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A. Ciccone et al.
19.1 Introduction
The objective of this study is to develop and implement the Hamilton Airshed Modelling System (HAMS), which will provide a platform to better understand the processes and contributions to Hamilton’s air quality and aid to inform future policy
and human health impact decisions. Air quality in an urban airshed is influenced by
local, regional and transboundary sources, as well as by the geographical features and
prevailing meteorological conditions. An airshed modelling system must be capable of handling the different emission sources, the complex meteorology, and the
transportation and dispersion of emissions to achieve realistic simulations of local
impacts on air quality.
The air quality in the Hamilton Region was modelled by tracking the emission, dispersion and chemical transformation of twenty selected contaminants in the airshed,
with a focus on NO X , SO 2 , O 3 and particulate matter (PM 2.5 and PM 10 ). Emphasis
was also placed on benzene and benzo(a)pyrene (B[a]P) for health and regulatory
reasons. The modelling is completed using four levels of nested spatial grids, providing both regional and local contributions to the air quality. The Hamilton airshed is
part of the larger southern Ontario airshed, with influences from both south-western
Ontario and the United States. The influences each have different emission profiles
with respect to contaminants, quantity of emissions, and types of sources (e.g., stacks,
roadways, area), as well as the specific location of the sources.
19.2 Modelling System Description
The HAMS relies on the development of two key data sets: meteorology and emissions. To represent the transport, and aid in the representation of the chemical transformation, dispersion and deposition of pollutants, a meteorological data set is needed,
which will include the unique and challenging influences of the terrain in the Hamilton area. To represent the sources and compounds influencing air quality, an emissions
inventory is required which includes both local and regional sources and accounts
for contributions from human-made and natural sources.
The Weather Research and Forecasting (WRF) Nonhydrostatic Mesoscale Model
(NMM) model version 3.6.1 [3] was selected to generate 3-dimenisional hourly
meteorological data for the dispersion and chemical modelling. Detailed analysis
demonstrated that WRF did well at replicating observed atmospheric values of temperature, mixing ratio, wind speed and wind direction. Monthly and annual analyses
demonstrated a high level of accuracy in reproducing observations, even in the region
surrounded by the Great Lakes (Tier IV).
Gridded, hourly emissions estimates of speciated compounds were prepared primarily with the Sparse Matrix Operator Kernel Emissions version 3.6 (SMOKE v3.6)
[2] for emission and source data including: human-made emissions data covering
A. Ciccone et al.
19.1 Introduction
The objective of this study is to develop and implement the Hamilton Airshed Modelling System (HAMS), which will provide a platform to better understand the processes and contributions to Hamilton’s air quality and aid to inform future policy
and human health impact decisions. Air quality in an urban airshed is influenced by
local, regional and transboundary sources, as well as by the geographical features and
prevailing meteorological conditions. An airshed modelling system must be capable of handling the different emission sources, the complex meteorology, and the
transportation and dispersion of emissions to achieve realistic simulations of local
impacts on air quality.
The air quality in the Hamilton Region was modelled by tracking the emission, dispersion and chemical transformation of twenty selected contaminants in the airshed,
with a focus on NO X , SO 2 , O 3 and particulate matter (PM 2.5 and PM 10 ). Emphasis
was also placed on benzene and benzo(a)pyrene (B[a]P) for health and regulatory
reasons. The modelling is completed using four levels of nested spatial grids, providing both regional and local contributions to the air quality. The Hamilton airshed is
part of the larger southern Ontario airshed, with influences from both south-western
Ontario and the United States. The influences each have different emission profiles
with respect to contaminants, quantity of emissions, and types of sources (e.g., stacks,
roadways, area), as well as the specific location of the sources.
19.2 Modelling System Description
The HAMS relies on the development of two key data sets: meteorology and emissions. To represent the transport, and aid in the representation of the chemical transformation, dispersion and deposition of pollutants, a meteorological data set is needed,
which will include the unique and challenging influences of the terrain in the Hamilton area. To represent the sources and compounds influencing air quality, an emissions
inventory is required which includes both local and regional sources and accounts
for contributions from human-made and natural sources.
The Weather Research and Forecasting (WRF) Nonhydrostatic Mesoscale Model
(NMM) model version 3.6.1 [3] was selected to generate 3-dimenisional hourly
meteorological data for the dispersion and chemical modelling. Detailed analysis
demonstrated that WRF did well at replicating observed atmospheric values of temperature, mixing ratio, wind speed and wind direction. Monthly and annual analyses
demonstrated a high level of accuracy in reproducing observations, even in the region
surrounded by the Great Lakes (Tier IV).
Gridded, hourly emissions estimates of speciated compounds were prepared primarily with the Sparse Matrix Operator Kernel Emissions version 3.6 (SMOKE v3.6)
[2] for emission and source data including: human-made emissions data covering