565 research outputs found
Simulating urban soil carbon decomposition using local weather input from a surface model
Non peer reviewe
An assessment of indoor and outdoor air quality in a university environment : a case of University of Limpopo, South Africa
Air pollution of late has been the focus of many studies due to the detrimental health risks
that it poses to individuals. University environments have several academic departments
with peculiar activities that could be affecting the indoor and outdoor air quality (AQ) of
these environments. University settings differ from other environments because of the
variety of activities and different lines of work that go on inside buildings housing academic
departments and their surroundings, which are likely to have an impact on indoor air
quality (IAQ) and outdoor air quality (OAQ) in this environment. Only a few AQ studies
have been done in university sites and surrounds worldwide and in these studies, IAQ
was given primary importance; whereas, the outdoor environment was and is often
neglected. A study comparing both IAQ and OAQ is critical to further understand the
relationship between IAQ and OAQ within a university campus. The University of Limpopo
(UL) in the Mankweng township of South Africa has been undergoing some
refurbishments with numerous construction activities going on in addition to the academic
activities of UL. These activities may be affecting the AQ in this unique environment. The
main aim of this study was to determine differences between indoor and outdoor AQ in a
university environment and to understand how AQ in this unique environment varies with
seasons and building function. The study was carried out in three buildings housing three
different academic departments in UL namely: Department of Physiology and
Environmental Health (PEH), Department of Biochemistry, Microbiology, and
Biotechnology (BMBT) and the Department of Biodiversity (BIOD). Twenty indoor and 20
outdoor measuring sites were identified per departmental building from where real-time
measurements of 11 AQ parameters (linear air velocity (LAV), dry-bulb temperature (Tdb),
relative humidity (RH), carbon monoxide (CO), carbon dioxide (CO2), ozone (O3), sulphur
dioxide (SO2), nitrogen dioxide (NO2), hydrogen sulphide (H2S), non-methane
hydrocarbons (NMHCs) and volatile organic compounds (VOCs)) were taken over three
consecutive days per season. Thus, a total of 60 indoor and 60 outdoor measurements
were taken for each parameter in each of the three buildings of interest per season,
leading to 360 measurements per season and 1440 measurement per parameter over the
one-year period of study across the study area. A hot-wire anemometer was used to
measure LAV, whereas the Q-Trak indoor AQ monitor was used in the measurement of
Tdb, RH, CO and CO2. Aeroqual AQ monitors were employed in the measurement of O3,
SO2, NO2, H2S, NMHCs and VOCs. The Wilcoxon signed ranks test was used to determine differences between indoor and outdoor environments. Significant differences
were found between the indoor and outdoor environments for LAV (all three buildings),
Tdb (PEH and BMBT), RH (BIOD), O3 (all three buildings), NO2 (all three buildings), CO
(all three buildings), CO2 (all three buildings), NMHCs (BMBT and BIOD), and VOCs (all
three buildings) (p < 0.05). Linear air velocity, O3, SO2, CO, CO2, and H2S
values/concentrations across the indoor/outdoor environments were within the
ASHRAE/DEA/WHO guidelines/standards, whereas Tdb, RH and NO2
values/concentrations were not. Air quality in the study area varied with building, with the
best AQ across both the indoor and outdoor environments being within the BIOD building,
whilst the worst AQ across both environments was encountered in the PEH building.
Seasonal differences between buildings were also identified between indoor and outdoor
environments among the PEH, BMBT and BIOD buildings (p < 0.008). Across the indoor
environment, the winter season was found to be the season with the best AQ, since all
the pollutants were found at minimum concentrations. Factors affecting AQ in the study
area included thermal comfort, occupant densities, building function, laboratory
emissions, renovation activities, generators, vehicular emissions, among others. The best
AQ across the outdoor environment occurred during the autumn season, since all the air
pollutants were present at minimal concentrations during this time. The best predictors of
LAV, Tdb, CO, CO2, NO2, and NMHCs were seasons (R2 = 1.000, p < 0.01). For the
parameters RH, H2S, and VOCs, the best predictor was building type (R2 = 1.000, p <
0.01). The indoor and outdoor environment were the best predictors for SO2 (R2 = 0.999,
p < 0.01). Ozone had no single predictor that was found to significantly influence its
concentration in this study. In relation to an air pollution index (API), generally all pollutant
indices fell within the fair, good to very good range when using mean and maxima
concentrations, whereas, corresponding NO2 concentrations throughout the study fell
within the poor to very poor range (105.660–250.000). University management should
take into consideration ventilation in laboratories, occupant densities and location of
standby generators and car parks in the management of AQ on the university campus. All
heating, ventilation and air conditioning (HVAC) systems need to be upgraded and work
in tandem with natural ventilation when having high occupant densities within buildings.
