Indoor air exposures to VOCs and mould, and relationship with severe asthma

People spend around 90% of their time indoors, either in public or private buildings, which can lead to long-term exposure to poor air quality and be associated with negative health effects, especially in vulnerable people. Two environments of interest were studied during this PhD, dwellings and hospital clinics. In public buildings, the characterisation was focused on volatile organic compounds (VOCs), while in private buildings, VOCs and fungal spores were identified and quantified, both of which have known impacts on respiratory health. There is little research on VOC exposures, especially in clinical environments, while research on fungal exposures in the home was mainly focused on damp and visible mould with less information on fungal species.

Indoor air pollution was characterised in private (32 dwellings, including the home of 14 people with patients) and public (2 hospitals) buildings. The potential impact on the health of the buildings’ occupants was examined. Beforehand, protocols were developed and tested to quantify and identify VOCs and fungal spores.

In the dwellings, 38 VOCs were quantified and their sum (TVOC) ranged from 205 to 933 μgm-3. The most abundant VOCs were from aliphatic hydrocarbon and alcohol groups. The most commonly detected fungal species was Cladosporium herbarum, followed by Aspergillus fumigatus. VOC concentrations had an impact on peak flow readings and the use of medication for two people with asthma, while no associations were seen for fungal spores. The hospital VOCs analysis was the first for UK hospitals and the largest worldwide. The four VOCs with the highest concentrations were most likely released by healthcare activities (e.g.2-propanol, ethyl chloride and acetone) or related to the ingress of vehicle emissions (e.g. hexane). Hazard Quotient (HQ) was calculated to identify the potential risk of non-carcinogenic VOCs exposure to the health of healthcare workers. No HQs were measured above 1 which means that no negative health impact would be expected for healthcare workers in the sampled hospitals.

To conclude, the data collected showed how complex indoor pollution can be. In particular in the dwellings which all had unique ‘fingerprints’ of VOC and fungal concentrations.