Over the last decade a large number of measurement methods for fine, coarse and ultrafine particles have been developed to characterize ambient PM2.5 as well as personal PM2.5 exposures. These new devices will enable us to improve our understanding of factors affecting human exposure to particulate and gaseous air pollutants. A brief description and commentary on these methods is presented. Broadly, these techniques can be divided into two categories: integrated methods that are mostly filter-based, and continuous methods which are based on the measurement of physical properties of particles. In addition, we also review how our personal multipollutant sampler has been used in field studies in various locations in the United States of America.