PM10/PM2.5/PM1 Data from a Trichotomous Sampler

As part of an effort to determine whether 1 μm or 2.5 μam is the better choice for a new fine particulate matter standard, Professor Virgil A. Marple of the University of Minnesota developed a high volume trichotomous (PM 10 /PM 2.5 /PM 1 ) sampler. Two of these samplers were used to obtain particulate matter (PM) samples at a site located in Phoenix, Arizona, from May 1995 through October 1995. All filter samples were analyzed for mass concentrations and a few for elemental and chemical compositions. Relative fractions were determined for PM 10 , PM 2.5 , PM 1 , PM 2.5-10 , and PM 1-2.5. Calculations were made to evaluate how coarse and fine mode aerosol contributed to the intermediate size range. Results indicated that most of the PM 10 in Phoenix was coarse mode PM (windblown dust), which was also a primary contributor to PM 25 .