Sunscreen vs Sunblock, Which Suits Us More ?

There are two types of protective lotions – chemical and physical.

   

Sunblock, the physical kind, contains both organic and non-organic ingredients that sit on top of the skin acting as a barrier between your skin and damaging UV rays by reflecting or scattering UVB light. Look for products with octyl methoxycinnamate, octyl salicylate and octocrylene. In the past, you could tell who was using a sunblock just by looking, because the sunblock whited out the skin. Not all modern sunblocks are visible because the oxide particles are smaller, though you can still find the traditional white zinc oxide. 

Sunscreen, the chemical kind, penetrates the skin and absorbs the UVA rays before they are able to reach and damage your dermal layer. Like a screen door, some light penetrates, but not as much as if the door wasn't present. Zinc oxide and titanium dioxide are the active ingredients in deflecting harmful UV rays before they reach the protective outer epidermis layer of your skin. Another ingredient to look for is ecamsule, which is a photostable sun protectant that blocks out photoaging UVA rays. 

Sunblocks are formulated to shield against UVB rays, while sunscreens protect against UVA. In order to fully protect your skin, choose a broad-spectrum protection formulated sunscreen that will protect against both UVA and UVB rays (The “A” in UVA stands for ‘Aging’. The “B” in UVB stands for ‘Burning’). Luckily these days, formulas often contain a mixture of both sunblock and sunscreen.

What Sunscreens Screen ?

• UV-A penetrates deeply into the skin and can lead to cancer and premature skin aging.
• UV-B is involved in tanning and burning of your skin.
• UV-C is completely absorbed by the earth's atmosphere.
• PABA (para-aminobenzoic acid) absorbs UVB
• Cinnamates absorb UVB
• Benzophenones absorb UVA
• Anthranilates absorb UVA and UVB
• Ecamsules absorb UVA

What SPF Means ?

The portion of the sunlight that is filtered or blocked is ultraviolet radiation. There are three regions of ultraviolet light.

The organic molecules in sunscreen absorb the ultraviolet radiation and release it as heat.

SPF stands for Sun Protection Factor. It's a number that you can use to help determine how long you can stay in the sun before getting a sunburn. Since sunburns are caused by UV-B radiation, SPF does not indicate protection from UV-A, which can cause cancer and premature aging of the skin.

Your skin has a natural SPF, partially determined by how much melanin you have, or how darkly pigmented your skin is. The SPF is a multiplication factor. If you can stay out in the sun 15 minutes before burning,using a sunscreen with an SPF of 10 would allow you to resist the burn for 10x longer or 150 minutes.

Although the SPF only applies to UV-B, the labels of most products indicate if they offer broad spectrum protection, which is some indication of whether or not they work against UV-A radiation. The particles in sunblock reflect both UV-A and UV-B.

         

To Reapply or Not to Reapply?

Consider your personal needs and habits when deciding the best sun protectant. You may also need to consider your application depending on activity level. For instance, if you’ll be in the water or sweating a lot, it is best to reapply frequently. Sensitive skin may fare better with sunblock since titanium dioxide and zinc oxide are less irritating than some ingredients found in sunscreen.

Adding sunscreen to your daily routine can block UVA, promoting graceful aging and UVB, which can keep your skin from burning. With this new knowledge you can safely minimize your sun exposure risk and choose the right sunblock to best fit your lifestyle.

Is there a difference between "waterproof" and "water-resistant" ?

How well the sunscreen stays on the skin after swimming, bathing or perspiring is just as important as the SPF level. The FDA considers a product "water-resistant" if it maintains its SPF level after 40 minutes of water exposure. A product is considered "waterproof" if it maintains its SPF level following 80 minutes of exposure to water. If you participate in outdoor recreational activities including swimming, you may want to choose a waterproof sunscreen.

The Bottom Line on Sunblock vs Sunscreen:

1. Most lotion is a combination of both sunblock and sunscreen, so read the ingredients carefully if you are needing a pure sunblock.

