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Environmental fate & pathways

Phototransformation in air

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Description of key information

After evaporation or exposure to the air, acrylic acid will be slowly degraded by photochemical processes.
Calculated half-life for a 24-hr day and 0.5E+06 OH/cm3: 39.6 hr

Key value for chemical safety assessment

Additional information

There are no experimental data on photodegradation of acrylic acid. According to Q(SAR) data using SRC AOP v1.92, AA will be slowly degraded by photochemical processes after exposure to the air reacting with the photochemically produced hydroxyl radicals and with ozone (calculated half-life for a 24-hour day and 0.5E06 OH/cm3: 39.59 hours (= 1.65 days); for a 24-hour day and 7E11 O3/cm3: 6.55 days) (BASF SE, 2008). Since AA shows a vapour pressure of 5.29 hPa at 25 °C and a Henry's Law constant of 0.029 Pa*m3/mol, no significant evaporation from the water surface can be expected. Thus, photodegradation may not play a considerable role under environmental conditions.