Opportunities for using spatial property assessment data in air pollution exposure assessments

BACKGROUND: Many epidemiological studies examining the relationships between adverse health outcomes and exposure to air pollutants use ambient air pollution measurements as a proxy for personal exposure levels. When pollution levels vary at neighbourhood levels, using ambient pollution data from sparsely located fixed monitors may inadequately capture the spatial variation in ambient pollution. A major constraint to moving toward exposure assessments and epidemiological studies of air pollution at a neighbourhood level is the lack of readily available data at appropriate spatial resolutions. Spatial property assessment data are widely available in North America and may provide an opportunity for developing neighbourhood level air pollution exposure assessments. RESULTS: This paper provides a detailed description of spatial property assessment data available in the Pacific Northwest of Canada and the United States, and provides examples of potential applications of spatial property assessment data for improving air pollution exposure assessment at the neighbourhood scale, including: (1) creating variables for use in land use regression modelling of neighbourhood levels of ambient air pollution; (2) enhancing wood smoke exposure estimates by mapping fireplace locations; and (3) using data available on individual building characteristics to produce a regional air pollution infiltration model. CONCLUSION: Spatial property assessment data are an extremely detailed data source at a fine spatial resolution, and therefore a source of information that could improve the quality and spatial resolution of current air pollution exposure assessments

Spatial variations in estimated chronic exposure to traffic-related air pollution in working populations: A simulation

<p>Abstract</p> <p>Background</p> <p>Chronic exposure to traffic-related air pollution is associated with a variety of health impacts in adults and recent studies show that exposure varies spatially, with some residents in a community more exposed than others. A spatial exposure simulation model (SESM) which incorporates six microenvironments (<it>home indoor</it>, <it>work indoor</it>, <it>other indoor</it>, <it>outdoor</it>, <it>in-vehicle to work </it>and <it>in-vehicle other</it>) is described and used to explore spatial variability in estimates of exposure to traffic-related nitrogen dioxide (not including indoor sources) for working people. The study models spatial variability in estimated exposure aggregated at the census tracts level for 382 census tracts in the Greater Vancouver Regional District of British Columbia, Canada. Summary statistics relating to the distributions of the estimated exposures are compared visually through mapping. Observed variations are explored through analyses of model inputs.</p> <p>Results</p> <p>Two sources of spatial variability in exposure to traffic-related nitrogen dioxide were identified. Median estimates of total exposure ranged from 8 μg/m³to 35 μg/m³of annual average hourly NO₂for workers in different census tracts in the study area. Exposure estimates are highest where ambient pollution levels are highest. This reflects the regional gradient of pollution in the study area and the relatively high percentage of time spent at home locations. However, for workers within the same census tract, variations were observed in the partial exposure estimates associated with time spent outside the residential census tract. Simulation modeling shows that some workers may have exposures 1.3 times higher than other workers residing in the same census tract because of time spent away from the residential census tract, and that time spent in work census tracts contributes most to the differences in exposure. Exposure estimates associated with the activity of commuting by vehicle to work were negligible, based on the relatively short amount of time spent in this microenvironment compared to other locations. We recognize that this may not be the case for pollutants other than NO_2.These results represent the first time spatially disaggregated variations in exposure to traffic-related air pollution within a community have been estimated and reported.</p> <p>Conclusion</p> <p>The results suggest that while time spent in the <it>home indoor </it>microenvironment contributes most to between-census tract variation in estimates of annual average exposures to traffic-related NO₂, time spent in the <it>work indoor </it>microenvironment contributes most to within-census tract variation, and time spent in transit by vehicle makes a negligible contribution. The SESM has potential as a policy evaluation tool, given input data that reflect changes in pollution levels or work flow patterns due to traffic demand management and land use development policy.</p

The Canadian Urban Environmental Health Research Consortium (CANUE): a national data linkage initiative

Introduction Health and environmental exposure databases are generally siloed in different research institutions across Canada and integrating them for environmental health research is a considerable challenge. Facilitating the linkage of these databases is essential to provide new analytical opportunities and help create efficiencies for research on environmental determinants of health. Objectives and Approach CANUE is a Canadian Institutes of Health Research-funded platform for supporting environmental health research. CANUE collates and generates standardized environmental data on air and noise pollution, land use, green/natural spaces, climate change/extreme weather, and socioeconomic conditions for every postal code in Canada and makes them freely available to researchers. Systems and procedures are being developed by CANUE to facilitate the sharing and integration of these extensive geospatial exposures with existing observational cohorts and administrative health databases across Canada. This linkage will enable investigators to test hypotheses on the interdependent associations of environmental features with health impacts or benefits. Results CANUE now hosts a dozen national exposure databases and related metadata files, and actively adds new regional and national datasets. Streamlined processes for data sharing have been developed to facilitate easy merging with health data. Substantial consultation has also taken place with a wide range of health data holders to establish appropriate processes for receiving and managing environmental data, with particular focus on addressing challenges presented by differing ethics, consent and confidentiality requirements. These processes help accelerate the research process by making analysis-ready data available to investigators, create opportunities to study how multiple environmental factors are linked to a wide range of health outcomes, and generally increase the use of health and population databases for environmental health research. Conclusion/Implications The CANUE collaborative model illustrates how the production of policy-relevant evidence can be advanced through better coordination among environmental health researchers and linkage with health databases. CANUE is improving the scientific potential and cost-effectiveness of research in environmental epidemiology through streamlining linkage and access to standardized exposure datasets

Probabilistic estimates of variability in exposure to traffic-related air pollution in the Greater Vancouver Regional District - a spatial perspective

