Abstract: A sensor device is disclosed for providing end of service life indication for an air purification filter. The sensor device has a cylindrical housing for insertion into a sorbent bed of a filter, and can be removed from the bed and reused at the end of the filter service. One or more sensors inside the housing are configured to sense physical/chemical characteristics of air passing through the sorbent bed, and to provide associated data to a sensor conditioning board within the housing. The sensor conditioning board processes the received data and conditions the data as desired. The housing is receivable in a cavity formed in the filter bed. A receiving structure receives the housing therein. Data from the one or more sensors can be used to calculate predicted end of service life of the filter. Other embodiments are described and claimed.