AbstractRate constants for the reactions of OH radicals and Cl atoms with 1‐propanol (1‐C3H7OH) have been determined over the temperature range 273–343 K by the use of a relative rate technique. The value of k(Cl + 1‐C3H7OH) = (1.69 ± 0.19) × 10−12 cm3 molecule−1 s−1 at 298 K and shows a small increase of 10% between 273 and 342 K. The value of k(OH + 1‐C3H7OH) increases by 14% between 273 and 343 K with a value of (5.50 ± 0.55) × 10−12 cm3 molecule−1 s−1 at 298 K, and further when combined with a single independent experimentally determined value at 753 K gives k(OH + 1‐C3H7OH) = 4.69 × 10−17T1.8 exp(422/T) cm3 molecule−1 s−1, which fits each data point to better than 2%. Two well‐established structure–activity relationships for H abstraction by OH radicals give accurate predictions of the rate constant for OH + 1‐C3H7OH, provided the β‐CH2 group is given an increased reactivity of a factor of about 2 over that for the structurally equivalent CH2 group in alkanes at 298 K.A quantitative product analysis was carried out at 298 K for the Cl‐initiated photooxidation of 1‐C3H7OH, using both FTIR and gas chromatography. HCHO, CH3CHO, and C2H5CHO were the only major organic primary products observed, although HCOOH was found in much smaller amounts as a secondary product. A key characteristic of the analysis was that the initial values of the product ratio [CH3CHO]/[C2H5CHO] were effectively constant for NO pressures between 0.15 and 0.3 Torr, but fell by about 35% as the pressure fell to 0.0375 Torr. From a detailed consideration of the mechanism for the oxidation, it is suggested that C2H5CHO, CH3CHO (+HCHO), and 3 molecules of HCHO are formed uniquely from CH3CH2CHOH, CH3CHCH2OH, and CH2CH2CH2OH radicals, respectively. On this basis, use of the product yields gives the branching ratios of 56, 30, and 14% for Cl atom reaction at the α‐, β‐, and γ‐CH positions in 1‐C3H7OH at 298 K. Given the very low temperature coefficients involved, little change will occur over tropospheric temperature ranges. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 110–121, 2002