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Title: An assessment of indoor air quality at two contrasting location and building ventilation types in London
Author: Mohd Aris, Mohd Shukri
Awarding Body: King's College London (University of London)
Current Institution: King's College London (University of London)
Date of Award: 2013
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Background: People spend most of their time indoors, in buildings such as schools and offices, as well as their homes. Recent interest in Indoor Air Quality (IAQ) suggests that the contribution of outdoor pollutants and indoor airborne particulate and gaseous pollutants may be responsible for the aggregation of a number of respiratory illnesses. Because of these possible health implications, it is important to understand the characteristics of each air pollutant inside/outside (I/O) the building and the variables affecting the degree of exposure to them. Objectives: This was achieved by long-term monitoring of a range of pollutants at two contrasting building types and locations within London. The transfer of pollutants(NOX, NO2, O3 and PMs) and particulate toxicity (PMTSP) within I/O sources over a wide range of meteorological condition, occupancy and seasonality was then characterised. Results 1 (Case 1): At naturally ventilated school building (urban background), paired long term monitoring revealed that the indoor gaseous pollutant concentration reacted differently according to occupancy and seasonality. Due to the fact that indoor NO concentration in the classroom was possibly dominated by indoor source, its presence was also believed to play an important role of reducing O3 in the classroom which mainly came attributed from outdoors during summer time. The increment of indoor larger (PM10) and coarse particle (PM2.5 – 10) was attributed when the building was actively used and identified to be linked from the certain type of classroom activity. However, a greater proportion of indoor PM2.5 was contributed from outdoors. Results 2 (Case 2): In contrast, a different pattern of diurnal variation profiles was observed in the mechanically ventilated office building (roadside site). An extreme indoor concentration of indoor NOX and NO2 monitored during rush hour on working-days were explained by the outdoor penetration. An extension study (building improvement) showed a clear reduction pattern in PM concentration; however it did not solve the high NO2 problem. Results 3: The novel time series of oxidative potential (OP) dataset established in this study highlightedaclear difference between the two sites. Indoor OP metrics in the roadside building recorded higher depletion rates compared to the urban background site. At urban background site, when indoor OP dataset were categorised and group as building occupancy and seasonal dependent, the indoor PM OP antioxidants metrics was found to have a higher depletion rate during occupied period and was observed during winter time, which particularly in particulate mass metric. At roadside site, interestingly, a significant decrease in PM-induced antioxidant depletion indoors, observed after the door upgrade. This study demonstrated that PM OP analysis from both internal and external sources is a useful tool for illustrating any changes in sources in the transfer of pollutants into a building. Conclusion: These monitoring results reveal the complexity of internal-external air quality relationship within building envelopes referring to ventilation type and location specificity. The ingress of outdoor pollution contribution in poor IAQ were also driven by other factors such as urban building orientation, the wide range of building occupancy and different set of ventilation types.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available