Contribution of isoprene-derived organosulfates to free tropospheric aerosol mass

摘要: Recent laboratory studies have demonstrated that isoprene oxidation products can partition to atmospheric aerosols by reacting with condensed phase sulfuric acid, forming low-volatility organosulfate compounds. We identified compounds in free tropospheric single particle mass spectrometry during several airborne field campaigns. One of these organosulfates is as the sulfate ester IEPOX, a second generation product isoprene. The patterns IEPOX ambient data generally followed aerosol acidity and NOx dependence established studies. Detection was most sensitive using reduced ionization laser power, when it observed up 80% particles tropical troposphere. Based on calibrations, added > 0.4% remote tropics 20% regions downwind sources. In southeastern United States, acidic exposed fresh emissions, accumulation increased 3%. therefore one abundant organic measured aerosol. Our show acidity-dependent uptake mechanism which anthropogenic SO2 marine dimethyl sulfide emissions generate secondary biogenic throughout