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Air-quality implications of widespread adoption of cool roofs on ozone and particulate matter in southern California.

ABSTRACT: The installation of roofing materials with increased solar reflectance (i.e., "cool roofs") can mitigate the urban heat island effect and reduce energy use. In addition, meteorological changes, along with the possibility of enhanced UV reflection from these surfaces, can have complex impacts on ozone and PM_2.5 concentrations. We aim to evaluate the air-quality impacts of widespread cool-roof installations prescribed by California's Title 24 building energy efficiency standards within the heavily populated and polluted South Coast Air Basin (SoCAB). Development of a comprehensive rooftop area database and evaluation of spectral reflectance measurements of roofing materials allows us to project potential future changes in solar and UV reflectance for simulations using the Weather Research Forecast and Community Multiscale Air Quality (CMAQ) models. 2012 meteorological simulations indicate a decrease in daily maximum temperatures, daily maximum boundary layer heights, and ventilation coefficients throughout the SoCAB upon widespread installation of cool roofs. CMAQ simulations show significant increases in PM_2.5 concentrations and policy-relevant design values. Changes in 8-h ozone concentrations depend on the potential change in UV reflectance, ranging from a decrease in population-weighted concentrations when UV reflectance remains unchanged to an increase when changes in UV reflectance are at an upper bound. However, 8-h policy-relevant ozone design values increase in all cases. Although the other benefits of cool roofs could outweigh small air-quality penalties, UV reflectance standards for cool roofing materials could mitigate these negative consequences. Results of this study motivate the careful consideration of future rooftop and pavement solar reflectance modification policies.

SUBMITTER: Epstein SA

PROVIDER: S-EPMC5576793 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature

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Air-quality implications of widespread adoption of cool roofs on ozone and particulate matter in southern California.

Epstein Scott A SA Lee Sang-Mi SM Katzenstein Aaron S AS Carreras-Sospedra Marc M Zhang Xinqiu X Farina Salvatore C SC Vahmani Pouya P Fine Philip M PM Ban-Weiss George G

Proceedings of the National Academy of Sciences of the United States of America 20170807 34

The installation of roofing materials with increased solar reflectance (i.e., "cool roofs") can mitigate the urban heat island effect and reduce energy use. In addition, meteorological changes, along with the possibility of enhanced UV reflection from these surfaces, can have complex impacts on ozone and PM<sub>2.5</sub> concentrations. We aim to evaluate the air-quality impacts of widespread cool-roof installations prescribed by California's Title 24 building energy efficiency standards within ...[more]

PMID: 28784778

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Dataset Information

Air-quality implications of widespread adoption of cool roofs on ozone and particulate matter in southern California.

Publications

Air-quality implications of widespread adoption of cool roofs on ozone and particulate matter in southern California.

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