Although it is generally recognized that SOz and NOx (s NO + NOz) are the precursors of the strong acids (i.e., HzS04 and HN03) found in precipitation,! the detailed mechanisms for the oxidation of these compounds and their incorporation into atmospheric liquid water are not fully understood. In principle, the incorporation of acids into cloudor rainwater can take either or both of two pathways...

[1] Secondary organic aerosol (SOA) formed from partitioning of oxidation products of anthropogenic and biogenic volatile organic compounds (VOCs) accounts for a substantial portion of atmospheric particulate matter. In describing SOA formation, it is generally assumed that VOC oxidation products rapidly adopt gas-aerosol equilibrium. Here we estimate the equilibration timescale, teq, of SOA ga...

The global budget of atmospheric CH4 , which is on the order of 500-600 Tg CH4 per year, is mainly the result of environmental microbial processes, such as archaeal methanogenesis in wetlands, rice fields, ruminant and termite digestive systems and of microbial methane oxidation under anoxic and oxic conditions. This review highlights recent progress in the research of anaerobic CH4 oxidation, ...

Sulfate particles play a key role in the air quality and the global climate, but the heterogeneous formation mechanism of sulfates on surfaces of atmospheric particles is not well established. Carbonates, which act as a reactive component in mineral dust due to their special chemical properties, may contribute significantly to the sulfate formation by heterogeneous processes. This paper present...

Ammonia-oxidizing bacteria (AOB) are thought to contribute significantly to N2O production and methane oxidation in soils. Most of our knowledge derives from experiments with Nitrosomonas europaea, which appears to be of minor importance in most soils compared to Nitrosospira spp. We have conducted a comparative study of levels of aerobic N2O production in six phylogenetically different Nitroso...

The heterogeneous oxidation of pure erythritol (C(4)H(10)O(4)) and levoglucosan (C(6)H(10)O(5)) particles was studied in order to evaluate the effects of atmospheric aging on the mass and chemical composition of atmospheric organic aerosol. In contrast to what is generally observed for the heterogeneous oxidation of reduced organics, substantial volatilization is observed in both systems. Howev...

Isoprene is a significant source of atmospheric organic aerosol; however, the oxidation pathways that lead to secondary organic aerosol (SOA) have remained elusive. Here, we identify the role of two key reactive intermediates, epoxydiols of isoprene (IEPOX = beta-IEPOX + delta-IEPOX) and methacryloylperoxynitrate (MPAN), which are formed during isoprene oxidation under low- and high-NO(x) condi...

The oxidation of atmospheric CH4 in upland soils is mostly mediated by uncultivated groups of microorganisms that have been identified solely by molecular markers, such as the sequence of the pmoA gene encoding the β-subunit of the particulate methane monooxygenase enzyme. The objective of this work was to compare the activity and diversity of methanotrophs in Amazonian Dark Earth soil (ADE, Ho...

The kinetics of the reaction between soot nanoparticles and molecular oxygen were studied by tandem differential mobility analysis (TDMA). The particles were extracted from the tip of an ethene diffusion flame. Reactions were studied at atmospheric pressure in mixtures of nitrogen and oxygen. The studies involved particles of an initial mobility diameter of 30 nm over broad ranges of temperatur...