High-purity quartz (SiO2) microfiber Filters are used for air sampling in acidic gases, stacks, blues and aerosols, particularly at high temperatures up to 5 degrees C and in PM-1 testing. Because of the low level of alkaline earth metals, "artifact" products of sulfates and nitrates (from SO2 and NO2) are virtually unlimited. QM-A, sequentially numbered according to EPA standards, is suitable for most applications.
