Matching Items (3)
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- All Subjects: Particulate matter
- All Subjects: Litter
- Creators: Hamilton, Kerry
- Creators: Cohn, S.
Description
The occurrence of micro-and nanoplastic (MNP) debris in the environment is a research area of considerable public health concern. Various combinations of methods for extraction, isolation, and quantification of MNP have been applied but literature studies evaluating the appropriateness and efficacy of these protocols are lacking. A meta-analysis of the literature (n=134; years 2010-2017) was conducted to inventory and assess the appropriateness of methodologies employed. Some 30.6% of studies employed visual identification only, which carried a calculated misidentification error of 25.8-74.2%. An additional 6.7% of studies reported counts for particles smaller than the cutoff value of the selected collection pore size, and 9.7% of studies utilized extraction solution densities which exclude some of the polymers commonly occurring in the environments investigated. A composite value of data vulnerability of 43.3% was determined for the sample, indicating considerable weaknesses in the robustness of information available on MNP occurrence and type. Additionally, the oxidizing solutions documented in the literature frequently were deemed unsuccessful in removing interfering organic matter. Whereas nanoplastics measuring <1 µm in diameter are likely principal drivers of health risk, polymer fragments reported on in the literature are much larger, measuring 10+ µm in diameter due to lack of standardized methods. Thus, current inventories of MNP in the environmental MNP feature data quality concerns that should be addressed moving forward by using more robust and standardized techniques for sampling, processing and polymer identification to improve data quality and avoid the risk of misclassification.
ContributorsCook, Cayla R (Author) / Halden, Rolf U. (Thesis advisor) / Hamilton, Kerry (Committee member) / Mascaro, Giuseppe (Committee member) / Arizona State University (Publisher)
Created2018
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
Description
-Please adjust the format of the abstract. m-3 should be typed as "m to the minus 3" with the "minus 3" in superscript
-see the additional "abstract.pdf" document for formatting
In arid environments like Phoenix, many professional and residential outdoor spaces are cooled by the use of misting systems. These systems spray a fine mist of water droplets that cool down the surrounding air through the endothermic evaporation process. When the water droplets evaporate, they leave behind dissolved material that is present in the water, generating ambient particulate matter (PM). Thus, misting systems are a point source of PM. Currently there is no information on their impact on air quality in close proximity to these systems, or on the chemical composition of the particulate matter generated by the evaporating mist.
In this project, PM concentrations are found to increase on average by a factor of 8 from ambient levels in the vicinity of a residential misting system in controlled experiments. PM concentrations in public places that use misting systems are also investigated. The PM10 concentrations in public places ranged from 0.102 ± 0.010 mg m-3 to 1.47 ± 0.15 mg m-3, and PM2.5 ranged from 0.095 ± 0.010 mg m-3 to 0.99 ± 0.10 mg m-3. Air quality index (AQI) values based on these concentrations indicate that these levels of PM range from unhealthy to hazardous in most cases. PM concentrations tend to decrease after remaining relatively constant with increasing distance from misting systems. Chemical data reveal that chloride and magnesium ions may be used as tracers of aerosolized water from misting systems. The average chloride concentration was 71 µg m-3 in misting samples and below the detection limit for Cl- (< 8.2 µg m-3) in ambient samples. The average magnesium concentration was 11.7 µg m-3 in misting samples and 0.23 µg m-3 in ambient samples.
-see the additional "abstract.pdf" document for formatting
In arid environments like Phoenix, many professional and residential outdoor spaces are cooled by the use of misting systems. These systems spray a fine mist of water droplets that cool down the surrounding air through the endothermic evaporation process. When the water droplets evaporate, they leave behind dissolved material that is present in the water, generating ambient particulate matter (PM). Thus, misting systems are a point source of PM. Currently there is no information on their impact on air quality in close proximity to these systems, or on the chemical composition of the particulate matter generated by the evaporating mist.
In this project, PM concentrations are found to increase on average by a factor of 8 from ambient levels in the vicinity of a residential misting system in controlled experiments. PM concentrations in public places that use misting systems are also investigated. The PM10 concentrations in public places ranged from 0.102 ± 0.010 mg m-3 to 1.47 ± 0.15 mg m-3, and PM2.5 ranged from 0.095 ± 0.010 mg m-3 to 0.99 ± 0.10 mg m-3. Air quality index (AQI) values based on these concentrations indicate that these levels of PM range from unhealthy to hazardous in most cases. PM concentrations tend to decrease after remaining relatively constant with increasing distance from misting systems. Chemical data reveal that chloride and magnesium ions may be used as tracers of aerosolized water from misting systems. The average chloride concentration was 71 µg m-3 in misting samples and below the detection limit for Cl- (< 8.2 µg m-3) in ambient samples. The average magnesium concentration was 11.7 µg m-3 in misting samples and 0.23 µg m-3 in ambient samples.
ContributorsKnight, William Louis (Co-author) / Knight, William (Co-author) / Herckes, Pierre (Thesis director) / Fraser, Matthew (Committee member) / Hamilton, Kerry (Committee member) / School of Sustainability (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05