by MA. LORNA F. FREZ, MD
THE NEED for sun protection cannot be overemphasized. Sunburn and tanning are common trade-offs for a fun time at the beach or pool. Aside from these immediate effects, end-results of several years of unprotected sun-exposure include skin aging manifesting as wrinkles, blotchy pigmentation and skin sagging. Add to this list the increased risk for developing skin cancer.
The sun’s ultraviolet (UV) rays are responsible for these changes. The UV rays are divided into UVC, UVB and UVA rays.
It is fortunate that UVC rays are filtered off by the stratospheric ozone layer since among these three, it is the most damaging and skin cancer-promoting.
UVB rays which are most intense at mid-day especially during summer are responsible for sunburn and tanning and may also induce skin cancer.
UVA rays are notorious for being the primary sun rays causing skin aging. They can also induce pigmentation. Now, they are also being implicated in the development of skin cancer.
Compared to UVB rays, UVA emissions are more constant throughout the day and seasons of the year. Repeated chronic exposure to these rays will induce significant skin changes.
Making it a habit of avoiding the sun during mid-day by staying indoors or seeking shade from highly reflective surfaces like cemented pavements will go a long way in preventing sun-damaged skin.
Admittedly however, significant daily sun exposures particularly during occupation and recreation-related activities are unavoidable. It is important to note that even during the time of day when the sun seems so harmless with clouds on the sky, the sun’s UV rays are still transmitted.
The use of sun protection aids like clothing, sunglasses, hats, umbrellas and sunscreens are therefore highly encouraged.
Even as more and more people are getting aware of the need for sunscreen use, knowledge on the proper selection and use of these products seems to be lacking.
Choosing a sunscreen is not just a search for one with the highest SPF. After all, SPF, which stands for sun protection factor is a measure limited to a sunscreen’s degree of protection against UVB alone.
It indicates how much longer one can stay under the sun before developing a sunburn (which is a UVB effect) with its use compared to without its use. One also needs to look for UVA protecting sunscreen ingredients.
Sunscreens act by absorbing, reflecting or scattering ultraviolet radiation thereby preventing their absorption by the skin.
The first several sunscreens that were developed were only UVB protective.
Filters with UVA coverage were subsequently introduced. Among them are methyl anthranilate, dioxybenzone, sulisobenzone, oxybenzone, avobenzone or Parsol 1789, titanium dioxide and zinc oxide.
Drometriazole, bemotrizinol and bisoctrizole have been approved in Europe but not in the US.
There is to date no uniformly accepted rating for UVA protection although some are labeled using UVA- PF or PFA or a star system.
Through the years, improvements have been made to increase the efficacy (SPF and spectral coverage), cosmetic acceptability and safety of sunscreen formulations.
It is common practice to combine several UV filters in one product to broaden its spectral coverage as well as to raise protection factors.
The original sunscreen preparations with titanium dioxide and zinc oxide appeared too white on the skin owing to their large particle sizes. Micronization of these particles has made them translucent and therefore more cosmetically appealing.
Another issue is photostability of sunscreens. Some sunscreens or UV filters either alone or in combination are not photostable, i.e., they are inactivated or generate products that may be harmful to the skin upon exposure to sunlight.
New sunscreen formulations may contain sunscreens, which are either intrinsically photostable (or not degraded upon sun exposure) or contain compounds which preserve the stability of filters otherwise known as photostabilizers.
Examples of the latter are diethyhexyl naphthalate (DEHN), dimethicone or silicone coating.
Aside from applying liberally and often a sunscreen, the proper use of sun protection aids like clothing, hats, umbrellas and sunglasses are key factors to prevent sun-damaged skin.
Source: Business World
Hi Sarah...lots of really lovely ideas here...we've been discussing ways of introducing things to the outdoor spaces as well, and I have been thinking about possible ways of illuminating objects, which then can be enjoyed form inside the classroom as well...especially during these darker days.
ReplyDeleteWould be lovely to combine this idea with reflective surfaces....?
I also think that the creation of more intimate and imaginary spaces offer all sorts of possibilities for learning and have been thinking about materials that could be gathered together for a 'dressing up a space' box or basket...?
Projecting images of colour, light and shadow onto an area of painted white wall would also be an interesting startpoint and could form a backdrop/startpoint to the children creating a particular 'place'...an atmospheric landscape of their imagination...
Also quite like the idea of a simple canvas structure/space that could become anything!?
see you tomorrow....Gizella
Since the beginning of this World History class, I learned that the environment affects a community from it's location. The Axum civilization had unpredictable rainfalls and high altitudes. Axum thrived from these conditions because they were able to grow Teff. Teff was a cereal grain that was able to grow through the worst of the weather conditions. I live in West Boylston, MA and there is a pretty predictable rainfall in my community. This is due to the fact that the four seasons of the year (Spring, Summer, Fall, Winter) have pretty predictable weather conditions.
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