Publications by authors named "C H Halios"

Article Synopsis
  • Urbanization and climate change are exacerbating extreme heat events in cities, but urban green-blue-grey infrastructure (GBGI) like parks and wetlands can help cool summer temperatures.
  • A systematic review analyzed 202 studies on 51 types of GBGI, highlighting that while some (like green walls and street trees) are well-researched for cooling effects, others (like zoological gardens and private gardens) have been largely overlooked.
  • Future climate shifts may reduce the effectiveness of current GBGI, so it's important to consider multiple benefits and enhance planning for these infrastructures to maximize their cooling potential.
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One of the more important classes of potentially toxic indoor air chemicals are the Volatile Organic Compounds (VOCs). However, due to a limited understanding of the relationships between indoor concentrations of individual VOCs and health outcomes, there are currently no universal health-based guideline values for VOCs within Europe including the UK. In this study, a systematic search was conducted designed to capture evidence on concentrations, emissions from indoor sources, and health effects for VOCs measured in European residences.

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The study of the boundary layer can be most difficult when it is in transition and forced by a complex surface, such as an urban area. Here, a novel combination of ground-based remote sensing and in situ instrumentation in central London, UK, is deployed, aiming to capture the full evolution of the urban boundary layer (UBL) from night-time until the fully-developed convective phase. In contrast with the night-time stable boundary layer observed over rural areas, the night-time UBL is weakly convective.

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Nine methods to determine local-scale aerodynamic roughness length and zero-plane displacement are compared at three sites (within 60 m of each other) in London, UK. Methods include three anemometric (single-level high frequency observations), six morphometric (surface geometry) and one reference-based approach (look-up tables). A footprint model is used with the morphometric methods in an iterative procedure.

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Measurement of air exchange rate provides critical information in energy and indoor-air quality studies. Continuous measurement of ventilation rates is a rather costly exercise and requires specific instrumentation. In this work, an alternative methodology is proposed and tested, where the air exchange rate is calculated by utilizing indoor and outdoor routine measurements of a common pollutant such as SO2, whereas the uncertainties induced in the calculations are analytically determined.

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