- 1. The Difference Between PA and SPF
The PA level on a sunscreen measures the UVA protection it provides. UVA rays have the ability to penetrate deeper into skin to affect the dermis is one of the main causes premature ageing like wrinkles, dryness and pigmentation. Having a sunscreen with a high PA level is especially important for people leaving in Singapore because in Southeast Asia, we are exposed to higher levels of UVA rays.
In 1996, the Japanese Cosmetic Industry Association (JCIA) introduced a three-tiered PA grading to measure UVA protection. UVA protection is measured with the Japanese developed Persistent Pigment Darkening (PPD) method.
However, a few years ago, the JCIA has modified their PA system to accommodate the higher UVA protection that sunscreens now provide. Presently, sunscreens with PA++++ provide the greatest protection against UVA damage and consequently, photoageing.
SPF (Sun Protection Factor), on the other hand, measures the level of UVB protection. UVB rays are responsible for causing sunburn, skin damage and can also contribute to skin cancer. The number of your SPF signifies the number of times longer it will protect your skin from burning.
For example, if your skin would typically burn after 10 minutes in the sun, then an SPF 20 would prevent it from burning for 20 times longer (approximately 200 minutes). However, regardless of how high your sunscreen’s SPF levels, most experts and doctors would recommend reapplication every two hours if you’re under the sun.