Indoor air quality : Causes, controls and consequences

Farr, Charlotte and Whyatt, Duncan and Sweetman, Andrew and Booker, Douglas (2021) Indoor air quality : Causes, controls and consequences. PhD thesis, Lancaster University.

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Abstract

This thesis aimed to understand the causes, controls and consequences of managing indoor air quality with an emphasis on ventilation throughout, and considerations to energy efficiency. This was achieved through three complimentary sets of experiments. First this thesis analysed particle number concentrations associated with a series of discrete cooking events to evaluate the efficacy of different types of ventilation in “real world” domestic settings. We identified and characterised 128 discrete cooking events and observed large increases (up to 106 particles/cm3) in particle number concentration in response to these events. A series of key metrics were adopted to enable comparisons to be made between different source and ventilation combinations which revealed that natural ventilation was the most effective means of reducing particle number concentrations in terms of time to background. Second, we replicated these discrete cooking experiments in a specialist test facility to quantify the energy penalties associated with attempts to improve indoor air quality through use of ventilation. We found that energy penalties are modest (0.082–0.193 kWh) if a period of window opening was restricted to no more than 20 minutes, and that the indoor air quality benefits from this are significant in terms of particle removal. We found that the energy penalties associated with mechanical extract ventilation were even lower for such a period (0.063kWh), and that mechanical ventilation provides the best means of meeting the dual objectives of good indoor air quality and energy efficiency. Third, we investigated the prevalence of volatile organic compounds within buildings across a university campus to assess the association between volatile organic compounds concentrations and sustainable building standards. We concluded that there were no associations between sustainable building standard ratings and volatile organic compound concentrations, which could result from a lack of indoor air quality related incentives. We suggest a framework for future sustainable building assessment that not only considers ventilation for improving building sustainability and indoor air quality, but also combines continuous total volatile organic compound measurements with detailed speciation. This thesis was supported by NAQTS who provided access to portable, state-of-the-art V2000 air quality monitoring units. We reflect on the value of such instrumentation and the role it may play in raising public awareness of indoor air quality issues in public and private settings.