Chemical vs. Physical: Yikuphi Uhlobo umuthi ongakuvikela ngokuphelele elangeni Khipha ku-internet?

Ukukhetha lo muthi ingase yibe yinto exakayo. Kunezinhlobo eziphilayo futhi wezinto ezingaphili, futhi ijagoni like-UV, SPF futhi ebanzi-spectrum ukuhlunga. Craig Burkhart, likaprofesa nezesikhumba at the University of North Carolina at Chapel Hill, uyachaza.

-Heidi Mitchell

Chemical vs. Physical

Mhlawumbe imithi yokuzivikela elangeni ngokuvamile esetshenzisiwe “wezinciphisi chemical.” Ziqukethe carbon compounds esenziwe laboratory. Abanye 22 amakhemikhali babé itholakale U.S. avikele isikhumba kusukela imisebe yelanga eyingozi kusukela kwakwakhe PABA lokuqala yasungulwa ngo-1940.

CORBIS
blocker Physical woza e ezimbili izinhlobo: amaminerali zinc oxide ne-titanium dioxide-zemvelo kutsho phansi ukuze izimpushana emihle. Lezi esetshenziswa ukushiya ezisalayo lapho white amasu esikhumbeni, kodwa processing zanamuhla baye ngokuyinhloko obekuzakuphela ukuthi. “Inzuzo blocker ngokomzimba wukuthi abazi ukubola kwangena elangeni, ngakho they kwakuthiwa abe nokuphila isikhathi eside esikhumbeni sakho,” Dr. Burkhart uthi. Yini embi ngalo: “Bathi zivama ukuzizwa okunamafutha.”

I-Food and Drug Administration ukhetha abakhiqizi basebenzisa igama elithi organic lapho ebhekisela ezinhlekeleleni amakhemikhali imithi yokuzivikela elangeni-ngenxa yokuthi ziqukethe carbon compounds-futhi wezinto ezingaphili for sunblocks ngokomzimba.

Rays of Light

kuza ukuchayeka emisebeni Ilanga ngo izinhlobo ezintathu uma ifinyelela Earth: UVB imisebe, ngokuyinhloko obangela okubangela yilanga, futhi UVA1 futhi UVA2, okuyinto yobudala isikhumba. “Kodwa [zonke ezintathu] nesandla emdlavuzeni wesikhumba,” Dr. Burkhart uthi. Imithi Yokuzivikela Elangeni Nesifo Okubanzi-spectrum enzelwe ukuvikela uhla yamaza ngemisebe okwathatha isikhathi eside.

Lapho ukukhanya kwelanga hits isikhumba, wezinciphisi chemical amunca esebenzayo emisebe yama-UV nokukhululwa amandla azo kabi ngezindlela okungenangozi. Lapho emisebe yama-UV hit isikhumba camera blocker ngokomzimba, they ziyabonakala futhi abakwazi ukungena isikhumba. I-FDA uncoma ukusebenzisa umuthi ongakuvikela ngokuphelele elangeni nge SPF, noma ilanga yokuvikela factor, okungenani 15.

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