The ultraviolet absorption spectrum of CH2FCFHO2 radicals and the kinetics and mechanism of their reaction with NO have been studied in the gas phase at 296 K using a pulse radiolysis technique. A long path-length Fourier transform infrared technique was used to study the atmospheric fate of CH2FCFHO radicals. Absorption cross sections were quantified over the wavelength range 220-300 nm. At 240 nm, sigma(CH2FCFHO2) (3.28 +/- 0.40) x 10(-18) cm(2) molecule(-1). Errors are statistical (2 standard deviations) plus our estimate of potential systematic uncertainty (10%). Monitoring the rate of NO2 formation using a monitoring wavelength of 400 nm allowed a lower limit of kappa(3) > 8.7 x 10(-12) cm(3) molecule(-1) s(-1) to be derived for the reaction of CH2FCFHO2 radicals with NO. The alkoxy radical CH2FCFHO was found to undergo C-C bond scission rapidly with a rate greater than 6 X 10(4) s(-1). The Cl-atom-initiated oxidation of HFC-152 in air in the presence of NOx gave HC(O)F as the sole carbon-containing product. The carbon balance was 91 +/- 10%. Results are discussed with respect to the atmospheric chemistry of HFC-152. As part of the present work, a relative rate technique was used to measure rate constants of (6.7 +/- 0.8) x 10(-13) and (3.8 +/- 1.1) x 10(-11) cm(3) molecule(-1) s(-1) for the reaction of CH2FCH2F with Cl and F atoms, respectively.