Canada-United States Border Air Quality Strategy: Georgia Basin Puget Sound International Airshed Strategy

In support of this pilot project under the Canada-United States Border Air Quality Strategy, Health Canada is working with the British Columbia Centre for Disease Control and the Universities of British Columbia, Victoria and Washington to fill knowledge gaps about health issues related to pollution sources such as transportation, marine and wood smoke emissions in the Georgia Basin/Puget Sound airshed region.

While air quality in BC's Georgia Basin and Washington's Puget Sound generally meets relevant standards, there is a pressing need to "keep clean areas clean" by anticipating and addressing the potential negative impacts of future growth in an area where the population is expected to grow from six to nine million by 2020. Recent research findings also show that air quality continues to have negative health impacts in this region even when standards are met.

Regional experts, therefore, are using cutting-edge research techniques to more accurately assess the negative impacts of air pollution on vulnerable populations. For the first time in North America, these researchers will determine exposure levels by postal code, considering factors such as:

• urban air quality;
• population density;
• traffic data;
• emission sources, such as local industry and wood smoke;
• prevailing weather conditions; and
• different elevations.

Information is then sorted by postal code in a computerized database so that health impacts in each local area can be matched with air quality conditions in the same local area over a pre-set study period.

Once this database of information on each postal code has been established, researchers will assess the impacts of air pollution on young children and births to women living in the study area. Birth outcomes and the health of children will be tracked using the BC Linked Health Database. Ideally, the results of this study will show if there is a relationship between air pollution and adverse birth outcomes or respiratory disease in children.

To obtain these results, Health Canada is funding four specific health impact research projects under the Georgia Basin/Puget Sound International Airshed Strategy:

1. Establishment of a Childhood Respiratory Disease Cohort using the BC Linked Health Database
2. Analysis of Birth Outcomes in the Greater Vancouver Regional District using the BC Perinatal Database Registry and the BC Linked Health Database
3. Consolidation and Evaluation of Existing Geographic Data for the Georgia Basin/Puget Sound International Airshed
4. Enhanced Assessment of Exposure to Traffic and Wood Smoke and Incorporation of Meteorology

Establishment of a Childhood Respiratory Disease Cohort using the BC Linked Health Database

Respiratory disease in children has been linked to air pollution exposure in numerous settings. Motor vehicle and wood smoke emissions are of particular concern in the Georgia Basin/Puget Sound airshed region.

This project will follow children's health from before they are born (called a birth cohort) to look at the incidence of childhood respiratory disorders relative to air pollution exposure in the Georgia Basin Airshed. Ultimately, this project will examine the ongoing relationship between changing levels of air pollutants (due to air quality management strategies and changes in emissions) and child respiratory problems.

The cohort will include approximately 90,000 children born in the Georgia Basin over a three-year period beginning in 1999. Separate analyses will be conducted to assess respiratory health outcomes among First Nation children, who may be at increased risk. Analyses will focus on asthma and bronchiolitis, and other common respiratory concerns will be considered. The research on bronchiolitis, which has rarely been studied in relation to air pollution, will complement work being done by the University of Washington.

Analysis of Birth Outcomes in the Greater Vancouver Regional District using the BC Perinatal Database Registry and the BC Linked Health Database

Several recent studies have provided evidence of an association between adverse birth outcomes and air pollution, particularly traffic-related air pollution. These studies suggest that birth outcomes may be an especially sensitive indicator of the health impacts of air pollution. This study will therefore examine the relationship between adverse birth outcomes and exposure to air pollutants in the Greater Vancouver Regional District.

The cohort used will be a subset (approximately 60,000 births in this district) of the cohort established for Project 1. This project will evaluate low birth weight (<2500 grams), pre-term birth (<37 weeks), and intrauterine growth retardation (IUGR).

Initial analysis will incorporate exposure estimates based on ambient air pollution measurements and individual estimates of exposure based on measures of traffic proximity and a traffic-based exposure model. Exposure will be assessed using models based on the postal code of the mother's residential address during pregnancy. This model combines GIS-based traffic and land-use variables with ambient monitoring data to develop a continuous spatial surface of long-term average ambient air pollutant concentrations to adjust exposures for specific gestational periods.

Consolidation and Evaluation of Existing Geographic Data for the Georgia Basin/Puget Sound International Airshed

A broad range of information on air quality, pollution sources, geographical features and socioeconomic characteristics has been collected throughout the Georgia Basin/Puget Sound airshed by different levels of Canadian and American governments, working groups, researchers and consultants.

This project will bring existing data together as a single geo-database for the entire
air basin and adjacent marine environments. At present, there is no synthesized description of data available for human health and air pollution research in this region, nor is there a coordinated data collectin strategy.

The development of this geo-database is critical to the success of the cohort studies in Project 1 and Project 2. It will provide more refined and accurate estimates of exposure levels of the populations in the area, and reduce the error of risk assessment. The database will also identify data gaps and provide direction for future data collection efforts as well as become a significant resource for future projects in both the Canadian and American areas of the basin region.

Enhanced Assessment of Exposure to Traffic and Wood Smoke and Incorporation of Meteorology

This project will build on and extend the consolidated geo-database described in Project 3 with enhanced measurements and analysis focussed on local traffic, wood smoke and meteorology. More specifically, it will:

• use existing household wood smoke surveys to document and model the spatial distribution of wood smoke emissions;
• use urban road network databases to model local traffic emission exposures across the region;
• assess the feasibility of integrating meteorological and topographical modelling approaches to improve the above exposure assessments;
• validate modelled ambient wood smoke and traffic emissions with air quality measurements; and
• integrate modeled and validated wood smoke and traffic emissions with the data collected in Project 3 for a multi-scale, multi-pollutant geographic analysis of the Greater Vancouver Regional District.

Initially, this project will focus on the Greater Vancouver Regional District to develop a prototype for data collection, exposure assessment and health studies across the entire Georgia Basin/Puget Sound airshed in future research.

Ultimately, it will lead to the development of an exposure assessment methodology for traffic emissions and wood smoke that can be applied not only to communities but also to individuals and smaller areas, such as urban neighbourhoods.