Skincare Sun Protection and SPF 2 — Questions and Answers
Question 1: Physical (mineral) sunscreens work by:
- Absorbing UV radiation and converting it to heat
- Reflecting and scattering UV radiation away from the skin (Correct answer)
- Penetrating the epidermis to neutralize UV damage
- Stimulating melanin production for natural protection
Correct answer: Reflecting and scattering UV radiation away from the skin
Physical sunscreens containing zinc oxide and titanium dioxide work by reflecting and scattering UV rays away from the skin.
Question 2: Which two ingredients are the only FDA-approved active sunscreen ingredients classified as 'generally recognized as safe and effective' (GRASE)?
- Avobenzone and oxybenzone
- Zinc oxide and titanium dioxide (Correct answer)
- Octinoxate and homosalate
- Octisalate and octocrylene
Correct answer: Zinc oxide and titanium dioxide
The FDA has classified only zinc oxide and titanium dioxide as GRASE sunscreen ingredients in its updated sunscreen guidelines.
Question 3: What is photoaging?
- The skin's natural aging process unrelated to sun exposure
- Premature aging of the skin caused by chronic UV exposure (Correct answer)
- Aging of photographic materials used in skincare testing
- Sensitivity to light that causes rapid skin turnover
Correct answer: Premature aging of the skin caused by chronic UV exposure
Photoaging refers to premature skin aging caused by chronic sun exposure, resulting in wrinkles, pigmentation changes, and loss of elasticity.
Question 4: Which UV wavelength is almost entirely absorbed by the ozone layer and does not typically reach the Earth's surface?
- UVA
- UVB
- UVC (Correct answer)
- Visible light
Correct answer: UVC
UVC rays have the shortest wavelengths and highest energy but are absorbed by the ozone layer before reaching Earth's surface.
Question 5: The PA+ rating system (used on many Asian sunscreens) measures protection against which type of UV radiation?
- UVB rays
- UVC rays
- UVA rays (Correct answer)
- Infrared radiation
Correct answer: UVA rays
The PA+ system (Protection Grade of UVA) measures UVA protection, with more plus signs indicating higher UVA protection.
Question 6: Sunscreens with an SPF of 30 block approximately what percentage of UVB rays?
- 70%
- 87%
- 97% (Correct answer)
- 99.9%
Correct answer: 97%
SPF 30 blocks approximately 97% of UVB rays, SPF 50 blocks about 98%, and SPF 100 blocks approximately 99%.
Skincare Sun Protection and SPF 2
Physical (mineral) sunscreens work by: