4 documents found, page 1 of 1
CCN activity and organic hygroscopicity of aerosols downwind of an urban region...
Thalman, Ryan M.; Sá, Suzane S. de; Palm, Brett B.; Barbosa, H. M. J.; Pöhlker, Mira L.; Alexander, Michael Lizabeth; Brito, Joel F.; Carbone, SamaraDuring the Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign, size-resolved cloud condensation nuclei (CCN) spectra were characterized at a research site (T3) 60 km downwind of the city of Manaus, Brazil, in central Amazonia for 1 year (12 March 2014 to 3 March 2015). Particle hygroscopicity (κCCN) and mixing state were derived from the size-resolved CCN spectra, and the hygroscopici...
Influence of urban pollution on the production of organic particulate matter fr...
Sá, Suzane S. de; Palm, Brett B.; Campuzano-Jost, Pedro; Day, Douglas A.; Newburn, Matt K.; Hu, Weiwei; Isaacman-VanWertz, Gabriel A.; Yee, Lindsay D.The atmospheric chemistry of isoprene contributes to the production of a substantial mass fraction of the particulate matter (PM) over tropical forests. Isoprene epoxydiols (IEPOX) produced in the gas phase by the oxidation of isoprene under HO2-dominant conditions are subsequently taken up by particles, thereby leading to production of secondary organic PM. The present study investigates possible perturbations...
Isoprene photochemistry over the Amazon rainforest
Liu, Yingjun; Brito, Joel F.; Dorris, Matthew R.; Rivera-Ríos, Jean C.; Seco, Roger; Bates, Kelvin H.; Artaxo, Paulo; Duvoisin, Sérgio JrIsoprene photooxidation is a major driver of atmospheric chemistry over forested regions. Isoprene reacts with hydroxyl radicals (OH) and molecular oxygen to produce isoprene peroxy radicals (ISOPOO). These radicals can react with hydroperoxyl radicals (HO2) to dominantly produce hydroxyhydroperoxides (ISOPOOH). They can also react with nitric oxide (NO) to largely produce methyl vinyl ketone (MVK) and methacro...
Urban pollution greatly enhances formation of natural aerosols over the Amazon ...
Shrivastava, Manish K.; Andreae, Meinrat O.; Artaxo, Paulo; Barbosa, H. M. J.; Berg, Larry K.; Brito, Joel F.; Ching, Joseph; Easter, Richard C.One of the least understood aspects in atmospheric chemistry is how urban emissions influence the formation of natural organic aerosols, which affect Earth’s energy budget. The Amazon rainforest, during its wet season, is one of the few remaining places on Earth where atmospheric chemistry transitions between preindustrial and urban-influenced conditions. Here, we integrate insights from several laboratory meas...