Model 924 toxic air sampler is used for unattended collection of ambient air, and then toxic components are analyzed in the laboratory. The sampling instrument adopts modular design, including control unit, pump box assembly, weather protection cover and sampling head device. The sampler can be equipped with 1-4 sampling channels, including 3747mm filter (for collecting toxic metals and hexavalent chromium in air particles), adsorption tube (for collecting carbonyl compounds in the air), and sampling tank (for collecting air in addition to the sampling tank channel), the sampler can be equipped with multiple sampling channels. The sampler can only be connected to one sampling tank.