There is energy moving in waves all around you. You cannot see, touch or feel these waves but they are essential to your everyday life. Every time you turn on the radio, use wif-fi or your cell phone you are tapping into invisible electromagnetic energy that travels in waves. Electromagnetic waves go from very long (radio waves), to very short (gamma rays). Some of these rays, especially the ones on the shorter end, can be very damaging for your health.
Ultraviolet (UV) energy is practically invisible to the naked eye. It is located at the very edge of the visible light spectrum (as soon as we enter the light spectrum we encounter the notorious blue light). UV is divided into three parts depending on its range of wavelengths. UVA is 290-320nm, UVB 320-400 nm and UVC 100-290 nm. UVC is of no concern to us, as it is completely filtered out by our ozone layer.
UVB makes up 5-10% of UV radiation and is the primary cause of sunburn. It penetrates the top levels of the skin’s layers, stimulating the skin to produce more melanin and thicker epidermis, which is what we recognize as a tan.
UVA makes up 90- 95% of UV radiation is the primary cause of long term skin damage including loss of elasticity and wrinkling. It penetrates much deeper into the skin than UVB and its effects are seen much later compared to the immediate inflammatory effects of UVB. UVA can create reactive oxygen species (highly reactive chemicals created by O2) that can indirectly damage our DNA.
Both UVA and UVB play a role in skin damage and the formation of skin cancer. It is fundamental to protect yourself from both UVA & UVB for real sun protection.
When a UV filter blocks both UVB and UVA it is full spectrum protection.
It has been suggested that using sunscreens that only block UVB light may actually increase the risk of skin cancer. This is because sunscreens that only block UVB radiation are blocking out the 5 -10 % of the UV radiation that you are exposing yourself to, while at the same time stopping your skin from burning and allowing you to dangerously over-expose yourself to the 90 - 95% of UVA radiation without realizing it. When you block UVB you prevent skin inflammation and sunburn, nature's warning sign that your skin is being badly damaged and that you should get out of the sun. You could think of UVB sun filters like pain killers that remove the symptoms without addressing the cause of the discomfort.
Many chemical (organic) filters do not block both UVA and UVB and must be combined to create a sunscreen that offers full protection. In terms of mineral filters, titanium dioxide is very good at blocking UVB, but not so great at blocking UVA’s. Zinc oxide is number one, naturally blocking both UVA and UVB light.
Whenever choosing a sunscreen it is not only important to look at the UV filters used but if the product is declared to be broad spectrum protection. Otherwise, you risk doing exactly what you didn't want to do, that is, overexposing and damaging your skin with harmful UV radiation.
Kuna nishati inayosonga katika mawimbi karibu nawe. Hatuwezi kuona, kugusa au kuhisi mawimbi haya lakini ni muhimu kwa maisha yako ya kila siku. Kila mara unapowasha redio, kutumia Wi-Fi au simu yako ya mkononi, unashiriki katika nishati isiyoonekana ya umeme ambayo husafiri kwa mawimbi. Mawimbi ya umeme huanzia mawimbi marefu sana (wimbi la redio) hadi mawimbi mafupi sana (mionzi ya gamma). Baadhi ya miale hiyo, hasa ile iliyo kwenye ncha fupi, yaweza kuharibu sana afya yako. Nishati ya ultraviolet (UV) haiwezi kuonekana kwa jicho la kawaida. Ni sehemu ya mwisho kabisa ya mwangaza unaoonekana (kama tu tunapoingia kwenye mwangaza huo tunakutana na mwangaza wa bluu unaojulikana sana). UV imegawanywa katika sehemu tatu kulingana na safu yake ya urefu wa wimbi. UVA ni 290-320 nm, UVB ni 320-400 nm na UVC ni 100-290 nm. UVC haisumbui, kwa kuwa hufichwa kabisa na tabaka letu la ozoni. UVB ni moja ya sababu kuu ya kuchomwa na jua. Inaingia katika tabaka za juu za ngozi, na kuchochea ngozi kutengeneza melanin zaidi na epidermis nzito, ambayo ni nini sisi kutambua kama tan. UVA ni moja ya sababu za msingi za uharibifu wa ngozi wa muda mrefu, ikiwa ni pamoja na kupoteza elasticity na wrinkles. Inaingia ndani zaidi ya ngozi kuliko UVB na athari zake zinaonekana baadaye ikilinganishwa na athari za mara moja za uvimbe wa UVB. UVA inaweza kuunda aina za oksijeni (kemikali zenye athari kubwa zinazozalishwa na O2) ambazo zinaweza kuharibu DNA yetu kwa njia isiyo ya moja kwa moja. UVA na UVB huchangia athari za ngozi na kuunda saratani ya ngozi. Ni muhimu kujilinda dhidi ya UVA na UVB kwa ajili ya ulinzi halisi wa jua. Filter ya UV-B inazuia UV-B na UVA, na inatoa ulinzi kamili wa wigo. Kwa mfano, kuna watu wanaosema kwamba kutumia krimu za kuhifadhi jua ambazo huzuia tu mwangaza wa UVB kunaweza kuongeza hatari ya kupata kansa ya ngozi. Kwa sababu sunscreens ambazo huzuia tu mionzi ya UVB zinazuia 5-10% ya mionzi ya UV ambayo unajidhihirisha, wakati huo huo unazuia ngozi yako kutoka kwa kuchoma na kuruhusu wewe kujiweka hatari zaidi kwa 90-95% ya mionzi ya UVA bila kugundua. Wakati wa kuzuia UVB, unazuia uvimbe wa ngozi na kuchomwa na jua, ishara ya onyo ya asili kwamba ngozi yako imeharibiwa sana na unapaswa kutoka kwa jua. Vifuniko vya jua vya UVB ni dawa ya kupunguza maumivu ambayo huondoa dalili bila kushughulikia sababu ya shida. Vifuniko vingi vya kemikali (organiki) havizuii UVA na UVB na lazima viunganishwe ili kuunda kinga ya jua ambayo hutoa ulinzi kamili. Kwa upande wa vichungi vya madini, titanium dioksidi ni nzuri sana katika kuzuia UVB, lakini si kubwa sana katika kuzuia UVA. Zinc oxide ni moja ya aina ya nyuzi za UV-A na UV-B. Wakati wa kuchagua sunscreen, ni muhimu kuangalia si tu filters UV kutumika, lakini kama bidhaa ni alitangaza kuwa ulinzi pana-spectrum. Vinginevyo, unaweza kufanya kile ambacho hutaki kufanya, yaani, kuharibu ngozi yako na mnururisho hatari wa UV.