridging remote sensing products for improved measurement of wetland area and dynamics, expanding measurements of fossil fuel emissions at the facility and regional levels, expanding country‐specific data on the composition of waste sent to landfill and the types of wastewater treatment systems implemented, characterizing and representing temporal profiles of crop growing seasons, implementing parameters related to ruminant emissions such as animal feed, and improving the detection of small fires associated with agriculture and deforestation; (ii) improvements to measurements of CH4 mole fraction and its isotopic variations—developments include greater vertical profiling at background sites, expanding networks of dense urban measurements with a greater focus on relatively poor countries, improving the precision of isotopic ratio measurements of 13CH4, CH3D, 14CH4, and clumped isotopes, creating isotopic reference materials for international‐scale development, and expanding spatial and temporal characterization of isotopic source signatures; and (iii) improvements to inverse modeling systems to derive emissions from atmospheric measurements—advances are proposed in the areas of hydroxyl radical quantification, in systematic uncertainty quantification through validation of chemical transport models, in the use of source tracers for estimating sector‐level emissions, and in the development of time and space resolved national inventories. These and other recommendations are proposed for...

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Section: Top‐down Source and Sink Estimation At Global And Regional Smentioning

confidence: 99%

Advancing Scientific Understanding of the Global Methane Budget in Support of the Paris Agreement

Ganesan

Schwietzke²,

Poulter

et al. 2019

Global Biogeochemical Cycles

103

View full text Add to dashboard Cite

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Indoor Exchange Rates and Penetration From Outdoors in an Instrumented Terraced House (Townhouse) Using Gas Tracers: Implications for Particles and Gases Indoors

Matthews,

Khan,

Wright

et al. 2024

Indoor Air

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Air exchange rate is a key determinant of indoor air quality which is highly variable within the rooms of a naturally ventilated terraced house (townhouse). Window opening can increase the air exchange rate, but internal door opening between rooms inside decreases the rate. Inert perfluorocarbon gas‐phase tracers demonstrated flow within the house, and the penetration of tracers released outside into the house showed a strong dependence on wind speed and wind direction. Between experiments, it was found that the tracer could be detected within certain parts of the house weeks after the initial release, with implications for pollutants and their impact on the indoor environment. A limited number of reactive tracer experiments suggested an upper limit for indoor [OH]~1 × 105 molecule cm-3 with up to 0.5 ppt of [NO3] estimated, leading to an estimated indoor lifetime for d5 isoprene of many hours. Ultrafine particulate matter generated in the kitchen travels throughout the house, and the persistence of elevated aerosol concentrations is seen even in well‐ventilated rooms, with implications for particle exposure in the evening and during the night.

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A feasibility study of the use of reactive tracers to determine outdoor daytime OH radical concentrations within the urban environment

Cited by 2 publications

References 36 publications

Advancing Scientific Understanding of the Global Methane Budget in Support of the Paris Agreement

Advancing Scientific Understanding of the Global Methane Budget in Support of the Paris Agreement

Indoor Exchange Rates and Penetration From Outdoors in an Instrumented Terraced House (Townhouse) Using Gas Tracers: Implications for Particles and Gases Indoors

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