7. Ib puag ncig zoo:
Lub siab siab sodium lub teeb qhov chaw nws tus kheej yog qhov tsis yooj yim, thiab lub teeb qhov chaw muaj cov khoom tsis zoo xws li mercury, uas tuaj yeem ua rau muaj kuab paug rau ib puag ncig. LED txoj kev teeb yog tsis muaj txhuas, tsis muaj mercury, tsis muaj infrared, Ultraviolet-dawb thiab ntsuab.
