Investigating the background and local contribution of the oxidants in London and Bangkok

Khan, M. Anwar H.; Holland, Rayne; Foulds, Amy; Matthews, James; Panditharatne, Sanjeevani; Jenkin, Michael E.; Lowe, Douglas; Navasumrit, Panida; Percival, Carl J.; Shallcross, Dudley E.

doi:10.1039/d0fd00086h

Cited by 4 publications

(4 citation statements)

References 59 publications

(51 reference statements)

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“…Previously, fleet technology improvement, such as the introduction of the 1992 catalytic convertors legislation, requiring all petrol vehicles to be fitted with catalytic convertors, which likely also led to 'cleaner' emissions [8]. Decreasing trends of other pollutants found in vehicle emissions, such as NO x , are consistent with this data, supporting the influence of advanced technology [46]. Furthermore, multiple emission control strategies were introduced in line with the London Mayor's Air Quality Strategy in 2010, including the implementation of the London Low Emission Zone (LEZ), congestion charging, and diesel-electric hybrid buses [47,48].…”

Section: Resultssupporting

confidence: 69%

Investigating the Variation of Benzene and 1,3-Butadiene in the UK during 2000–2020

Holland

Khan²,

Matthews³

et al. 2022

IJERPH

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The concentrations of benzene and 1,3-butadiene in urban, suburban, and rural sites of the U.K. were investigated across 20 years (2000–2020) to assess the impacts of pollution control strategies. Given the known toxicity of these pollutants, it is necessary to investigate national long-term trends across a range of site types. We conclude that whilst legislative intervention has been successful in reducing benzene and 1,3-butadiene pollution from vehicular sources, previously overlooked sources must now be considered as they begin to dominate in contribution to ambient pollution. Benzene concentrations in urban areas were found to be ~5-fold greater than those in rural areas, whilst 1,3-butadiene concentrations were up to ~10-fold greater. The seasonal variation of pollutant concentration exhibited a maximum in the winter and a minimum in the summer with summer: winter ratios of 1:2.5 and 1:1.6 for benzene and 1,3-butadiene, respectively. Across the period investigated (2000–2020), the concentrations of benzene decreased by 85% and 1,3-butadiene concentrations by 91%. A notable difference could be seen between the two decades studied (2000–2010, 2010–2020) with a significantly greater drop evident in the first decade than in the second, proving, whilst previously successful, legislative interventions are no longer sufficiently limiting ambient concentrations of these pollutants. The health impacts of these pollutants are discussed, and cancer impact indices were utilized allowing estimation of cancer impacts across the past 20 years for different site types. Those particularly vulnerable to the adverse health effects of benzene and 1,3-butadiene pollution are discussed.

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Section: Resultssupporting

confidence: 69%

Investigating the Variation of Benzene and 1,3-Butadiene in the UK during 2000–2020

Holland

Khan²,

Matthews³

et al. 2022

IJERPH

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“…The strong reduction of anthropogenic emissions during the COVID19 lockdowns showed that only highly urbanized areas experienced an increase in O 3 concentration associated with a decrease in NOx concentration of up to 30%, while oxidant levels remained stable (e.g., Deroubaix et al, 2021;Gaubert et al, 2021). Misrepresentation of anthropogenic emissions in air quality models can lead to a bias in modeled oxidant level in megacities (e.g., Khan et al, 2021). However, the observed increases in O 3 concentrations during the COVID19 pandemic in São Paulo and even in Rio de Janeiro (e.g., Beringui et al, 2022;Nakada & Urban, 2020), are not reproduced by the global simulations performed by Gaubert et al (2021).…”

Section: Introductionmentioning

confidence: 99%

Intercomparison of Air Quality Models in a Megacity: Toward an Operational Ensemble Forecasting System for São Paulo

