Abstract
Particle formation by radiolysis was observed in the neutralizer of the differential mobility analyzer (DMA) in air or N2 under presence of O3 and/or SO2. The effects of SO2 concentration, relative humidity and O3 concentration on the particle formation in the neutralizer were investigated. This particle formation may cause artifacts in aerosol size-measuring using a DMA. The particle number concentration increased with increasing of SO2 concentration and relative humidity. In low humidity condition, remarkable increase of the number concentration was observed when 0.1 ppm of O3 was added to SO2 (0.2 ppm)/N2 (H2O < 15 ppm) mixture. The mechanisms of the particle formation in the neutralizer under presence of O3 were discussed.
