From Earth to Space, Lasers Take on Pollution

Stephen E. Moody, Orca Photonic Systems Inc.

Recent advances in solid-state-laser and nonlinear optics technology are increasing the performance, versatility and reliability of the lasers that we can design into sensing systems.

The monitoring and management of air quality is of direct concern to everyone living in the industrialized nations of the world. The economic and social activities of a modern society lead to emissions from a multitude of sources that affect air quality. These emissions take the form of gases and particulates, both of which have well-documented effects on human, animal and plant health when levels are too high.

Air quality is a distributed problem. There are numerous sources of polluting emissions, especially when cars are entered into the equation. Once entrained by the atmosphere, pollutants move and are often chemically modified as part of the natural atmospheric circulation process. As a result, the relationship between source and effect is not always easy to establish.

Point measurements of emissions at the source, which are the primary basis of our current regulatory fabric for air quality, are not enough to fully characterize air quality in a particular region. Because these measurements provide no information about transport or atmospheric chemistry, they can't by themselves predict the air quality that will actually result from a given set of sources.

To surmount these limitations, various kinds of remote sensing have an important role to play. Remote sensing's ability to map the atmosphere over broad areas of space and time allows us to include the effects of transport and thereby to strike a better balance between cost and benefit as we make important decisions about the management of air quality.