A probabilistic spatial exposure simulation model (SESM) was designed to investigate the effect of time spent at work and commuting on estimates of chronic exposure to traffic-related air pollution in large populations. The model produces distributions of exposure estimates in six microenvironments (home indoor, work indoor, other indoor, outdoor, transit to work and transit other) for workers and non-workers, using randomly sampled time-activity patterns from the Canadian Human Activity Pattern Survey and work flow data from Statistics Canada. The SESM incorporates geographic detail through the use of property assessment data, shortest route analysis, and the use of a geographic information system (GIS) to develop pollution concentration distributions. The SESM was implemented and tested using data for 382 census tracts in the Greater Vancouver Regional District of British Columbia. Simulation results were found to be relatively insensitive to the choice of distance used to represent the typical range of non-work related trips; the use of a simple annual average pollution estimate versus a time-stratified annual average; and the use of different indoor/outdoor ratios representing the infiltration of ambient pollution into indoor locations. Substantial sensitivity was observed based on the use of different methods for producing spatial estimates of ambient air pollution. The SESM was used to explore variability in annual total exposure of workers to traffic-related nitrogen dioxide (NO2). Total exposure ranged from 8 μg/m3 to 35 μg/m3 of iv annual average hourly NO2 and was highest where ambient pollution levels are highest, reflecting the regional gradient of pollution in the study area and the relatively high percentage of time spent at home locations. Within census tract variation was observed in the partial exposure estimates associated with time spent at work locations, particularly in suburban areas where longer commuting distances are more prevalent. In these areas, some workers may have exposures 1.3 times higher than other workers residing in the same census tract. Exposures to NO2 associated with the activity of commuting to work were negligible. No statistically significant difference in total exposure estimates was found between female and male commuters, although there were small but observable differences at the upper end of the exposure distributions associated specifically with the work indoor microenvironment. These differences were highest in suburban areas (up to 3 μg/m3 of annual hourly average NO2 higher for female commuters, in relation to 99th percentile total exposures levels of approximately 37 μg/m3), illustrating the impact of systematically different work locations for female compared to male commuters in these same census tracts. Simulated exposures for workers, non-workers, and a base scenario where all time is spent at the residence only were compared. Statistically significant differences were found in the exposure distributions for workers versus non-workers, workers versus residence only, and non-workers versus residence only. Differences in exposure within census tracts were highest at the 10th and 90th percentiles, on the order of -5.4 to +6.5 μg/m3 of annual average hourly NO2 respectively for workers compared to non-workers, in relation to exposure estimates between 10 and 40 μg/m3 of annual average hourly NO2 on average

Lifetime excess cancer risk due to carcinogens in food and beverages: Urban versus rural differences in Canada

OBJECTIVES: To explore differences in urban versus rural lifetime excess risk of cancer from five specific contaminants found in food and beverages. METHODS: Probable contaminant intake is estimated using Monte Carlo simulations of contaminant concentrations in combination with dietary patterns. Contaminant concentrations for arsenic, benzene, lead, polychlorinated biphenyls (PCBs) and tetrachloroethylene (PERC) were derived from government dietary studies. The dietary patterns of 34 944 Canadians from 10 provinces were available from Health Canada’s Canadian Community Health Survey, Cycle 2.2, Nutrition (2004). Associated lifetime excess cancer risk (LECR) was subsequently calculated from the results of the simulations. RESULTS: In the calculation of LECR from food and beverages for the five selected substances, two (lead and PERC) were shown to have excess risk below 10 per million; whereas for the remaining three (arsenic, benzene and PCBs), it was shown that at least 50% of the population were above 10 per million excess cancers. Arsenic residues, ingested via rice and rice cereal, registered the greatest disparity between urban and rural intake, with LECR per million levels well above 1000 per million at the upper bound. The majority of PCBs ingestion comes from meat, with values slightly higher for urban populations and LECR per million estimates between 50 and 400. Drinking water is the primary contributor of benzene intake in both urban and rural populations, with LECR per million estimates of 35 extra cancers in the top 1% of sampled population. CONCLUSION: Overall, there are few disparities between urban and rural lifetime excess cancer risk from contaminants found in food and beverages. Estimates could be improved with more complete Canadian dietary intake and concentration data in support of detailed exposure assessments in estimating LECR.FacultyReviewe

Cancer and the Environment projects with four First Nations organizations: working together to address concerns about carcinogens in the environment

Abstract Setting For First Nations people, human health and well-being are interconnected with a healthy environment. First Nations organizations commonly raise concerns regarding carcinogens in the environment; however, few case studies are available as guidance for working in a participatory and respectful way to help assess and address these concerns. Intervention Through four community-led pilot projects executed over two years, we collaborated with 15 participants from four First Nations organizations across four provinces to identify concerns related to environmental carcinogens and to address those concerns through an integrated knowledge translation (KT) approach. We co-developed and implemented strategic KT plans for each pilot project, and conducted evaluation surveys and interviews with participants at multiple time points to assess process, progress, barriers and facilitators, and impact. Outcomes The activities and outputs of the pilot projects are available at www.carexcanada.ca. Participants identified 18 concerns, and we co-developed 24 knowledge products. Tailored fact sheets for communities and briefing notes for leadership were deemed most useful; interactive maps were deemed less useful. Evaluation indicated that the collaborative projects were effective in addressing the concerns raised regarding exposures to carcinogens. Implications The participant-led approach and multi-year funding to support capacity enhancement and face-to-face engagement were facilitators to project success. However, participants did face important barriers to collaborate which should be considered in future projects of this kind: the most important being a lack of resources (people and time), given competing and often more urgent priorities. </jats:sec