2. Be sure to look for a sunblock or sunscreen that does NOT contain vitamin A and its derivatives, retinol and retinyl palmitate, as this may speed up the cancer that sunscreen is used to prevent.

3. Be sure to check the Environmental Working Group’s searchable database of all sunblocks and sunscreens before headed to the store to find the ones safest and most effective for you and your family.

WILL ONE BAD APPLE RUIN THEM ALL ?

You've heard that 'one bad apple spoils the whole barrel', right? It's true. Bruised, damaged, or overripe fruit gives off a hormone that accelerates the ripening of the other fruit -- ETHYLENE.

What is ETHYLENE ?

Ethylene (C2H4, also known as ethene) is a gaseous organic compound that is the simplest of the alkene chemical structures (alkenes contain a carbon-carbon double bond).  Ethylene is the most commercially produced organic compound in the world and is used in many industrial applications. 

Plant tissues communicate by means of hormones. Hormones are chemicals that are produced in one location that have an effect on cells in a different location. Ethylene is the hormone that will cause a wide range of effects in plants, such as fruit ripening, loss of chlorophyll, abortion of plant parts, stem shortening, abscission of plant parts, and epinasty (bending of stems) which  depending on the age of the plant and how sensitive the plant is to ethylene. Ethylene can be either good or bad, depending on what merchandise you work with. It is used in a positive manner in fruit ripening, for instance. It can also cause damage in crops. Examples of damage might include yellowing of vegetables, bud damage in dormant nursery stock, or abscission in ornamentals (leaves, flowers drop off). Most plant hormones are transported through the plant vascular system, but some, like ethylene, are released into the gaseous phase, or air.

                                         

Where does it come from?

Ethylene is produced and released by rapidly-growing plant tissues. It is released by the growing tips of roots, flowers, damaged tissue, and ripening fruit. The hormone has multiple effects on plants. One is fruit ripening. When fruit ripens, the starch in the fleshy part of the fruit is converted to sugar. The sweeter fruit is more attractive to animals, so they will eat it and disperse the seeds. Ethylene initiates the reaction in which the starch is converted into sugar.

Commercial Use of Ethylene to Ripen Fruit

Climacteric fruits are frequently harvested at a physiological stage that is considered ‘commercial maturity’, typically in a hard green but mature stage just before ripening has initiated.  Examples include bananas, mangoes, tomatoes and avocados.  This enables the fruit to be harvested, cooled, stored and transported significant distances to where it will be marketed and consumed.

Ripening can then be conducted under controlled conditions of temperature, relative humidity and ethylene to achieve uniform appearance and quality of ripe fruit.  Fruit is placed into specially constructed ripening rooms and brought to optimum ripening temperature and humidity.  Ethylene is then raised to a prescribed concentration using either a "catalytic generator" that makes ethylene gas from liquid ethanol or from commercially available gas supplies.  Forced-air cooling systems ensure that fruit are uniformly exposed to the room ethylene concentration.  When fruit are exposed to ethylene under these controlled conditions they will initiate their respiratory climacteric pattern and ripen at a relatively uniform rate.  Conditions and duration can be varied to suit customer specifications for stage of ripening and colour development.

However, concerns are periodically raised in mass media about fruit being ‘gassed’, implying that this confers some residual food safety risk from the ethylene gas and that the fruit has been somehow rendered ‘unnatural’.  The public should understand that the commercial use of ethylene for fruit ripening is at a low concentration and simply initiates the respiratory climacteric.  The ethylene used commercially has the same molecular structure.  By the time the ethylene-treated fruit reaches the consumer the climacteric may have started, there is no trace of applied ethylene gas, any ethylene emitted by the fruit is generated by the fruit itself and is of a much greater concentration.  Therefore, there are no food safety issues associated with the consumption of climacteric fruit.