Identifying potential exposure reduction priorities using regional rankings based on emissions of known and suspected carcinogens to outdoor air in Canada.

Eleanor M Setton,Steeve Deschenes,Paul A Demers,C Peter Keller,Basil Veerman,Roz Cheasley,Karla Poplawski,Anders Erickson

doi:10.1186/s12940-015-0055-2

Abstract

BackgroundEmissions inventories aid in understanding the sources of hazardous air pollutants and how these vary regionally, supporting targeted reduction actions. Integrating information on the relative toxicity of emitted pollutants with respect to cancer in humans helps to further refine reduction actions or recommendations, but few national programs exist in North America that use emissions estimates in this way. The CAREX Canada Emissions Mapping Project provides key regional indicators of emissions (total annual and total annual toxic equivalent, circa 2011) of 21 selected known and suspected carcinogens.MethodsThe indicators were calculated from industrial emissions reported to the National Pollutant Release Inventory (NPRI) and estimates of emissions from transportation (airports, trains, and car and truck traffic) and residential heating (oil, gas and wood), in conjunction with human toxicity potential factors. We also include substance-specific annual emissions in toxic equivalent kilograms and annual emissions in kilograms, to allow for ranking substances within any region.ResultsFor provinces and territories in Canada, the indicators suggest the top five substances contributing to the total toxic equivalent emissions in any region could be prioritized for further investigation. Residents of Quebec and New Brunswick may be more at risk of exposure to industrial emissions than those in other regions, suggesting that a more detailed study of exposure to industrial emissions in these provinces is warranted. Residential wood smoke may be an important emission to control, particularly in the north and eastern regions of Canada. Residential oil and gas heating, along with rail emissions contribute little to regional emissions and therefore may not be an immediate regional priority.ConclusionsThe developed indicators support the identification of pollutants and sources for additional investigation when planning exposure reduction actions among Canadian provinces and territories, but have important limitations similar to other emissions inventory-based tools. Additional research is required to evaluate how the Emissions Mapping Project is used by different groups and organizations with respect to informing actions aimed at reducing Canadians’ potential exposure to harmful air pollutants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-015-0055-2) contains supplementary material, which is available to authorized users.

Highlights

Emissions inventories aid in understanding the sources of hazardous air pollutants and how these vary regionally, supporting targeted reduction actions
We describe the development and implementation of the CAREX Emissions Mapping Project (EMP) in Canada, a Google Earth-based data set that includes indicators based on emissions of 21 known and suspected carcinogens to air, as reported to the National Pollutant Release Inventory (NPRI) and from our own estimates of emissions from transportation and residential heating, circa 2011 [19]
Total toxic equivalent kilograms (TEQ) was calculated from data reported to the National Pollutant Release Inventory (NPRI) and our own estimates of emissions from transportation and residential heating, in conjunction with human toxicity potential factors developed by EG Hertwich et al [20]

Summary

Introduction

Emissions inventories aid in understanding the sources of hazardous air pollutants and how these vary regionally, supporting targeted reduction actions. In conjunction with measuring pollutant levels in outdoor air, understanding the sources of pollutants, their relative and cumulative contribution to potential health impacts, and how these vary regionally is key to developing targeted emissions reduction strategies [5]. Emissions inventories are commonly used to estimate the relative contributions of various sources of pollutants in one or more geographic areas. In Canada, the federal government maintains the National Pollutant Release Inventory (NPRI) and requires industrial and commercial point sources above a certain size to report annual releases and transfers to air, land and water [6]. National emissions inventories that include point, line and area sources are prepared by the federal government [7], and more detailed regional or local emissions inventories are sometimes prepared by provincial and municipal governments [8, 9]

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