Notes
Puget Sound Clean Air Agency (PSCAA) Monitoring Team October 2024 presentation on ongoing ultrafine particle (UFP) monitoring. Covers key acronyms and facts: UFP defined as particles less than 100 nm or 0.1 microns, particle number concentration (PNC), SMPS (Scanning Mobility Particle Size Spectrometer), and the fact that UFPs account for more than 80% of PNC. Notes UFPs are not a criteria pollutant under current air quality standards, with no reference methodology or SOP. References WHO 2021 good practice statement on UFP monitoring, including recommended PNC thresholds (low PNC < 1,000 particles/cm3 24-hour mean; high PNC > 10,000 particles/cm3 24-hour mean or 20,000 particles/cm3 1-hour). Includes size comparison of PM10, PM2.5, and ultrafine (0.1 µm) particles.