Signal Processing Plays a Key Role in Environmental Research Projects: Keeping People and Ecosystems Alive and Healthy Is Perhaps the 21st Century's Biggest Challenge

Despite the impressive technological strides made over the years, human lives still depend very much on the natural environment. Fortunately, technology can now be used to help address critical environmental concerns in air quality, soil condition, and weather events. In all of these areas and many others, signal processing is supporting the ability to provide immediate and long-term observations and insights.

Efficient air-quality monitoring

It’s generally accepted that the efficient monitoring of airborne particulate matter (PM), particularly particles with an aerodynamic diameter measuring less than 2.5 μm (PM2.5), is an important step toward sustaining and improving public health.

Acknowledging this fact, researchers at the Max Planck Institute for the Science of Light have developed a novel way to continuously monitor a local environment for both the size and optical properties of individual airborne particles. The technique utilizes optical forces to automatically capture airborne particles and then propel them into a hollow-core fiber where they can be studied and counted, providing a potentially better way to monitor air pollution levels.

On-the-fly particle metrology uses both advanced optics and signal processing to continuously monitor the size and refractive index of individual airborne particles in an open atmosphere, says research team leader Shangran Xie (Figure 1). “It can overcome several limitations of … existing methods, offering the ability of simultaneous measurement of particle size and refractive index, which can assist in identifying particle material, real-time particle metrology, highly reproducible results, and unlimited device lifetime,” he explains.