Applications of Satellite Remote Sensing to Urban Air-Quality Monitoring: Status and Potential Solutions to Canada

Abstract. Urban air quality has traditionally been monitored with networks of ground monitoring stations and the use of models that evaluate emissions and predict changes in air quality at discrete points. The increasing availability of earth observing satellite systems and onboard imaging sensors together with advances in digital image processing techniques provide a new avenue to monitor urban air quality at a citywide and regional scale. We begin with the investigations on existing spaceborne imaging sensors and with some examples of the satellite image data in urban air quality monitoring. We then examine four major satellite-based approaches: measuring the thickness of aerosol in the atmosphere, satellite image visual inspection, black particle measurement, and land-use/land-cover change analysis. The focus of the paper is on the first approach, through an in-depth analysis of various case studies. Briefly described is a framework for using multisensor, multitemporal, and multispectral satellite images to better understand the cause-and-effect relationships between urbanization and trends in climatology and air quality. We conclude with a look at promising new approaches and development. This work is primarily based on an assessment conducted at the CFI Virtual Environment Laboratory at Ryerson University on the potential use of satellite data to monitor urban air quality in the City of Toronto and within the Greater Toronto Area, Ontario