Future studies in this sector could incorporate larger sample sizes, be designed as a
longitudinal study, and make use of questionnaires and sample more AQ parameters to
get a detailed understanding of a university site and its surrounds.Environmental SciencesPh. D. (Environmental Science
The Ecological Factors that Structure the Composition and Function of Saprotrophic Fungi: Observational and Experimental Approaches.
A central goal in ecology is to understand the processes underlying the distribution and abundance of species at local, regional and global scales. As mediators of biogeochemical cycles, understanding the mechanisms that govern microbial community assembly are of ecosystem-scale significance, yet they remain a critical gap in our ecological knowledge. Through a combination of observational and experimental approaches, I explored the roles of selection, drift and dispersal in structuring microbial communities of saprotrophic fungi at a variety of spatial and temporal scales. Furthermore, I investigated the link between fungal community composition and functional characteristics in order to understand whether the factors that structure microbial community assembly have direct consequences to ecological function. First, I explored the role of selection in structuring soil microbial community assembly along a secondary successional chronosequence. My work revealed that the accumulation of organic matter and change in plant litter biochemistry during plant succession (10 to 86 yrs following agricultural abandonment) shaped saprotrophic fungal composition and their physiological potential to metabolize plant detritus, providing support for the idea that changes in plant communities have direct outcomes on the competitive dynamics of saprotrophic microbial communities in soil. Secondly, I found that both dispersal limitation and drift had a persistent effect on the phylogenetic structure and functional richness of saprotrophic fungal communities across a long-term glacial chronosequence (9,500 to 13,500 yrs following glacial retreat). Last, I manipulated initial colonizers and leaf litter biochemistry to understand the relative importance of priority effects and selection in structuring saprotrophic fungal communities and leaf litter decay. I found that the strength of priority effects was dependent on leaf litter biochemistry and physiological traits within a regional species pool. Together, these findings demonstrate that selection, drift and dispersal structure fungal community assembly at both local and regional levels with important consequences to plant litter decay. Furthermore, my observations provide support for the assertion that the same ecological forces structuring plant and animal communities also shape the assembly of saprotrophic fungi.PhDNatural Resources and EnvironmentUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/113471/1/clinela_1.pd
Full Proceedings, 2018
Full conference proceedings for the 2018 International Building Physics Association Conference hosted at Syracuse University
Characterising Indoor Air Quality in UK Homes: A Population-Based Approach
Indoor air quality is of concern in the public health community given the amount of time people are indoors (~90%) and air pollution more generally is linked to a myriad of health issues. The presence of a variety of VOCs, and the subsequent formation of potentially harmful secondary organic aerosols, are of significant concern. This thesis seeks to elucidate some aspects of this complex area of research. First, observing VOC oxidation in chamber experiments has revealed that a number of SOA intermediates form under a variety of oxidant regimes introduced to the chamber, and that these oxidant regimes greatly impact the rate of decay of the parent compound. Further, differing NOx regimes can have a notable impact, such as on VOC decay, and particle and SOA intermediate formation. Secondly, a number of VOCs are found indoors, however, VOC concentrations cannot be linked to the frequency of use of products in the majority of instances, though covariance analysis reveals some weak but statistically significant relationships. Total VOC concentrations provided some insight into potential exposure indoors. Finally, the reactive potential and the pseudo-first order reactivity of VOCs indoors and major indoor oxidants were assessed. The reaction of n-butane and OH was the reaction with the greatest propensity to form secondary products, and whilst OH was significant in many reactions, the abundance of O3 means it too is a significant oxidant indoors. An indoor chemistry model was used to estimate a variety of key components of indoor air, such as particulate matter and OH concentrations, as well as a novel secondary product creation metric. These components were also measured during a COVID-19 lockdown period in 2020, a proxy for future, low NOx scenarios. Together, the elements of this thesis provide a comprehensive analysis to some of the issues surrounding indoor air quality
Recommended from our members
The 21st Annual International Conference on Soils, Sediments and Water
