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Environmental fate & pathways

Phototransformation in air

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Description of key information

EMA does not possess UV-absorbing structures. Therefore, direct photolysis is not expected to occur to any significant degree.
Photodegradation, with its short half-lifes is estimated to be the major sink for any methacrylic acid and all esters in the category released to the environment.

Key value for chemical safety assessment

Additional information

Experimental data does not exist on EMA. Experiments with model atmospheres with MMA indicate a half-life of 2.7 hours in urban air and > 3 hours in rural areas (determined in the presence of 0.2 ppm or 2 ppm of nitrogen oxides with an initial concentration of 4 ppm of MMA (Joshi et al., 1982). Therefore, by analogy to MMA, EMA is expected to degrade in the presence of nitrogen oxides.

EMA is expected to photodegrade in the atmosphere either by reaction with photo-chemically produced hydroxyl radicals or by reaction with ozone. The reaction half-life for the atmospheric oxidation of EMA by hydroxyl radicals range has been estimated to be 19.5 h. This is consistent with a slight trend of shorter half-lifes with increasing molecular weight within the category of lower methacrylate esters. For the reaction with ozone an atmospheric half-life of approximately one day has been calculated for all lower methacrylate esters, including EMA. A combined reaction half-life is calculated to be 10.8 h.