The UV absorption cross-sections and the rate coefficients for the ozonolysis of styrene, α-methylstyrene, β-methylstyrene, 2-methylstyrene and indene have been investigated. The absorption spectra were measured using a diode array spectrometer over the wavelength range 260–310 nm at 328 K. Large absorption cross-sections (∼10−18 cm2 molecule−1) were observed for the investigated compounds over the wavelength range 260–280 nm, while their absorption cross-sections decreased sharply above 290 nm with values of about 10−20 to 10−21 cm2 molecule−1 around 310 nm. The rate coefficients for the reactions of the aromatic compounds studied and O3 measured in a simulation chamber using both absolute and relative methods at 295 ± 3 K and atmospheric pressure were (in 10−17 cm3 molecule−1 s−1): (1.5 ± 0.3), (1.8 ± 0.4), (3.1 ± 0.6) and (16 ± 4) for styrene, α-methylstyrene, 2-methylstyrene and indene, respectively. The data obtained were used to estimate the lifetimes of the investigated compounds.