ALL ABOUT: PA and PPD. What sunscreen says.

 

 

We continue our journey into the world of sun protection, one of the fundamental steps of each queen of beauty, but it is often forgotten. It is important to know how to choose sun protection, to better protect yourself from UV rays. To do so in a conscious manner, it is necessary to know how to read the indices of protection. Last week we talked about FPS, the protection factor that indicates how much a sun can protect itself from UVB rays. Today we are dealing with PA, the index to understand how much a sun can protect us from the insidious UVB rays.

Ultraviolet Rays.

As we explained in last week’s All About, ultraviolet (UV) rays are characterized by their specific wavelength. In particular, we distinguish: UVC rays, whose wavelength varies from 100 to 280 nanometers, UVB rays whose wavelength is between 280 and 320 nm and UVA rays with wavelengths from 320 to 400 nm. UVC rays are the most dangerous for human health but fortunately they are filtered out by the ozone layer and therefore do not reach its earth’s surface.

The Radiation from the UVA.

UVA radiation accounts for about 95% of UV radiation and is present equally throughout the year and throughout the day. As mentioned above, UVAs are less energetic than UVBs, because they have a greater wavelength. They contribute less to tanning and the appearance of erythema and sunburn, however, they accelerate the process of skin aging, altering the support fibers of the dermis, elastin and collagen, and contributing to the formation of free radicals.

In turn, UVA radiation is distinguishable in: Short (320-340 nm) and long (340-400 nm) UVAs. The first, more energetic, have always been considered more dangerous and the possible damages have long been investigated. Recently, research has focused more on the possible biological impact of long UVA rays, which account for more than 75% of ultraviolet radiation. These rays, although less energetic, have a greater penetrating power. They are therefore insidious, causing skin damage, especially in the long term. 

As we explained in last week’s All About, ultraviolet (UV) rays are characterized by their specific wavelength. In particular, we distinguish: UVC rays, whose wavelength varies from 100 to 280 nanometers, UVB rays whose wavelength is between 280 and 320 nm and UVA rays with wavelengths from 320 to 400 nm. UVC rays are the most dangerous for human health but fortunately they are filtered out by the ozone layer and therefore do not reach its earth’s surface.

 

 

PPD and PA and Protection from UVA Rays.

As with UVB, there are different levels of UVA protection known as PPD. PPD stands for Persistent Pigment Darkening and PA stands for UVA protection rating and consists of measuring cell colorimeters in vitro, two hours after exposure to the sun. For this reason, the PPD is a variable value and not an objective one, which is why, the European legislation on sun protection has demanded that the value PA is always associated with the value SPF on sunscreens’ labels.

Sun protection with a high PPD offers protection against damage caused by UVA rays, which are the main cause of sun allergies, premature skin ageing, the appearance of pigment spots or sometimes simply imperfections. UVA rays may also increase the risk of developing skin cancers. A sunscreen with a good SPF/PPD ratio offers broad spectrum protection against UV radiation.

In Asia and Europe, PA and PPD are a similar protection parameter to that of SPFs, with the main difference that in the case of PPD and PA we talk about increasing the ability to stay in the sun, protecting ourselves from exposure to UVA and non-UVB rays

The Measurment of PPD and PA.

The PPD is expressed numerically, while the PA is expressed through the + symbol. Here are some examples:

  • Low Protection Solar: PPD from 2 to less than 4 or PA+
  • Solar Medium Protection: PPD from 4 to 8 or PA ++
  • High Protection Solar: PPD from 8 to 16 or PA+++
  • Very High Protection Solar: PPD 16 or higher PA++++

Conclusions.

PPD – PA and SPF are two sides of the same coin: two important indices to know to be able to adequately protect themselves from the radiation of the sun. We cannot repeat it enough: sun protection is always essential, even considering the increase in radiation due to the exacerbation of the phenomenon of global warming. Protect your skin and the skin of your loved ones. Make sure to browse miloon to source the best sunscreen for your skin type needs