Figure 1From: Particulate matter and atherosclerosis: role of particle size, composition and oxidative stress Idealized particle size distribution that might be observed in traffic. Particles from different sizes are generated by four modes: nucleation, aitken, accumulation and coarse mode. Also shown are the major formation and growth mechanisms of the four modes of ambient particles. V = volume, Dp = particle diameter. Source: U.S. EPA [8].Back to article page