title: Air toxics in Canada measured by the National Air Pollution Surveillance (NAPS) program and their relation to ambient air quality guidelines.
abstract: This study reports ambient concentrations of 63 air toxics that were measured in Canada by the National Air Pollution Surveillance (NAPS) program over the period 2009-2013. Measured concentrations are compared with ambient air quality guidelines from Canadian jurisdictions, and compounds that exceeded guidelines are identified and discussed. Although this study does not assess risk or cumulative effects, air toxics that approached guidelines are also identified so that their potential contribution to ambient air toxics pollution can be considered. Eleven air toxics exceeded at least one guideline, and an additional 16 approached guidelines during the study period. Four compounds were measured using methods whose detection limits exceeded a guideline value, three of which could not be compared with guidelines, since they were not detected in any samples. The assessment of several metal(loid) concentrations is tentative, since they were measured only in fine particulate matter (PM) but compared with guidelines based on coarse or total PM. Improvements to sampling and analysis techniques for the latter compounds as well as for those whose methods are subject to known uncertainties would improve confidence in reported concentrations and their relation to applicable guidelines. Analysis of sampling strategies for all compounds found to exceed or approach guidelines would contribute to ensuring that their spatiotemporal coverage is adequate. Examination of the air toxics not measured by NAPS but having guidelines in Canadian jurisdictions or being included in other programs such as the U.S. National-Scale Air Toxics Assessment (NATA) would contribute to ensuring that the full suite of pollutants relevant to ambient air quality in Canada is subject to adequate study. The results of this study can be applied to evaluating the effectiveness of toxic substances management in Canada.
  
  
  CONCLUSIONS
  Recent measurements of 63 air toxics in Canada by the National Air Pollution Surveillance (NAPS) program showed that 11 compounds exceeded daily or annual ambient air quality guidelines and that an additional 16 compounds approached such guidelines within an order of magnitude. The results of this study can be applied to evaluating the effectiveness of toxic substances management in Canada and to identifying compounds that merit further investigation.
authors.affiliation: a Air Quality Processes Research Section , Air Quality Research Division, Environment Canada , Toronto , Ontario , Canada.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Galarneau
authors.affiliation: b Analysis and Air Quality Section, Air Quality Research Division , Environment Canada , Ontario , Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Wang
authors.affiliation: b Analysis and Air Quality Section, Air Quality Research Division , Environment Canada , Ontario , Canada.
authors.forename: Ewa
authors.initials: E
authors.lastname: Dabek-Zlotorzynska
authors.affiliation: b Analysis and Air Quality Section, Air Quality Research Division , Environment Canada , Ontario , Canada.
authors.forename: May
authors.initials: M
authors.lastname: Siu
authors.affiliation: b Analysis and Air Quality Section, Air Quality Research Division , Environment Canada , Ontario , Canada.
authors.forename: Valbona
authors.initials: V
authors.lastname: Celo
authors.affiliation: b Analysis and Air Quality Section, Air Quality Research Division , Environment Canada , Ontario , Canada.
authors.forename: Mylaine
authors.initials: M
authors.lastname: Tardif
authors.affiliation: b Analysis and Air Quality Section, Air Quality Research Division , Environment Canada , Ontario , Canada.
authors.forename: David
authors.initials: D
authors.lastname: Harnish
authors.affiliation: b Analysis and Air Quality Section, Air Quality Research Division , Environment Canada , Ontario , Canada.
authors.forename: Ying
authors.initials: Y
authors.lastname: Jiang
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000592:standards*; D000397:Air Pollution / Q000032:analysis*; D002170:Canada; D004784:Environmental Monitoring / Q000379:methods*; D008670:Metals / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis; D055549:Volatile Organic Compounds / Q000032:analysis
chemical_list: D000393:Air Pollutants; D008670:Metals; D052638:Particulate Matter; D055549:Volatile Organic Compounds