Report - Agence canadienne d'évaluation environnementale

Impacts on the inhabited area and human activities
PM2.5; and two stations in urban residential districts, Saint-Charles-Garnier (O3 and
PM2,5) and De l’Église (TPM). Two other stations were included: one in a forest
setting, Notre-Dame-du-Rosaire (TSP, PM2.5 and O3); and the other in an agricultural
area, Saint-François-de-L’Île-d’Orléans (O3).
♦ Finding — The Panel notes that the current air quality in the proposed project
development area has not been caracterized. Rather, it was estimated using data
gathered at monitoring stations operated by the ministère du Développement durable,
de l’Environnement et des Parcs in the city of Québec and surrounding areas.
Project impact on air quality
The proponent simulated by computer the project’s contribution to concentrations of
contaminants in the air using atmospheric dispersion models recognized by the
MDDEP. These models integrate data relevant to the characteristics of emission
sources, meteorological data, traffic movements, and the characteristics of receptors,
i.e. points on the ground where the concentration of pollutants is calculated using
computerized mathematical models. The main goal of the simulations is to predict that
concentrations of pollutants emitted by one or several new sources will not exceed
standards, if the project is completed.
Construction phase
The proponent identified the main sources for emission of airborne pollutants on the
construction site and around it during the anticipated two years of construction, i.e.
2007 and 2008. The proponent retained the following sources: exhaust gases from
vehicles and machinery, dust rose by transportation traffic on the roads, whether
paved or not, the handling of backfill material and excavation by blasting for land
facilities and the utility corridor leading to the jetty; and, finally, cement mixing plants
on the construction site itself.
According to the impact statement, the results obtained are based on the assumption
that construction site machinery will run continually at full capacity during the life of
the construction site , and that the maximum number of vehicles going to the site on
an access road via Lallemand Road will be attained every day. As a precautionary
measure, the modelling are based on the highest reference thresholds and take into
account meteorological conditions most unfavourable to the atmospheric dispersion of
pollutants. The projected maximum concentrations in the ambient air, if the
construction of the proposed facilities proceeds, are presented in Table 13. The
computer model data for the home closest to the construction site show that
cumulation of maximum concentrations of pollutants during construction and
contaminants in the air (baseline) would respect the RQA and the PRAA standards.
188 Rabaska Project – Implementation of an LNG Terminal and Related Infrastructure