Advances in Near Reference Method Ambient Monitoring Technology - What, Why, Where?

Abstract Description: Through collaboration, Aeroqual and WSP have successfully incorporated near-reference monitoring on more than 40 projects across North America to provide local, defensible air quality data that has been used to support decision-making, establish baseline air quality, and protect community air quality with fenceline installations at major infrastructure and remediation projects.

Near-reference monitoring achieves defensible data quality, gaining broader acceptance as an alternative to costly reference method installations. Aeroqual’s near-reference technology and innovations use optical particle sensors, photoionization detectors (PIDs), heated metal oxide semiconductor (HMOS) sensors, and electrochemical gas sensors to measure contaminant concentrations. Instrument performance will be illustrated by the findings of evaluations carried out by WSP at project sites and those done in collaboration with regulators in the US and Canada, with R2 values of over 0.98 in the lab and over 0.8 in the field.

The near-reference methods have addressed barriers to continuous monitoring at remote sites, with remote calibration to maintain data quality without physically attending to the monitor. The instruments have also been adapted to operate under extreme conditions at some northern installations, where temperatures reach -40°F in the winter.

Client access to real-time analytics on a shared dashboard has provided transparency and allowed for informed discussions with stakeholders and residents about dust and air quality. This access to real-time data also allows for optimization of dust and air emissions management, which is particularly important at sites where water conservation must be balanced with the application of water as the primary means of dust control.

WSP has mobilized over 150 near-reference monitors, and this experience will be shared with brief case studies that demonstrate how these near-reference methods achieved the objectives of fenceline and remote baseline monitoring programs and some of the challenges faced.