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, σ_CH2FCFHO2 = (3.28 ± 0.40) × 10^-18 cm² 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 k₃ > 8.7 × 10^-12 cm³ 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 × 10⁴ s^-1. The Cl-atom-initiated oxidation of HFC-152 in air in the presence of NO_x 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) × 10^-13 and (3.8 ± 1.1) × 10^-11 cm³ molecule^-1 s^-1 for the reaction of CH₂FCH₂F with Cl and F atoms, respectively.