Browsing by Author "Raun, Loren"

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    Association of Out-of-Hospital Cardiac Arrest with Exposure to Fine Particulate and Ozone Ambient Air Pollution from Case-Crossover Analysis Results: Are the Standards Protective?
    (James A. Baker III Institute for Public Policy, 2012) Raun, Loren; Ensor, Katherine B.; James A. Baker III Institute for Public Policy
    About 300,000 cardiac arrests occur outside of hospitals in the United States each year; most are fatal. Studies have shown that a small but significant percentage of cardiac arrests appear to be triggered by exposure to increased levels one of two air pollutants: fine particulate matter and ozone. We analyzed seven key studies to determine if Environmental Protection Agency (EPA) standards protect the public from out-of-hospital cardiac arrests (OHCA) triggered by exposure to fine particulate matter and ozone. Using Houston, Texas, data, we found evidence of an increased risk of cardiac arrest on the order of 2% to 9% due to an increase of fine particulate levels (a daily average increase of 10 µg/m3) on the day of, or day before, the heart attack. The EPA fine particulate standard of 35 µg/m3 (35 micrograms per cubic meter of air) therefore does not effectively protect the public from OHCA triggered by exposure to fine particulates. However, the EPA’s ozone standard does appear to adequately protect public health from OHCA triggered by exposure to ozone.
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    Cross-Disciplinary Consultancy to Enhance Predictions of Asthma Exacerbation Risk in Boston
    (Health Policy and Administration Division UIC School of Public Health, 2016) Reid, Margaret; Gunn, Julia; Shah, Snehal; Donovan, Michael; Eggo, Rosalind; Babin, Steven; Stajner, Ivanka; Rogers, Eric; Ensor, Katherine B.; Raun, Loren; Levy, Jonathan I.; Painter, Ian; Phipatanakul, Wanda; Yip, Fuyuen; Nath, Anjali; Streichert, Laura; Tong, Catherine; Burkom, Howard
    This paper continues an initiative conducted by the International Society for Disease Surveillance with funding from the Defense Threat Reduction Agency to connect near-term analytical needs of public health practice with technical expertise from the global research community. The goal is to enhance investigation capabilities of day-to-day population health monitors. A prior paper described the formation of consultancies for requirements analysis and dialogue regarding costs and benefits of sustainable analytic tools. Each funded consultancy targets a use case of near-term concern to practitioners. The consultancy featured here focused on improving predictions of asthma exacerbation risk in demographic and geographic subdivisions of the city of Boston, Massachusetts, USA based on the combination of known risk factors for which evidence is routinely available. A cross-disciplinary group of 28 stakeholders attended the consultancy on March 30-31, 2016 at the Boston Public Health Commission (BPHC). Known asthma exacerbation risk factors are upper respiratory virus transmission, particularly in school-age children, harsh or extreme weather conditions, and poor air quality. Meteorological subject matter experts described availability and usage of data sources representing these risk factors. Modelers presented multiple analytic approaches including mechanistic models, machine learning approaches, simulation techniques, and hybrids. Health department staff and local partners discussed surveillance operations, constraints, and operational system requirements. Attendees valued the direct exchange of information among public health practitioners, system designers, and modelers. Discussion finalized design of an 8-year de-identified dataset of Boston ED patient records for modeling partners who sign a standard data use agreement.
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    Distributed Hydrologic Modeling of Large Storm Events in the Houston-Galveston Region
    (2013-03-04) Deitz, Roni; Bedient, Philip B; Duenas-Osorio, Leonardo; Raun, Loren
    In conjunction with the SSPEED Center, large rainfall events in the upper Gulf of Mexico are being studied in an effort to help design a surge gate to protect the Houston Ship Channel during hurricane events. When hurricanes hit Galveston Bay, there is a funneling effect and, depending on the track of the hurricane, the storm surge can vary by as much as 5 to 10 feet. For instance, Hurricane Ike produced a surge of about 13 feet in the bay; however, other tracks and higher winds could bring a worst case scenario of 20 to 25 feet of storm surge. Since the Houston Ship Channel is only protected from flooding up to 14-15 feet, and is currently the world’s second largest petrochemical complex, it is critical to understand the linkage between rainfall and storm surge to better protect the region. In this effort, rainfall events in the Houston-Galveston area are being examined. Given the large size of the watersheds flowing from the north and west, statistical methodologies, such as the Probable Maximum Precipitation (PMP) and Precipitation Depth Duration Frequency (PDDF), were employed to better design and predict the shape, pattern, size, and intensity of large rainfall events. Using Hydrometeorological Report (HMR) 52, as well as local hydrologic reports, the 24 hour PMP storm event was created for the upper Gulf of Mexico. In addition, large historic storms, such as Hurricane Ike, and simulated rainfalls from Hurricanes Katrina and Rita, were modeled over the Houston-Galveston region in a hydrologic/hydraulic model with the use of radar and rain gauge data. VfloTM, a distributed hydrologic model was used to model the aforementioned storms. The region was first calibrated to USGS stream gauge data from Greens Bayou Brays Bayou and Peach Creek, and the modeled results accurately depict key features of observed hydrographs, including time to peak, discharge, and the double peak discharge phenomenon caused by double rain bursts. Once calibrated, VfloTM, is used to quantify the effect that storm size, intensity, and location has on timing and peak flows in the upper drainage area. Results indicate that there is a double peak phenomenon with flows from the west draining earlier than flows from the north. With storm surge typically lasting 36-48 hours, this indicates the flows from the west and north are interacting with storm surge, with flows from the west arriving before flows from the north downstream. Gate operations were optimized in the model to account for the relative timing of upland runoff and hurricane surge, as well as the capability of the gate structure to protect the Ship Channel industry was quantified.
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    Sensitivities of Biogenic Volatile Organic Compounds to Climatological Factors Affected by Drought
    (2015-03-27) Chavez-Figueroa, Erin Michelle; Cohan, Daniel S; Griffin, Rob; Raun, Loren
    Drought is expected to increase in both intensity and duration in our changing climate. However, the combined effects of drought conditions on the emissions of biogenic volatile organic compounds (BVOC) from vegetation are uncertain due to contradictory responses to the individual drought components. While increased temperature causes an increase in emissions, for instance, low enough soil moisture causes a decrease. This study therefore explored the impacts of variations in individual climate conditions on BVOC emissions. The sensitivity of BVOC emissions to leaf area index (LAI), photosynthetically active radiation (PAR), temperature, and precipitation were assessed using both ground measurements and the model MEGAN. While variations in PAR and LAI were less important than temperature in explaining variation in BVOC emissions, the choice of input data proved important. Satellite PAR produced lower isoprene emissions estimates than PAR generated by the meteorological model WRF. Higher resolution LAI data produced more spatial variability in isoprene emissions estimates. Drought was not found to correspond well to BVOC emissions, with temperature providing a much better predictor of emissions at a given location.