In recent years, high fine particulate (PM2.5) pollution episodes with ozone (O3) levels have been observed in Shanghai from time to time. However, their occurrence and characteristics remain poorly understood. Meanwhile, as a major precursor of tropospheric hydroxyl radical (OH) that initiates the formation hydroperoxyl organic peroxy radicals, HONO would inevitably affect O3, but its role O3 ...

Abstract. Ozone (O3), a potent greenhouse gas that is detrimental to human health, typically found in elevated concentrations within biomass burning (BB) smoke plumes. The radical species OH, HO2, and RO2 (known collectively as ROx) have central roles the formation of secondary pollutants including O3 but are poorly characterized for BB We present measurements total peroxy ([XO2] ≡ [HO2] + [RO2...

In previous studies in this laboratory, highly purified liver microsomal cytochrome P-450 was shown to catalyze the hydroperoxide-dependent hydroxylation of a variety of substrates in the absence of NADPH, NADPH-cytochrome P-450 reductase, and molecular oxygen, and evidence was obtained that the oxygen atom in the product was derived from the peroxide. To determine whether the cytochrome funct...

Nitrogen exchange between the atmosphere and biosphere directly influences atmospheric composition. While much is known about mechanisms of NO and N2O emissions, instrumentation for the study of mechanisms contributing to exchange of other major nitrogen species is quite limited. Here we describe the application of a new technique, thermal dissociation-laser induced fluorescence (TD-LIF), to ed...

The ring closure in unsaturated alkyl peroxy radicals can be a competitive process the atmospheric oxidation of biogenic organic compounds.

The Regional Atmospheric Chemistry Mechanism (RACM) is a highly revised version of the RADM2 mechanism (RACM; Stockwell et al., 1997). The changes to the inorganic chemistry were relatively minor but there were substantial changes for many organic compounds. These revisions included improvements to the mechanisms for the oxidation of alkanes by HO radical, the ozonolysis of alkenes, the reactio...

Abstract. HO2 uptake kinetics onto ambient aerosols play pivotal roles in tropospheric chemistry but are not fully understood. Field measurements of aerosol chemical and physical properties should be linked to molecular-level kinetics; however, given that the reactivity is low, traditional analytical techniques unable achieve this goal. We developed an online approach precisely investigate lowe...

The nearly rotationally resolved spectrum of the A (2)A(')<--X (2)A(") 0(0)(0) transition of perdeutero methyl peroxy near 1.35 microm has been studied via pulsed cavity ringdown spectroscopy. Albeit, this is a weak transition, it is possible to observe the spectrum under jet-cooled conditions (approximately 15 K) by combining a source of narrow-bandwidth radiation (approximately 250 MHz) with ...

The formation of secondary organic aerosol (SOA) from the oxidation of β-pinene via nitrate radicals is investigated in the Georgia Tech Environmental Chamber (GTEC) facility. Aerosol yields are determined for experiments performed under both dry (relative humidity (RH) < 2 %) and humid (RH= 50 % and RH= 70 %) conditions. To probe the effects of peroxy radical (RO2) fate on aerosol formation, “...