The effects of isoprene and NO x on secondary organic aerosols formed through reversible and irreversible uptake to aerosol water

摘要: Abstract. Isoprene oxidation produces water-soluble organic gases capable of partitioning to aerosol liquid water. The formation of secondary organic aerosols through such aqueous pathways (aqSOA) can take place either reversibly or irreversibly; however, the split between these fractions in the atmosphere is highly uncertain. aim this study was characterize the reversibility aqSOA formed from isoprene at a location eastern United States under substantial influence both anthropogenic and biogenic emissions. reversible and irreversible uptake water-soluble organic water characterized Baltimore, Maryland, USA, using measurements particulate carbon (WSOC p) in alternating dry ambient configurations. WSOC p evaporation with drying observed systematically throughout late spring and summer, indicating during times. We show through time lag analyses that concentrations, including the evaporates with drying, peak 6 11 h after isoprene maxima 9 h. absolute reversible as well relative amount reversible aqSOA, increased decreasing NO x ∕  isoprene ratios, suggesting that epoxydiol (IEPOX) other low-NO products may be responsible for effects. relationships and suggest process occurs widely atmosphere, and is likely more important locations by higher isoprene and/or lower levels. This work underscores importance of accounting oxidation products particles.