# Presentation: 525692

## Revisiting Canadian Air Quality Indices: a Health Risk Based Approach 

**Dave Henderson, Dave Stieb and Philip Blagden**
***Air Quality and Health: Making the Connection***
**EPA Air Now, San Francisco**
**February 13, 2005**

## The AQI Conundrum

***"About 92% of the premature deaths and hospitalizations attributable to air pollution in Toronto occur when the air quality has been classified as good or very good by the provincial AQI."***** **
**Toronto Public Health's 2001 report (Condition Critical: Fixing Our Smog Warning System)**

## National AQI Process and Participation

**Fall 2001 a multi-stakeholder process was set up to develop an improved Canadian AQI **
**Direction from stakeholder input **
**Investigated the applicability of existing sub-indices based international AQIs. e.g. **
**US EPA**
**UK**
**Looked at ways of updating the existing AQIs **
**Using the new Canada Wide Standards**

## Analysis of Sub-indices Based Canadian AQIs

**Advantages: **
**Relates to air quality management targets**
**Can be calculated with data for one or more pollutants**
**Either ozone or PM determine the AQI most of the time**
**Disadvantages**
**Based on outdated science**
**No way of effectively comparing AQ in different regions**
**Implication of thresholds**
**Weighting of pollutants based on targets, not risk **
**Does not account for combined impact of pollutants**
**Differences in indices have become more noticeable with real-time reporting, websites, and forecasting**

## Vision for an Improved AQI

**A vision developed for a**** multi-pollutant, health-risk based index**
**Communications tool for real time and forecasts **
**Aggregate estimate of health risk from air pollution**
**Not threshold based **
**Shorter time averages**** **
**Supported by health action messaging **
**What it is not**** **
**A tool for determining trends**
**A measure of standards achievements or determining compliance**
**No a priori point for issuing AQ advisories**** **

## Our Approach to a Health Risk Based Index

**Focus on acute impacts**
**Consideration of multiple health endpoints **
**Based on time series analyses**
**Focus on Canadian data **
**Multiple pollutants **

## Health Effects of Air Pollution

-   ***hospital***
***admissions***

***death***

***Air pollution is a causative factor in thousands of mortalities and hospital admissions for cardiac and respiratory illness***

## Results of Health Analysis 

**Relative risk from mortality data reflect risk for the broad range of health outcomes **
**Consistency across times series studies **
**risk estimates agree with international meta analysis **
**Current risk formulation composed of O****3****, PM****2.5****, NO****2**** and SO****2**
**Dropped CO **
**3 hour rolling averages for pollutants **
**Derived through statistical correlations**
**Choice of a 0-10 unbounded scale**

## Calculating the AQI

## National AQI Reference Distribution

## Simulation of the Health Risk based AQI Hamilton, Ontario October, 2003(courtesy Ontario Ministry of the Environment) 

## Health Messaging and AQI Presentation

**Multi-pollutant messages**
**Descriptive and prescriptive messaging**
**Message development being informed by: **
**Past public opinion surveys and research**
**Public opinion research **
**Mental models work**
**Stakeholder health messages workshop – Dec 2-3, 2005**
**Focus testing (5 cities in Feb 2005)**
**Value in name change from AQI **

## Ongoing Challenges 

**How to forecast for all of the pollutants in the index?**
**National O****3**** capacity**** **
**Emerging capacity for national PM****2.5**** **
**Currently no capacity to forecast NO****2**** and SO****2  **

## 4 Pollutant AQI ForecastAURAMS model

## Forecasting for NO2 and SO24 –2 Pollutant Difference from AURAMS model

## Ongoing Challenges 

**How to forecast for all of the pollutants in the index?**
**How to deal with sites which do not have all 4 continuously monitored pollutants?**

## Protocol for Missing Pollutants

## Ongoing Challenges 

**How to forecast for all of the pollutants in the index?**
**How to deal with sites which do not have all 4 continuously monitored pollutants?**
**Index Transitions **
**outreach**
**Parallel Compliance and Health Protection tools**
**Coherent AQ information in border areas**
**Accommodating regional flexibility within a national framework**

## Path Forward

**Winter/Spring 2005**
**Focus testing of health messages and AQI presentation**
**Late Spring **
**Draft of a AQI Science Assessment document  (peer reviewed)**
**Summer 2005**** **
**Possible Pilots of the new AQI (in 3 locations)**
**Late Fall 2005**
**Draft AQI Guidance document for Regions **
**Spring 2006 – Winter 2006**
**Shadow program in AQI jurisdictions**
**?**

## Opportunities

**Window of Opportunity for cross-border collaboration**
**Harmonization of air quality information in border regions **
**health messages in border regions **
**Scientific exchange (health, monitoring, etc.)**
**Sharing Communications and outreach expertise**