A lamp includes a housing having a solid peripheral wall between an opening and an electrical connector respectively at two ends of the housing, maintaining the appearance integrity of the lamp. A cooling module is fixed in the housing. At least one wind channel is defined between the cooling module and the opening of the housing. A light-emitting element is coupled to the cooling module. A circuit board is fixed in the housing and electrically connected to the electrical connector and the light-emitting element. An air cleaner includes a generator body and at least one emitter. An air passage is defined between an inner face of the solid peripheral wall of the housing, the cooling module and the circuit board. The at least one emitter of the air cleaner is mounted in the air passage, providing enhanced air cleaning effect.