Michael Kleeman, Ph.D.

Professor Michael Kleeman's research is focused on the study of urban and regional air quality problems with an emphasis on the size and composition of atmospheric particles and gas-to-particle conversion processes. These issues are important because research has found that airborne particles with diameters less than 2.5 microns cause adverse health effects. The size and composition of particles found in the atmosphere also determines much of the visibility reduction observed in large cities.

The experimental component of his research involves the measurement of the size and composition of particles when they are released to the atmosphere and after they have been transformed by physical and chemical processing.

This detailed information is then used in mechanistic air quality modeling calculations that track the evolution of particles in the atmosphere after they have been released from the source. By following these particles separately, it is possible to calculate how different emissions sources influence the size and composition of particles at down-wind receptor sites. Ultimately, this makes it possible to calculate the effect that different sources have on visibility and human health.

Detailed calculations such as those described above require significant computational resources. Today's supercomputers have grown to meet these challenges but at a large price. To overcome this obstacle, his research group uses clustered workstations and the Linux operating system to create a distributed memory parallel computer ("beowulf" system). This platform provides a powerful and flexible computing environment suitable for large air quality modeling calculations.

The computer cluster maintained by the Kleeman research group for air quality modeling has 400 nodes and is one of the largest parallel computers within the University of California system that is operated by a single research group.