High-purity quartz (SiO₂) microfiber filters are used for air sampling in acidic gases, stacks, flues and aerosols, particularly at high temperatures up to 500° C and in PM-10 testing. Because of the low level of alkaline earth metals, ''artifact'' products of sulfates and nitrates (from SO₂ and NO₂) are virtually eliminated. QM-A, sequentially numbered according to EPA standards, is suitable for most applications. Here you can find the certificate: https://www.cytivalifesciences.com/en/de/support/quality/certificatesMeer tonenMinder tonen