Abstract
Mice were exposed to various concentrations of formaldehyde or acrolein. Concentration-response relationships were developed by measuring per cent decrease in respiratory rate, indicating upper respiratory tract sensory irritation. Relationships are presented between the concentration associated with a 50% respiratory decrease and TLVs. A summary of other animal inhalation studies is presented. The basis for the acrolein and formaldehyde TLVs are reviewed. Mice exposed for 4 days showed increasing sensitivity daily for both compounds. A re-evaluation of the TLVs is suggested.