N Scott

Air quality and exercise-related health benefits from reduced car travel in the midwestern United States.

Background: Automobile exhaust contains precursors to ozone and fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter; PM2.5), posing health risks. Dependency on car commuting also reduces physical fitness opportunities. Objective: In this study we sought to quantify benefits from reducing automobile usage for short urban and suburban trips. Methods: We simulated census-tract level changes in hourly pollutant concentrations from the elimination of automobile round trips ≤ 8 km in 11 metropolitan areas in the upper midwestern United States using the Community Multiscale Air Quality (CMAQ) model. Next, we estimated annual changes in health outcomes and monetary costs expected from pollution changes using the U.S. Environmental Protection Agency Benefits Mapping Analysis Program (BenMAP). In addition, we used the World Health Organization Health Economic Assessment Tool (HEAT) to calculate benefits of increased physical activity if 50% of short trips were made by bicycle. Results: We estimate that, by eliminating these short automobile trips, annual average urban PM2.5 would decline by 0.1 µg/m3 and that summer ozone (O3) would increase slightly in cities but decline regionally, resulting in net health bene-fits of

Is Compact Growth Good for Air Quality

4.94 billion/year [95% confidence interval (CI):

Change in ozone air pollution over Chicago associated with global climate change

0.2 billion,

Abiotic mechanism for the formation of atmospheric nitrous oxide from ammonium nitrate.

13.5 billion), with 25% of PM2.5 and most O3 bene-fits to populations outside metropolitan areas. Across the study region of approximately 31.3 million people and 37,000 total square miles, mortality would decline by approximately 1,295 deaths/year (95% CI: 912, 1,636) because of improved air quality and increased exercise. Making 50% of short trips by bicycle would yield savings of approximately

Estimating the health benefits from natural gas use in transport and heating in Santiago, Chile.

3.8 billion/year from avoided mortality and reduced health care costs (95% CI:

Simulating and Explaining Passive Air Sampling Rates for Semivolatile Compounds on Polyurethane Foam Passive Samplers

2.7 billion,

Seasonality of speciated aerosol transport over the Great Lakes region

5.0 billion]. We estimate that the combined benefits of improved air quality and physical fitness would exceed

Improving aerosol distributions below clouds by assimilating satellite-retrieved cloud droplet number

8 billion/year. Conclusion: Our findings suggest that significant health and economic benefits are possible if bicycling replaces short car trips. Less dependence on automobiles in urban areas would also improve health in downwind rural settings.

Variations of Flame Retardant, Polycyclic Aromatic Hydrocarbon, and Pesticide Concentrations in Chicago's Atmosphere Measured using Passive Sampling.

Abstract Problem: Explicitly prohibited from regulating the land use planning activities of municipal and county governments by the Clean Air Act (42 U.S.C. 131), the U.S. Environmental Protection Agency (EPA) has been forced to pursue an end-of-the-pipe approach to air quality management that has not proved successful in fully reducing ozone and fine particulate matter below health-based standards in many large U.S. cities. The persistence of these pollutants, in combination with a rapid rise in vehicle travel in recent decades, has raised concerns within the planning and public health communities about the long-term success of an air quality management program that is effectively divorced from the land use planning process. Purpose: This work, which is part of an EPA-sponsored study titled Projecting the Impact of Land Use and Transportation on Future Air Quality (PLUTO), was intended to assess the effectiveness of compact growth in improving air quality at a geographic scale compatible with secondary pollution formation and transport and over a planning horizon sufficient to capture the longer-term benefits of regional land use change. Methods: Future air quality is associated with alternative land development scenarios in this study through the integration of three separate and previously unrelated modeling components. These components consist of a set of standard population projection techniques, a household vehicle travel activity framework, and a mobile source emissions model (MOBILE 6) developed by the EPA. Results and conclusions: The results of our analysis find the median elasticity of vehicle travel with respect to density change over time to be −0.35, suggesting metropolitan areas can expect a 10% increase in population density to be associated with a 3.5% reduction in household vehicle travel and emissions. In addition, vehicle elasticities derived for urban and suburban census tracts across the 11 metro regions suggest density increments within urban zones (−0.43) to be more than twice as effective in reducing vehicle travel and emissions as density increments within suburban zones (−0.19). Takeaway for practice: We found compactness to be associated with greater reductions in vehicle travel than in previous studies, which suggests land use change can play a measurable role in improving regional air quality over time. Importantly, we found where compact growth occurs to be critically important to determining the extent to which higher density development reduces vehicle travel and emissions. We found the densifi-cation of urban zones to be more than twice as effective in reducing vehicle miles of travel and emissions as the densification of suburban zones, suggesting compact growth to be better for air quality than historical patterns of growth when densifying urban zones is given priority over non-urban zones.

Modeled aerosol nitrate formation pathways during wintertime in the Great Lakes region of North America

[1]xa0This study uses statistical downscaling to estimate the impact of future climate change on air quality. We employ historical observations of surface ozone (O3) over the Chicago area, large-scale climate variables from the National Center for Environmental Protection (NCEP) reanalysis data, and climate projections from three GCMs (GFDL, PCM, and HadCM3), driven by two SRES emission scenarios (A1FI and B1 for GFDL and PCM; A2 and B1 for HadCM3). This approach calculates historic relationships between meteorology and O3, and considers how future meteorology would affect ground-level O3 if these relationships remain constant. Ozone mixing ratios over Chicago are found to be most sensitive to surface temperature, horizontal surface winds, surface relative humidity, incoming solar radiation, and cloud cover. Considering the change in O3 due to global climate change alone, summertime (June, July, and August) mean mixing ratios over Chicago are projected to increase by 6–17 ppb by the end of the century, depending on assumptions about global economic growth and choice of GCM. Changes are greater under higher climate emissions scenarios and more sensitive climate models (e.g. 24 ppb for GFDL A1FI as compared to 2 ppb for PCM B1). However, this approach does not take into account changes in O3-precursor emissions nor changes in local and lake-effect meteorology, which could combine with climate change to either enhance or diminish the projected change in local mixing ratios. Statistical downscaling is performed with the Statistical DownScaling Model (SDSM v. 4.1, a publicly available scientific analysis and decision-support tool.