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- All Subjects: Particulate matter
- All Subjects: Photovoltaic power systems--Environmental aspects.
- Creators: Fraser, Matthew P
- Creators: Cohn, S.
- Creators: Fraser, M.P.
Description
Americans spend upwards of 90% of their time indoors, hence indoor air quality (IAQ) and the impact of IAQ on human health is a major public health concern. IAQ can be negatively impacted by outdoor pollution infiltrating indoors, the emission of indoor pollutants, indoor atmospheric chemistry and poor ventilation. Energy saving measures like retrofits to seal the building envelope to prevent the leakage of heated or cooled air will impact IAQ. However, existing studies have been inconclusive as to whether increased energy efficiency is leading to detrimental IAQ. In this work, field campaigns were conducted in apartment homes in Phoenix, Arizona to evaluate IAQ as it relates to particulate matter (PM), carbonyls, and tobacco specific nitrosamines (TSNA).
To investigate the impacts of an energy efficiency retrofit on IAQ, indoor and outdoor air quality sampling was carried out at Sunnyslope Manor, a city-subsidized senior living apartment complex. Measured indoor formaldehyde levels before the building retrofit exceeded reference exposure limits, but in the long term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long term follow-up sampling within certain resident subpopulations (i.e. residents who reported smoking and residents who had lived longer at the apartment complex). Additionally, indoor glyoxal and methylglyoxal exceeded outdoor concentrations, with methylglyoxal being more prevalent pre-retrofit than glyoxal, suggesting different chemical pathways are involved. Indoor concentrations reported are larger than previous studies. TSNAs, specifically N'-nitrosonornicotine (NNN), 4-(methyl-nitrosamino)-4-(3-pyridyl)-butanal (NNA) and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK) were evaluated post-retrofit at Sunnyslope Manor. Of the units tested, 86% of the smoking units and 46% of the non-smoking units had traces of at least one of the nitrosamines.
To investigate the impacts of an energy efficiency retrofit on IAQ, indoor and outdoor air quality sampling was carried out at Sunnyslope Manor, a city-subsidized senior living apartment complex. Measured indoor formaldehyde levels before the building retrofit exceeded reference exposure limits, but in the long term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long term follow-up sampling within certain resident subpopulations (i.e. residents who reported smoking and residents who had lived longer at the apartment complex). Additionally, indoor glyoxal and methylglyoxal exceeded outdoor concentrations, with methylglyoxal being more prevalent pre-retrofit than glyoxal, suggesting different chemical pathways are involved. Indoor concentrations reported are larger than previous studies. TSNAs, specifically N'-nitrosonornicotine (NNN), 4-(methyl-nitrosamino)-4-(3-pyridyl)-butanal (NNA) and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK) were evaluated post-retrofit at Sunnyslope Manor. Of the units tested, 86% of the smoking units and 46% of the non-smoking units had traces of at least one of the nitrosamines.
ContributorsFrey, Sarah E (Author) / Herckes, Pierre (Thesis advisor) / Fraser, Matthew P (Thesis advisor) / Destaillats, Hugo (Committee member) / Chizmeshya, Andrew (Committee member) / Arizona State University (Publisher)
Created2014
Description
Photovoltaics (PV) is an environmentally promising technology to meet climate goals and transition away from greenhouse-gas (GHG) intensive sources of electricity. The dominant approach to improve the environmental gains from PV is increasing the module efficiency and, thereby, the renewable electricity generated during use. While increasing the use-phase environmental benefits, this approach doesn’t address environmentally intensive PV manufacturing and recycling processes.
