Publications by authors named "Christine F Braban"

Under the EU Air Quality Directive (AQD) 2008/50/EC member states are required to undertake routine monitoring of PM composition at background stations. The AQD states for PM speciation this should include at least: nitrate , sulfate , chloride (Cl), ammonium (NH4), sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), elemental carbon (EC) and organic carbon (OC). Until 2017, it was the responsibility of each country to determine the methodology used to report the composition for the inorganic components of PM.

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Article Synopsis
  • Anthropogenic activities release around 2,000 metric tons of mercury annually, affecting remote ecosystems and leading to inconsistencies in reported emissions and atmospheric concentrations in the Northern Hemisphere.
  • Despite reported increases in mercury emissions over the past 30 years, data analysis shows a declining trend in atmospheric mercury levels, indicating that actual emissions must have decreased significantly, contradicting existing inventories.
  • By using statistical modeling of data from 51 monitoring stations, the study highlights a decline in mercury concentrations from 2005 to 2020, suggesting that reductions in local emissions, rather than reemissions of legacy mercury, are primarily responsible for these trends and raising questions about the reliability of current emission inventories.
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Asthma, characterized by airway inflammation, sensitization and constriction, and leading to symptoms including cough and dyspnoea, affects millions of people globally. Air pollution is a known asthma trigger, yet how it is experienced is understudied and how individuals with asthma interact with air quality information and manage exacerbation risks is unclear. This study aimed to explore how people living with asthma in Scotland, UK, experienced and managed their asthma in relation to air pollution.

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Article Synopsis
  • PM (fine particulate matter) is linked to acute asthma attacks and long-term respiratory issues, with exposure varying significantly according to different environments.
  • Low-cost sensors were used by 28 non-smoking asthma patients in Scotland to track their PM exposure over a week, coinciding with their activities and health notes.
  • The study found that higher PM exposure correlated with increased asthma symptoms but did not impact the use of rescue inhalers, highlighting gaps in current air quality monitoring that need to be addressed for better health insight.
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This review is a summary of the most up-to-date knowledge regarding assessment of atmospheric deposition of reactive nitrogen ( ) pollutants across complex terrain in the UK. Progress in the understanding of the mechanisms and quantification of deposition in areas of complex topography is slow, as no concerted attempts to measure the components of in complex terrain have been made in the last decade. This is likely due to the inherent complexity of the atmospheric processes and chemical interactions which contribute to deposition in these areas.

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Exposure to air pollution prematurely kills 7 million people globally every year. Policy measures designed to reduce emissions of pollutants, improve ambient air and consequently reduce health impacts, can be effective, but are generally slow to generate change. Individual actions can therefore supplement policy measures and more immediately reduce people's exposure to air pollution.

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Ammonia and ammonium have received less attention than other forms of air pollution, with limited progress in controlling emissions at UK, European and global scales. By contrast, these compounds have been of significant past interest to science and society, the recollection of which can inform future strategies. Sal ammoniac (, ) is found to have been extremely valuable in long-distance trade ( AD 600-1150) from Egypt and China, where 6-8 kg N could purchase a human life, while air pollution associated with collection was attributed to this nitrogen form.

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Human health burdens associated with long-term exposure to particulate matter (PM) are substantial. The metrics currently recommended by the World Health Organization for quantification of long-term health-relevant PM are the annual average PM10 and PM2.5 mass concentrations, with no low concentration threshold.

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Anaerobic digestion (AD) is becoming increasingly implemented within organic waste treatment operations. The storage and processing of large volumes of organic wastes through AD has been identified as a significant source of ammonia (NH3) emissions, however the totality of ammonia emissions from an AD plant have not been previously quantified. The emissions from an AD plant processing food waste were estimated through integrating ambient NH3 concentration measurements, atmospheric dispersion modelling, and comparison with published emission factors (EFs).

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Adverse health effects from exposure to air pollution are a global challenge and of widespread concern. Recent high ambient concentration episodes of air pollutants in European cities highlighted the dynamic nature of human exposure and the gaps in data and knowledge about exposure patterns. In order to support health impact assessment it is essential to develop a better understanding of individual exposure pathways in people's everyday lives by taking account of all environments in which people spend time.

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Existing descriptions of bi-directional ammonia (NH3) land-atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate-dependence of emissions.

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We examined the consequences of the spatial heterogeneity of atmospheric ammonia (NH₃) by measuring and modelling NH₃ concentrations and deposition at 25 m grid resolution for a rural landscape containing intensive poultry farming, agricultural grassland, woodland and moorland. The emission pattern gave rise to a high spatial variability of modelled mean annual NH₃ concentrations and dry deposition. Largest impacts were predicted for woodland patches located within the agricultural area, while larger moorland areas were at low risk, due to atmospheric dispersion, prevailing wind direction and low NH3 background.

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Hydrogen peroxide (H(2)O(2)) is an important atmospheric oxidant that can serve as a sensitive indicator for HO(x) (OH + HO(2)) chemistry. We report the first direct experimental determination of the uptake coefficient for the heterogeneous reaction of gas-phase hydrogen peroxide (H(2)O(2)) with titanium dioxide (TiO(2)), an important component of atmospheric mineral dust aerosol particles. The kinetics of H(2)O(2) uptake on TiO(2) surfaces were investigated using an entrained aerosol flow tube (AFT) coupled with a chemical ionization mass spectrometer (CIMS).

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