Ozonolysis of methyl oleate monolayers at the air-water interface results in surprisingly rapid loss of material through cleavage of the C=C bond and evaporation/dissolution of reaction products. We determine using neutron reflectometry a rate coefficient of (5.7 ± 0.9) × 10(-10) cm(2) molecule(-1) s(-1) and an uptake coefficient of ∼3 × 10(-5) for the oxidation of a methyl ester monolayer: the...

In contrast with the textbook view of remote chemistry where HNO3 formation is the primary sink of nitrogen oxides, recent theoretical analyses show that formation of RONO2 (6ANs) from isoprene and other terpene precursors is the primary net chemical loss of nitrogen oxides over the remote continents where the concentration of nitrogen oxides is low. This then increases the prominence of questi...

[1] Previous attempts to establish global mass balances for polychlorinated dioxins and furans (PCDD/Fs) have focused on the terrestrial sink, thereby neglecting deposition to the oceans and atmospheric losses. In this study, the atmospheric sink of polychlorinated dioxins and furans (PCDD/Fs) was calculated on the basis of their presence in soils. OH radical ([OH]) depletion reactions compete ...

The lifetime risk of acquiring HIV infection in many rural as well as urban areas of southern Africa is currently as high as two-in-three. For women, much of this risk still accrues rapidly at young ages despite high levels of knowledge about HIV/AIDS. Thus, programmes that are more participatory and address underlying structural and community-level factors appear to be essential. We use cross-...

Sulphur hexafluoride (SF 6 ) gas is the frequently consumed in High Voltage (HV) applications due to its high dielectric permittivity and arc-quenching property. However, long Atmospheric Lifetime (AL), Global Warming Potential (GWP), other environmental concerns there a need for new sustainable as an alternative SF . Therefore, this research, we present dichlorodifluoromethane (R-12) conjuncti...

Aircraft and satellite observations indicate the presence of ppt (ppt ≡ pmol/mol) levels of BrO in the free troposphere with important implications for the tropospheric budgets of ozone, OH, and mercury. We can reproduce these observations with the GEOS-Chem global tropospheric chemistry model by including a broader consideration of multiphase halogen (Br-Cl) chemistry than has been done in the...

Beryllium was released into the air from routine operations and three accidental fires at the Rocky Flats Plant (RFP) in Colorado from 1958 to 1989. We evaluated environmental monitoring data and developed estimates of airborne concentrations and their uncertainties and calculated lifetime cancer risks and risks of chronic beryllium disease to hypothetical receptors. This article discusses expo...

1. INTRODUCTION Over the past 60 years, for the reasons shown in Figure 1, the engineering industry has found halogen-containing cleaning solvents to be technically very effective. More recently, the chemical inertness, non-flammability, low toxicity and convenience of 1,1,2-trichlorotrifluoroethane, has led to the wide use of products based on CFC-113 in electronics applications. Evidence of t...