Medicine and Health Sciences Commons^™

Investigation Of The Correlation Between Odd Oxygen And Secondary Organic Aerosol In Mexico City And Houston, Ezra Wood, M. Canagaratna, S. Herndon, J. Kroll, T. Onasch, C. Kolb, D. Worsnop, W. Knighton, R. Seila, M. Zavala, L. Molina, P. Decarlo, J. Jimenez, A. Weinheimer, D. Knapp, B. Jobson, J. Stutz, W. Kuster, E. Williams

Public Health Department Faculty Publication Series

Many recent models underpredict secondary organic aerosol (SOA) particulate matter (PM) concentrations in polluted regions, indicating serious deficiencies in the models' chemical mechanisms and/or missing SOA precursors. Since tropospheric photochemical ozone production is much better understood, we investigate the correlation of odd-oxygen ([Ox]≡[O3]+[NO2]) and the oxygenated component of organic aerosol (OOA), which is interpreted as a surrogate for SOA. OOA and Ox measured in Mexico City in 2006 and Houston in 2000 were well correlated in air masses where both species were formed on similar timescales (less than 8 h) and not well correlated when their formation timescales or location …

Application Of Quantum Cascade Lasers To High-Precision Atmospheric Trace Gas Measurements, Ezra Wood, J. Barry Mcmanus, Mark Zahniser, David Nelson, Joanne Shorter, Scott Herndon, Rick Wehr

Public Health Department Faculty Publication Series

We review our recent results in development of high-precision laser spectroscopic instrumentation using midinfrared quantum cascade lasers (QCLs). Some of these instruments have been directed at measurements of atmospheric trace gases where a fractional precision of 10−3 or better of ambient concentration may be required. Such high precision is needed in measurements of fluxes of stable atmospheric gases and measurements of isotopic ratios. Instruments that are based on thermoelectrically cooled midinfrared QCLs and thermoelectrically cooled detectors have been demonstrated that meet the requirements of high-precision atmospheric measurements, without the need for cryogens. We also describe the design of and results …

Application Of Positive Matrix Factorization To On-Road Measurements For Source Apportionment Of Diesel- And Gasoline-Powered Vehicle Emissions In Mexico City, D. Thornhill, A. Williams, T. Onasch, Ezra Wood, S. Herndon, C. Kolb, W. Knighton, M. Zavala, L. Molina, L. Marr

Public Health Department Faculty Publication Series

The goal of this research is to quantify diesel- and gasoline-powered motor vehicle emissions within the Mexico City Metropolitan Area (MCMA) using on-road measurements captured by a mobile laboratory combined with positive matrix factorization (PMF) receptor modeling. During the MCMA-2006 ground-based component of the MILAGRO field campaign, the Aerodyne Mobile Laboratory (AML) measured many gaseous and particulate pollutants, including carbon dioxide, carbon monoxide (CO), nitrogen oxides (NOx), benzene, toluene, alkylated aromatics, formaldehyde, acetaldehyde, acetone, ammonia, particle number, fine particulate mass (PM2.5), and black carbon (BC). These serve as inputs to the receptor model, which is able to resolve three factors …

Automated Detection Of Infectious Disease Outbreaks In Hospitals: A Retrospective Cohort Study, Susan S. Huang, Deborah S. Yokoe, John Stelling, Hilary Placzek, Martin Kulldorff, Ken Kleinman, Thomas F. O'Brien, Michael S. Calderwood, Johanna Vostok, Julie Dunn, Richard Platt

Public Health Department Faculty Publication Series

BACKGROUND:

Detection of outbreaks of hospital-acquired infections is often based on simple rules, such as the occurrence of three new cases of a single pathogen in two weeks on the same ward. These rules typically focus on only a few pathogens, and they do not account for the pathogens' underlying prevalence, the normal random variation in rates, and clusters that may occur beyond a single ward, such as those associated with specialty services. Ideally, outbreak detection programs should evaluate many pathogens, using a wide array of data sources.

METHODS AND FINDINGS:

We applied a space-time permutation scan statistic to microbiology …

Short-Term Variation In Near-Highway Air Pollutant Gradients On A Winter Morning, J. Durant, C. Ash, Ezra Wood, S. Herndon, J. Jayne, W. Knighton, M. Canagaratna, J. Trull, D. Brugge, W. Zamore, C. Kolb

Public Health Department Faculty Publication Series

Quantification of exposure to traffic-related air pollutants near highways is hampered by incomplete knowledge of the scales of temporal variation of pollutant gradients. The goal of this study was to characterize short-term temporal variation of vehicular pollutant gradients within 200–400 m of a major highway (>150 000 vehicles/d). Monitoring was done near Interstate 93 in Somerville (Massachusetts) from 06:00 to 11:00 on 16 January 2008 using a mobile monitoring platform equipped with instruments that measured ultrafine and fine particles (6–1000 nm, particle number concentration (PNC)); particle-phase (>30 nm) equation M1, equation M2, and organic compounds; volatile organic compounds …

Use Of Outcomes To Evaluate Surveillance Systems For Bioterrorist Attacks, Kerry A. Mcbrien, Ken P. Kleinman, Allyson M. Abrams, Lisa A. Prosser

Public Health Department Faculty Publication Series

Background

Syndromic surveillance systems can potentially be used to detect a bioterrorist attack earlier than traditional surveillance, by virtue of their near real-time analysis of relevant data. Receiver operator characteristic (ROC) curve analysis using the area under the curve (AUC) as a comparison metric has been recommended as a practical evaluation tool for syndromic surveillance systems, yet traditional ROC curves do not account for timeliness of detection or subsequent time-dependent health outcomes.

Methods

Using a decision-analytic approach, we predicted outcomes, measured in lives, quality adjusted life years (QALYs), and costs, for a series of simulated bioterrorist attacks. We then evaluated …

Evidence That Pneumococcal Serotype Replacement In Massachusetts Following Conjugate Vaccination Is Now Complete, William P. Hanage, Jonathan A. Finkelstein, Susan S. Huang, Stephen I. Pelton, Abbie E. Stevenson, Ken Kleinman, Virginia L. Hinrichsen, Christophe Fraser

Public Health Department Faculty Publication Series

Invasive pneumococcal disease (IPD) has been reduced in the US following conjugate vaccination (PCV7) targeting seven pneumococcal serotypes in 2000. However, increases in IPD due to other serotypes have been observed, in particular 19A. How much this "serotype replacement" will erode the benefits of vaccination and over what timescale is unknown. We used a population genetic approach to test first whether the selective impact of vaccination could be detected in a longitudinal carriage sample, and secondly how long it persisted for following introduction of vaccine in 2000. To detect the selective impact of the vaccine we compared the serotype diversity …