Conference at a Glance Monday, October 17, 2005 Workshops (Workshops #1 and #2: 10:00am - 5:00pm; Workshop #3: 1:00 - 5:00pm; Workshop #4: 1:00 - 3:00pm, Workshop #5: 2:00 - 5:00pm) 1) Theory and Use of Field Portable X-ray Fluorescence for Soil Analysis 2) In-Situ Chemical Oxidation Workshop 3) The Role of Anaerobic Biodegradation Processes in Passive and Enhanced Monitored Natural Attenuation Programs 4) Application of Classic and Emerging Techniques in Environmental Forensics 5) Environmental Fate of Hydrocarbons in Soils and Groundwater Tuesday, October 18, 2005 Platform Presentations 8:30am – Noon Session 1: Environmental Biotechnology Session 2: Ecological Restoration and Natural Treatment Systems Session 3: Pesticides (10:30am – Noon) Session 4: Heavy Metals 1:30 – 5:30pm Session 1: Arsenic Session 2: Bioremediation Session 3: Bioremediation Strategies for Contaminated Soils and Sediments Session 4: Ozone Poster Session 4:00 – 6:00pm, Exhibit Area, First Floor, Campus Center Social 4:30-6:00pm, Exhibit Area, First Floor, Campus Center Workshops 7:00 - 10:00pm 6) Applied Environmental Forensics Workshop 7) Massachusetts Contingency Plan Method 2 Risk Characterizations Wednesday, October 19, 2005 Platform Presentations 8:30am – Noon Session 1: Perchlorate: Emerging Issues and Innovative Remedial Approaches Session 2: Soil Geochemical Background on a Continental Scale Session 3a: Environmental Fate Session 3b: Risk Assessment Session 4: Environmental Stewardship and Proactive Management at Small Arms Ranges 1:30 – 5:30pm Session 1: Ecoterrorism: Research Issues Session 2: Environmental Forensics Session 3a: Legal/Regulatory Session 3b: MTBE Session 4: Bioremediation of Acid Mine Drainage Wastes Poster Session 4:00 – 6:00pm Exhibit Area, First Floor, Campus Center Social 4:30-6:00pm, Exhibit Area, First Floor, Campus Center Workshops 7:00 - 10:00pm 8) In-Situ Thermal Remediation 9) Perchlorate: The Path to Regulatory Standards Setting and Future Assessment & Cleanup Implications 10) NIMS (National Incident Management System) and the Environment Thursday, October 20, 2005 Platform Presentations 8:30am – Noon Session 1: Evolving Strategies for Dealing with Contaminated Sediments Session 2: Pay-for-Performance Remediation Technologies - Methods & Case Studies of Science & Economics Session 3: Phytoremediation Session 4: Site Assessment 1:30 – 5:30pm Session 1: Remediation Session 2: Chemical Oxidation Session 3a: Analysis Session 3b: Indoor Ai
Ammonia
prepared by Syracuse Research Corporation.Chemical manager(s)/author(s): Nickolette Roney, ATSDR, Division of Toxicology, Atlanta, GA; Fernando Llados, Susan S. Little, David B. Knaebel,.Syracuse Research Corporation, North Syracuse, NY."Prepared by Syracuse Research Corporation under contract no. 205-1999-00024; prepared for U.S. Dept. of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry."205-1999-00024Includes bibliographical references and glossary (p. 171-223)
Wildland Fire Smoke in the United States
This open access book synthesizes current information on wildland fire smoke in the United States, providing a scientific foundation for addressing the production of smoke from wildland fires. This will be increasingly critical as smoke exposure and degraded air quality are expected to increase in extent and severity in a warmer climate. Accurate smoke information is a foundation for helping individuals and communities to effectively mitigate potential smoke impacts from wildfires and prescribed fires. The book documents our current understanding of smoke science for (1) primary physical, chemical, and biological issues related to wildfire and prescribed fire, (2) key social issues, including human health and economic impacts, and (3) current and anticipated management and regulatory issues. Each chapter provides a summary of priorities for future research that provide a roadmap for developing scientific information that can improve smoke and fire management over the next decade
Doppler Lidar Vector Retrievals and Atmospheric Data Visualization in Mixed/Augmented Reality
abstract: Environmental remote sensing has seen rapid growth in the recent years and Doppler wind lidars have gained popularity primarily due to their non-intrusive, high spatial and temporal measurement capabilities. While lidar applications early on, relied on the radial velocity measurements alone, most of the practical applications in wind farm control and short term wind prediction require knowledge of the vector wind field. Over the past couple of years, multiple works on lidars have explored three primary methods of retrieving wind vectors viz., using homogeneous windfield assumption, computationally extensive variational methods and the use of multiple Doppler lidars.
Building on prior research, the current three-part study, first demonstrates the capabilities of single and dual Doppler lidar retrievals in capturing downslope windstorm-type flows occurring at Arizona’s Barringer Meteor Crater as a part of the METCRAX II field experiment. Next, to address the need for a reliable and computationally efficient vector retrieval for adaptive wind farm control applications, a novel 2D vector retrieval based on a variational formulation was developed and applied on lidar scans from an offshore wind farm and validated with data from a cup and vane anemometer installed on a nearby research platform. Finally, a novel data visualization technique using Mixed Reality (MR)/ Augmented Reality (AR) technology is presented to visualize data from atmospheric sensors. MR is an environment in which the user's visual perception of the real world is enhanced with live, interactive, computer generated sensory input (in this case, data from atmospheric sensors like Doppler lidars). A methodology using modern game development platforms is presented and demonstrated with lidar retrieved wind fields. In the current study, the possibility of using this technology to visualize data from atmospheric sensors in mixed reality is explored and demonstrated with lidar retrieved wind fields as well as a few earth science datasets for education and outreach activities.Dissertation/ThesisDoctoral Dissertation Mechanical Engineering 201
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