Aerosol Mass Spectrometers Do they keep their promise
- Slides: 6
Aerosol Mass Spectrometers: Do they keep their promise? Rainer Vogt Ford Forschungszentrum Aachen Gmb. H Germany Research & Advanced Engineering
The promise: ØProvide time resolved size distribution and chemical composition of ambient aerosol in the 10 nm to 10 mm size range Research & Advanced Engineering
What have we learnt? What can we learn? (1) • Can aerosol mass spectrometry detect atmospheric aerosol processes? Ø Yes! Research & Advanced Engineering (Gard et al, Science 1998)
What can/have we learnt? (2) • Health discussion raises question of relevance of particle number besides PM mass. Can single particle MS do number apportionment to specific sources? Daily variation of major particle classes (Tan et al. , ES&T 2002) 0. 5 µm diameter particles at an Autobahn & rural site (Vogt et al. , Aerosol Science 2003) Ø Yes, but attribution depends on instrument and scientist. Ø Issue with detection efficiency Research & Advanced Engineering carbon cotaining particles, (Lake et al, ES&T 2003)
Issues with Aerosol Mass Spectrometers • Detection efficiency varies by particle size from 10 -2 to 10 -6 (for Laserionization) • Ionization efficiency is species dependent (Single Particle MS) • Quantitative analysis only for volatile (non-refractory) PM (AMS) • Labor intense operation and data analysis: limited to special campaigns Research & Advanced Engineering
The future? • Aerosol mass spectrometers are not the universal aerosol analyser • Use for specific problems: ØChemical composition of 10 -100 nm (ultrafine) volatile particles ØState of aerosol mixing, atmospheric chemical processing ØSource attribution by aerosol number: link to epidemiology/health programs Research & Advanced Engineering
