The COUNCIL will discuss the recent advisory letter authored by the COUNCIL's Health Effects Subcommittee in response to a August 11, 2003 request from EPA's Office of Air and Radiation (OAR) and Office of Policy, Economics and Innovation (OPEI). Of specific interest to OAR and OPEI was HES advice pertaining to cessation lags, i.e. the time delay between reductions in air pollution and reductions in adverse health effects.