The original temperature of sodium lamp is quitely different with running.Without breathing system ,the reflector will be crakered by nocuous gas ,causing more light lost.

• 钠灯由于灯亮时与灯来时的温度差异很大，若灯体不带呼吸系统时，反射器容易被有害气体腐蚀而产生较大光损。