Until recently, it was believed that the toxicological effects of air polluting particles could be eliminated by decreasing the mass of particles in the air. Recent epidemiological studies have proved this to be untrue. It may be that very small particles present in the air have more significance for toxic effects than the total mass of particles present. Studies in partical toxicology have undergone significant changes over the past 5 years, and Particulate Matter provides an up-to-date and comprehensive account of current knowledge in this area. It reviews physical and chemical properties...