Evaluations of benzene impacts of a coke plant in a complex-topography urban area with the RAMS-CALMET-CALPUFF modelling system

Abstract

The RAMS-CALMET-CALPUFF modelling system, together with observations, has been used to analyse the benzene impacts of a coke plant located in a narrow river valley over a nearby urban area in the estuary of Bilbao. The initial aim of this study was to set up a methodology suitable for dispersion studies in very complex areas, where pollutant dynamics are highly affected by mesoscale processes. Emphasis was put on the validation and improvement of the simulated meteorology. High spatio-temporal resolution meteorological simulations were performed with the non-hydrostatic mesoscale meteorological model RAMS, initialized with NCEP reanalysis data, for two ten-day periods. Results were validated against data recorded both at surface stations and by a wind profiler radar (WPR). Comparisons against the WPR revealed inaccurate NCEP data for one of the periods. Alternative nudging with ECMWF ERA-Interim data improved the results. The RAMS output was downscaled from 1 km to 250 m resolution with the CALMET diagnostic model. The main flows that affect dispersion in the area were mostly well simulated, but important disagreements with observed drainage flows were found for some days. The assimilation of surface meteorological observations into CALMET, greatly improved the results. The meteorological fields were input into the CALPUFF non-steady-state puff dispersion model for dispersion simulations. The actual daily cycles of ground level benzene were well reproduced but concentration levels were underestimated. The availability of good meteorological observations in the area and good emission inventory has shown to be of prime importance.

Modelling the dispersion of benzene emissions from a proposed ethanol producing facility in Farewell-Oshawa of Toronto, Canada

“…In this study, benzene concentration over a 24-hour period of exposure is simulated by the CALPUFF modelling system, CALPro software (CALPro Plus V6.9.10.25.2007). The simulation package consists of a pre-processing (CALMET), a simulation (CALPUFF), and a post-processing package (CALPOST/PRTMET) with their respective graphical user interfaces (Valdenebro et al, 2013). Before any package is used, a set of commonly shared information must be entered.…”

“…CALPUFF, a non-steady-state Lagragian Gaussian puff model, was chosen over other modelling software such as AERMOD, the Buoyant Line and Point (BLP) source dispersion model, and the third generation California Line Source Dispersion Model (CALINE3) because, unlike these models, CALPUFF does not use steady state assumptions to model plume trajectories from a point source (The Atmospheric Studies Group, 2013). Other research papers have used CALPUFF to model the ambient concentrations of benzene from other sources such as vehicle emissions (Cohen et al, 2005) and from a coke plant (Valdenebro et al, 2013). In the current study, CALPUFF was used extensively to model the ambient benzene concentrations over a 24-hour period of exposure, whilst taking into consideration the effect of pollutant transformation and removal, and meteorological factors such as wind direction and speed, and temperature.…”

Spatial distribution and source analysis of SO2 concentration in Urumqi

“…Prueksakorn et al (2014) applied WRF/CALPUFF modeling system and multimonitoring methods to investigate the effect of seasonal variations on odor dispersion in Changwon City of South Korea [4]. Valdenebro et al (2013) applied RAMS-CALMET-CALPUFF modeling system to evaluate the benzene impacts of a coke plant in a complex-topography urban area in Spain [5]. Ozkurt et al (2013) applied CALPUFF to evaluate the impact of SO 2 and NO 2 emissions on the ambient air-quality in the Can-Bayramic region of northwest Turkey [6].…”