Windsor, Ontario Exposure Assessment Study: Design and Methods Validation of Personal, Indoor, and Outdoor Air Pollution Monitoring

ABSTRACT

The Windsor, Ontario Exposure Assessment Study evaluated the contribution of ambient air pollutants to personal and indoor exposures of adults and asthmatic children living in Windsor, Ontario, Canada. In addition, the role of personal, indoor, and outdoor air pollution exposures upon asthmatic children's respiratory health was assessed. Several active and passive sampling methods were applied, or adapted, for personal, indoor, and outdoor residential monitoring of nitrogen dioxide, volatile organic compounds, particulate matter (PM; PM ≤ 2.5 μm [PM_2.5] and ≤ 10 μm [PM₁₀] in aerodynamic diameter),elemental carbon, ultrafine particles, ozone, air exchange rates, allergens in settled dust, and particulate-associated metals. Participants completed five consecutive days of monitoring during the winter and summer of 2005 and 2006. During 2006, in addition to undertaking the air pollution measurements, asthmatic children completed respiratory health measurements (including peak flow meter tests and exhaled breath condensate) and tracked respiratory symptoms in a diary. Extensive quality assurance and quality control steps were implemented, including the collocation of instruments at the National Air Pollution Surveillance site operated by Environment Canada and at the Michigan Department of Environmental Quality site in Allen Park, Detroit, MI. During field sampling, duplicate and blank samples were also completed and these data are reported. In total, 50 adults and 51 asthmatic children were recruited to participate, resulting in 922 participant days of data. When comparing the methods used in the study with standard reference methods, field blanks were low and bias was acceptable, with most methods being within 20% of reference methods. Duplicates were typically within less than 10% of each other, indicating that study results can be used with confidence. This paper covers study design, recruitment, methodology, time activity diary, surveys, and quality assurance and control results for the different methods used.

IMPLICATIONS

It is important to obtain data to identify any factors that can influence the relationships among personal, indoor, and outdoor concentrations for a range of air pollutants. Ensuring that the methods used are valid and comparable to reference methods used in typical air pollution, monitoring is crucial for data to be of use to regulators. These exposure data can then be used to develop risk management policies that reduce personal and indoor exposures to air pollutants.

ACKNOWLEDGMENTS

The participants and their families are gratefully thanked for their contributions to these 2 yr of data collection; without them, none of this research would have been possible. The careful field work undertaken by the numerous field technicians from Health Canada and the University of Windsor is appreciated. The authors would like to acknowledge contributions from Dr. Paul Villeneuve (Health Canada) for the power calculation; Alice Grgicak-Mannion (Great Lakes Institute for Environmental Research, University of Windsor) for the map of residential locations; Mark Davey (University of Washington), Steve Ferguson, and Dr. Mike Wolfson (Harvard School of Public Health) for their guidance on methods and laboratory analyses; Sandy Benetti of Environment Canada for her help in the initial coordination of the laboratory activities and sample analyses; Don Fugler of the Canadian Mortgage and Housing Corporation and Dr. Russell Dietz of Brookhaven National Laboratory for their support with AER measurements; Environment Canada and MDEQ for permitting the authors to locate instruments at the College Road and Allen Park sites and access to their data for the method comparisons; and Dr. Markey Johnson and Dr. Scott Weichenthal from Health Canada for conducting the internal review. BAQS provided funding through Health Canada. Although this work was reviewed by EPA and approved for publication, it may not necessarily reflect official agency policy.