UVA Radiation:
- Causes skin tanning
- Causes oxidative DNA stress
UVB Radiation
- Causes skin burns
- Directly damages DNA
DNA damage causes skin cancer
Sun Exposure & Skin Cancer
Ultraviolet Light (UV)
SKIN CANCER STATISTICS
- 1 out of 5 Americans will develop skin cancer by age 70
- 5 or more sunburns increase your risk of melanoma
- The most common skin cancer is basal cell carcinoma (~3.6 million diagnosed each year)
- The second most common skin cancer is squamous cell carcinoma (~1.8 million diagnosed each year)
- 186,680 melanomas are estimated to be diagnosed in 2023
When You Are Exposed to the Sun (and UV radiation)
Sunny Day:
- UVA
- UVB
Cloudy or Rainy Day:
- UVA passes through to your skin
- UVB is partially blocked
Through Window Glass:
- UVA passes through to your skin
- UVB is blocked
Note: Only car windshields protect against UVA, but it passes through the side and rear windows
Reflection:
- Snow reflects ~85-90%
- Water reflects ~15-20%
- Sand reflects ~15%
- Dark soil reflects ~10-20 %
Protecting Your Skin
Basic Tips:
- Avoid indoor tanning
- Seek shade
- Avoid peak sun (10 AM to 4 PM)
- Sun Protection
Types of Topical Protection:
Sunblock vs. Sunscreen:
- Sunblock shields from UVA/UVB with zinc oxide and/or titanium oxide
- Sunscreen contains chemicals that absorb/scatter UV rays
Broad Spectrum: Protects against both UVA & UVB
Sun Protective Factor (SPF):
- Amount of protection from sunburn
- If you take 10 minutes to burn without sunscreen, it will take you 300 minutes to burn with SPF30 sunscreen
Water Resistance:
- Water resistant: 40 minutes in the water
- Very water resistant: 80 minutes in the water
How to Apply
- Apply 15-20 minutes before going outdoors
- Spray sunscreens should be rubbed in
- Apply 1 ounce (2 tablespoons) to every area of your skin
- Reapply after 1-2 hours in direct sunlight, or after swimming, sweating, or toweling off
- Don't forget your lips and feet, plus remember to wear sunglasses to protect your eyes
Wearable Sun Protection
Hats:
- 4-inch brim with a tight weave
- "If you can look up and see the sun, the sun can see you!"
Clothing:
- Tight weave fabrics without holes
- UV Protective Factor (UPF) is the fraction of sun's rays that penetrate the fabric—UPF 50 allows 1/50th of UV radiation to reach skin
Sunglasses:
- 100% UVA or UVB blockers or a UV 400 signature
- The larger, the better lens—especially wraparound styles
- Polycarbonate are the most shatterproof
Other Sun Protection Recommendations
Everyone:
- Sunscreen 30 SPF or higher and water-resistant
Babies Under 6 Months:
- Sun protection using clothing & hats, as well as seeking shade
- Apply sunscreen in small amounts to any unprotected skin
Children Above 6 Months:
- Look for sunscreen made for children—often contain physical blockers of the sun that are less irritating to the skin
Sensitive Skin:
- Sunscreen daily (for everyone)