The pulmonary toxicity, induced by multi-wall carbon nanotubes in mice, was studied after 30-day and 60-day inhalation exposure. The mice were exposed to multi-wall carbon nanotubes aerosol with weighted mean concentration of 32.61 mg/m(3), once in very two days, 6 hours in an exposure day. After 30-day and 60-day inhalation exposure, the pulmonary toxicity of multi-wall carbon nanotubes was assessed using biochemical indices in bronchoalveolar lavage fluid and pathological examination. It was found that the aerosolized multi-wall carbon nanotubes did not induce obvious pulmonary toxicity in 30-day exposure group, but induced severe pulmonary toxicity in 60-day exposure group.