Lifecycle assessment (LCA), the preferred framework to identify and address environmental hotspots in PV manufacturing and recycling, doesn’t account for time-sensitive climate impact of PV manufacturing GHG emissions and underestimates the climate benefit of manufacturing improvements. Furthermore, LCA is inherently retrospective by relying on inventory data collected from commercial-scale processes that have matured over time and this approach cannot evaluate environmentally promising pilot-scale alternatives based on lab-scale data. Also, prospective-LCAs that rely on hotspot analysis to guide future environmental improvements, (1) don’t account for stake-holder inputs to guide environmental choices in a specific decision context, and (2) may fail in a comparative context where the mutual differences in the environmental impacts of the alternatives and not the environmental hotspots of a particular alternative determine the environmentally preferable alternative
This thesis addresses the aforementioned problematic aspects by (1)using the time-sensitive radiative-forcing metric to identify PV manufacturing improvements with the highest climate benefit, (2)identifying the environmental hotspots in the incumbent CdTe-PV recycling process, and (3)applying the anticipatory-LCA framework to identify the most environmentally favorable alternative to address the recycling hotspot and significant stakeholder inputs that can impact the choice of the preferred recycling alternative.
The results show that using low-carbon electricity is the most significant PV manufacturing improvement and is equivalent to increasing the mono-Si and multi-Si module efficiency from a baseline of 17% to 21.7% and 16% to 18.7%, respectively. The elimination of the ethylene-vinyl acetate encapsulant through mechanical and chemical processes is the most significant environmental hotspot for CdTe PV recycling. Thermal delamination is the most promising environmental alternative to address this hotspot. The most significant stake-holder input to influence the choice of the environmentally preferable recycling alternative is the weight assigned to the different environmental impact categories.
Lifecycle assessment (LCA), the preferred framework to identify and address environmental hotspots in PV manufacturing and recycling, doesn’t account for time-sensitive climate impact of PV manufacturing GHG emissions and underestimates the climate benefit of manufacturing improvements. Furthermore, LCA is inherently retrospective by relying on inventory data collected from commercial-scale processes that have matured over time and this approach cannot evaluate environmentally promising pilot-scale alternatives based on lab-scale data. Also, prospective-LCAs that rely on hotspot analysis to guide future environmental improvements, (1) don’t account for stake-holder inputs to guide environmental choices in a specific decision context, and (2) may fail in a comparative context where the mutual differences in the environmental impacts of the alternatives and not the environmental hotspots of a particular alternative determine the environmentally preferable alternative
This thesis addresses the aforementioned problematic aspects by (1)using the time-sensitive radiative-forcing metric to identify PV manufacturing improvements with the highest climate benefit, (2)identifying the environmental hotspots in the incumbent CdTe-PV recycling process, and (3)applying the anticipatory-LCA framework to identify the most environmentally favorable alternative to address the recycling hotspot and significant stakeholder inputs that can impact the choice of the preferred recycling alternative.
The results show that using low-carbon electricity is the most significant PV manufacturing improvement and is equivalent to increasing the mono-Si and multi-Si module efficiency from a baseline of 17% to 21.7% and 16% to 18.7%, respectively. The elimination of the ethylene-vinyl acetate encapsulant through mechanical and chemical processes is the most significant environmental hotspot for CdTe PV recycling. Thermal delamination is the most promising environmental alternative to address this hotspot. The most significant stake-holder input to influence the choice of the environmentally preferable recycling alternative is the weight assigned to the different environmental impact categories.
ContributorsTriplican Ravikumar, Dwarakanath (Author) / Seager, Thomas P (Thesis advisor) / Fraser, Matthew P (Thesis advisor) / Chester, Mikhail (Committee member) / Sinha, Parikhit (Committee member) / Tao, Meng (Committee member) / Arizona State University (Publisher)
Created2016
Description
To investigate the impacts of an energy efficiency retrofit, indoor air quality and resident health were evaluated at a low‐income senior housing apartment complex in Phoenix, Arizona, before and after a green energy building renovation. Indoor and outdoor air quality sampling was carried out simultaneously with a questionnaire to characterize personal habits and general health of residents. Measured indoor formaldehyde levels before the building retrofit routinely exceeded reference exposure limits, but in the long‐term follow‐up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long‐term follow‐up sampling within certain resident subpopulations (i.e. residents who report smoking and residents who had lived longer at the apartment complex).
ContributorsFrey, S.E. (Author) / Destaillats, H. (Author) / Cohn, S. (Author) / Ahrentzen, S. (Author) / Fraser, M.P. (Author)
Created2015