Abstract

The effects of urbanization on ozone levels have been widely investigated over cities primarily located in temperate and/or humid regions. In this study, nested WRF-Chem simulations with a finest grid resolution of 1 km are conducted to investigate ozone concentrations [O<inf>3</inf>] due to urbanization within cities in arid/semi-arid environments. First, a method based on a shape preserving Monotonic Cubic Interpolation (MCI) is developed and used to downscale anthropogenic emissions from the 4 km resolution 2005 National Emissions Inventory (NEI05) to the finest model resolution of 1 km. Using the rapidly expanding Phoenix metropolitan region as the area of focus, we demonstrate the proposed MCI method achieves ozone simulation results with appreciably improved correspondence to observations relative to the default interpolation method of the WRF-Chem system. Next, two additional sets of experiments are conducted, with the recommended MCI approach, to examine impacts of urbanization on ozone production: (1) the urban land cover is included (i.e., urbanization experiments) and, (2) the urban land cover is replaced with the region's native shrubland. Impacts due to the presence of the built environment on [O<inf>3</inf>] are highly heterogeneous across the metropolitan area. Increased near surface [O<inf>3</inf>] due to urbanization of 10-20 ppb is predominantly a nighttime phenomenon while simulated impacts during daytime are negligible. Urbanization narrows the daily [O<inf>3</inf>] range (by virtue of increasing nighttime minima), an impact largely due to the region's urban heat island. Our results demonstrate the importance of the MCI method for accurate representation of the diurnal profile of ozone, and highlight its utility for high-resolution air quality simulations for urban areas.

Original languageEnglish (US)
Article number114019
JournalEnvironmental Research Letters
Volume9
Issue number11
DOIs
StatePublished - Nov 1 2014

Fingerprint

Urbanization
Ozone
urbanization
Interpolation
ozone
interpolation
simulation
land cover
Air quality
urban region
heat island
arid environment
emission inventory
shrubland
metropolitan area
Experiments
air quality
Hot Temperature
urban area
experiment

Keywords

  • air quality
  • arid city
  • modeling
  • ozone change
  • urban heat island
  • urbanization
  • WRF-Chem

ASJC Scopus subject areas

  • Environmental Science(all)
  • Renewable Energy, Sustainability and the Environment
  • Public Health, Environmental and Occupational Health

Cite this

Achieving accurate simulations of urban impacts on ozone at high resolution. / Li, J.; Georgescu, Matei; Hyde, P.; Mahalov, Alex; Moustaoui, Mohamed.

In: Environmental Research Letters, Vol. 9, No. 11, 114019, 01.11.2014.

Research output: Contribution to journalArticle

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