[en] Full text: We investigated the atmospheric aerosols using the cavity ring-down laser absorption spectroscopy. A modified cavity ring-down technique is used to investigate the optical extinction of the atmospheric aerosols. We also determined the extinction coefficient of atmospheric air (2.06x10^-6 cm^-1). The experimental system is composed of a pulsed dye laser pumped by the second harmonic of a Nd:YAG laser (Δν≅1cm^-1, 1 kHz, 0.310W), optical system, the ring-down cavity, the detection system for the ring-down signal, and clean dry air system. Most measurements were carried out at l=583.5 nm. A 65 cm cavity filled with dry, filtered air resulted in characteristic lifetime of 1.6 ms with the dye laser pulse width of 32 ns, which is comparable to the reported values. The effects of non-absorbing aerosols, such as acetone, smoke, ethanol, hot water steam and gas discharge on the cavity ring-down times were investigated experimentally. (authors)