AQHI updates by expanding temporal and spatial coverage

The Air Quality Health Index (AQHI) is a communication tool, which sums the individual risksassociated with ozone (O3), nitrogen dioxide (NO2) and fine particulate matter (PM2.5), toprovide guidance to the public on protecting their health from the adverse health effect of outdoor air pollution. The current AQHI is reported in individual communities based on local air pollution concentrations applied to model parameters derived from national analyses. Here the parameters are the relative risk of the three air pollutants, ground-level ozone, NO2, and PM2.5, nationwide and thus to be estimated by all cities included. The assumption of this approach is: the impact of air pollutant on public health is the same across Canada regardless of the differences between geographical locations. The model parameter indicates this impact per unit of each pollutant, and thus should be the same for all Canadian cities. However, each city has different concentrations and environmental background (e.g., temperature), and thus using local concentrations with the national parameter estimates would show the local impact in total (not per unit). This approach depends on the number of cities included and the number of years examined as indicated by the three objectives.Updates to the AQHI are required in three areas. First, the current AQHI does not fully represent the effect of the combined exposures on health due to interactions among the three air pollutants. Second, the current AQHI is based on major urban centres only, due to air pollution data availability. The AQHI is designed for national usage and thus expanding to rural areas and smaller urban areas is desirable. Third, the current AQHI is based on data for 1991-2000. The Canadian demographic profile, air quality profile, and medical care have changed since 2000, which may change the exposure-health outcome relationship over time and thus expansion to recent years is also necessary.Previous projects developed new models for the combined risk from the three pollutants, which are expected to resolve the first need. Recently Environment and Climate Change Canada (ECCC) has provided hourly or daily modelled data from Objective Analysis across Canada, including rural areas, which will be enhanced further and available in 2020 and a new national forest fire smoke model will be developed under another project entitled “Development of a national forest fire smoke PM2.5 exposure model” (Stieb), and thus resolve the second need. Currently (as of Jan 2018) health data are available up to 2012 for mortality and 2015 forhospitalization except for province Quebec. By adding 12-15 recent years, the AQHI can beupdated, resolving the third need. The project objective is to address three concerns related to the AQHI updates:(1) improving statistical model to account for correlations among the three specified airpollutants;(2) extending spatial coverage to include rural areas; and(3) extending temporal coverage to include more recent years