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The first experimental study of the reaction CIO + CH302 -* products (1) is reported. The rate coefficient Aq and the product distributions were investigated in the modulated photolysis of Cl2/CH4/Cl20/02 mixtures. Reactants and products have been monitored by using UV-vis and Fourier-transform infrared gas-phase absorption spectroscopies. The value of A, was found to be equal to (3.1 ± 1.7) X 10"12 cm3 molecule"1 s'1 at 300 K and 240 Torr total pressure. The product channel forming ClOO and CH30 appears to be the dominant pathway at 300 K. The subsequent oxidation of CH30 to CH20 and its partial photolysis into Ff and HCO leads to enhanced production of odd hydrogen (OH, H02) radicals. Consequently, high concentrations of OH radicals can build up, leading to an additional source of active chlorine via the reaction HC1 + OH -Cl + H20, which destroys ozone by catalytic reactions. This strongly suggests that reaction 1 can play a substantial role in the photochemical processes that take place under stratospheric "ozone hole" conditions. 1986, 321, 755.

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Environmental context. Increasing global plastic production adds plastic debris to the environment. We show that potentially harmful additives present in plastic particles are released to water at an increased rate when material properties change by aging due to exposure to high temperature and especially to UV radiation. For risk assessment of such plastic additives, more information on their degradation products and their toxicity is needed.Abstract. Recycled plastic granules of high-density polyethylene, polyvinyl chloride and polystyrene the size of microplastics were exposed to artificial aging conditions (2000 h; photooxidative and thermo-oxidative) to simulate their fate outdoors. Their potential to leach into water during the aging process was investigated using column percolation tests. Aging-related changes on the surface of the material were characterised by IR measurements indicating oxidation reactions with the formation of new adsorption bands (C=O, C-O and OH), especially in the case of photooxidative aging. These findings were confirmed by the identification of leachable organic compounds. Leaching of total organic carbon, Cl, Ca, Cu and Zn is clearly affected by changes due to aging, and their release is increased after photooxidative aging. In general, exposure to photooxidative conditions shows a greater influence on aging and thus on leaching and seems to be the more important mechanism for the aging of microplastic in the environment. Comparison with the total content of inorganic species revealed that, for most elements, less than 3% of the total content is released after 2000 h of photooxidative aging.

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