Deroubaix,

Hoelzemann,

Ynoue

et al. 2024

JGR Atmospheres

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An intercomparison of four regional air quality models is performed in the tropical megacity of São Paulo with the perspective of developing a forecasting system based on a model ensemble. Modeled concentrations of the main regulated pollutants are compared with combined observations in the megacity center, after analyzing the spatial scale of representativeness of air monitoring stations. During three contrasting periods characterized by different types of pollution events, the hourly concentrations of carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), and particulate matter (PM2.5 and PM10) modeled by the ensemble are in moderate agreement with observations. The median of the ensemble provides the best performance (R ≈ 0.7 for CO, 0.7 for NOx, 0.5 for SO2, 0.5 for PM2.5, and 0.4 for PM10) because each model has periods and pollutants for which it has the best agreement. NOx concentration is modeled with a large inter‐model variability, highlighting potential for improvement of anthropogenic emissions. Pollutants transported by biomass burning events strongly affect the air quality in São Paulo and are associated with significant inter‐model variability. Modeled hourly concentration of ozone (O3) is overestimated during the day (≈20 ppb) and underestimated at night (≈10 ppb), while nitrogen dioxide (NO2) is overestimated at night (≈20 ppb). The observed O3 concentration is best reproduced by the median of the ensemble (R ≈ 0.8), taking advantage of the variable performance of the models. Therefore, an operational air quality forecast system based on a regional model ensemble is promising for São Paulo.

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“…As such, VOCs are classified as air pollutants and some legislative interventions have been introduced in an attempt to limit their ambient concentrations 11 . However, the adverse effects extend beyond their direct effects 12 . The formation of secondary pollutants, such as ozone and particulate matters, have significant health, climate, and air quality impacts 13–19 .…”

Section: Introductionmentioning

confidence: 99%

“…11 However, the adverse effects extend beyond their direct effects. 12 The formation of secondary pollutants, such as ozone and particulate matters, have significant health, climate, and air quality impacts. [13][14][15][16][17][18][19] Whilst VOC air quality objectives (AQOs) are generally met across the UK (though explicit AQOs for VOCs are admittedly scarce 11 ), ambient ozone levels continue to exceed long-term AQOs.…”

Section: Introductionmentioning

confidence: 99%

Gas‐phase kinetics, POCPs, and an investigation of the contributions of VOCs to urban ozone production in the UK

Holland

Khan

Derwent³

et al. 2023

Int J of Chemical Kinetics

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Ambient concentrations of 22 volatile organic compounds (VOCs) measured at London Marylebone Road (LMR), an urban traffic site, and London Eltham (LE), an urban background site, were analyzed over a period of 23 years to assess the impact of pollution control strategies. A significant decrease in ambient concentration is seen for the majority of VOCs analyzed with total VOC burden decreasing by 76% and 59% for LMR and LE, respectively, across the period studied. This is likely as a result of legislative controls. This analysis was extended to consider the dominant contribution of VOCs to ozone formation at the sites utilizing photochemical ozone creation potential (POCP) values.Similarly, the overall reactivity of the VOC burden at the sites has resulted in a significant decrease of 11% and 7% per year in ozone formation potential (OFP) for LMR and LE, respectively. At LMR, the declines in OFP for VOCs associated with road traffic emissions are all in good agreement at 11%-13% decrease per year. Reasonable agreement is also seen at LE with a decrease of 6%-11% per year in OFP of the VOCs related to traffic sources. VOCs related to non-traffic sources, namely ethane and propane from natural gas leakage, did not see a significant decline over the study period at either site. The variation and composition of the overall VOC burden was compared across three decadal time periods (1997-2000, 2001-2010, 2011-2019) and saw an increase in significance of these pollutants at both sites. At LMR, ethane and propane moved from the fifth and eleventh largest contributors to total VOC burden in 1997-2000 to the first and second largest contributors in 2011-2019. At LE, a similar trend is seen with ethane and propane becoming the first and second largest contributors in the most recent time period, up from second and eighth at the beginning of the dataset. The similarity between these sites suggests such pollutants are not sufficiently controlled under current legislation. The increase in significance of ethane and propane was mirrored in their contribution to ozone generation potential at both sites but ethene continues to dominate in contribution to OFP. At LMR, etheneThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Investigating the background and local contribution of the oxidants in London and Bangkok

Abstract: The contribution of NOx emissions and background O3 to the sources and partitioning of the oxidants [OX(=O3+NO2)] at the Marylebone Road site in London during the 2000s and 2010s has...

Cited by 4 publications

References 59 publications

Investigating the Variation of Benzene and 1,3-Butadiene in the UK during 2000–2020

Investigating the Variation of Benzene and 1,3-Butadiene in the UK during 2000–2020

Intercomparison of Air Quality Models in a Megacity: Toward an Operational Ensemble Forecasting System for São Paulo

Gas‐phase kinetics, POCPs, and an investigation of the contributions of VOCs to urban ozone production in the UK

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