Abstract: Methods and apparatus for the continuous monitoring of ambient particulate mass in a gas sample encompassing the monitoring of PM.sub.10, (particulate matter greater than 10 .mu.m) and coarse particles (2.5 to 10 .mu.m), the determination of the size distribution of particles, the determination of particle density and the determination of particle-bound water, utilizing such laboratory equipment as an inertial impactor, a virtual impactor, diffusion dryer(s), HEPA filter(s), particulate matter collector(s), and pressure transducer(s).

Abstract: A method for continuously measuring particulate nitrate in a gas sample, comprising the steps of passing the gas sample through an inertial impactor with a 50% cut off at 2.5 microns, removing ambient pollutant gases from the gas with diffusion denuders, passing the gas through a first path so as to contact the gas with a coated filter so as to convert particulate nitrate to nitric acid vapor or passing the gas through a second path so as to contact the gas with coated filters to trap particulate nitrate and ammonia, and measuring nitric acid vapor and residual ambient pollutant gases produced from the first path and residual ambient pollutant gases produced from the second path with a chemiluminescent monitor, the difference in the signal produced from the gases from the two paths being a measurement of the particulate nitrate in the gas sample.