Ultraviolet Rays

UV rays penetrate the atmosphere even if it is cold or cloudy (these are not associated with the heat derived from the sun - as this is due to infrared light). The rays are more intense between 11:00 and 4:00. UV strength and reflection from water is 5%, sand 20%, grass 5% and snow is especially high at 85%.

Health effects of UV radiation

Small amounts of UV are beneficial for people and essential in the production of vitamin D. UV radiation is also used to treat several diseases, including rickets, psoriasis, eczema and jaundice.

Prolonged human exposure to solar UV radiation may result in acute and chronic health effects on the skin, eye and immune system.

It is important to note that 90% of UV rays can reach the retina of babies.

UV Index

The ultraviolet index or UV Index is an international standard measurement of the strength of the ultraviolet (UV) radiation from the sun at a particular place on a particular day and identifies the health risks associated with the measurement.

There are 5 categories of UV index each corresponding to a level of risk:

• 1- 2 Low: Wear sunglasses on bright days.

• 3 – 5 Moderate: Take precaution by covering up, and wearing a hat, sunglasses and sunscreen, especially if you will be outside for 30 minutes or more. Look for shade near midday when the sun is strongest.

• 6 – 7 High: Reduce time in the sun between 11 a.m. and 4 p.m. and take full precaution by seeking shade, covering up exposed skin, wearing a hat and sunglasses, and applying sunscreen.

• 8 – 10 Very High: Extra precaution required - unprotected skin will be damaged and can burn quickly. Avoid the sun between 12 a.m. and 4 p.m. and seek shade, cover up, and wear a hat, sunglasses and sunscreen with a very high protection factor (50+).

• 11+ Extreme: Take full precaution. Unprotected skin will be damaged and can burn in minutes. Avoid the sun if possible. If not possible, cover up, and wear a hat, sunglasses and sunscreen with a very high protection factor (50+).

Difference between UVA and UVB

UVA rays penetrate the deep layers of the skin. They induce an immediate bronzing effect and cause premature aging of the skin. They can also provoke skin cancer.

UVB rays cause sunburns, inflammation, premature aging and skin cancer. Certain studies indicate that the benefits of short term exposure to these rays (10 minutes a few times per week) outweigh the risks.

Sun-safety tips

Before heading outside, it is important to protect yourself from the risks associated with prolonged sun exposure. Some simple sun-safety tips include:

• Check for the UV index of the day - if it is 3 or higher, don't leave the house without your sunglasses, sunscreen and a wide-brimmed hat.

• Apply sunscreen of SPF 15 or higher to all exposed skin 20 minutes before going outside and reapply every two hours (more often if you are swimming or sweating).

• Limit exposure to the sun between 11 a.m. and 4 p.m., when the sun rays are the strongest.

• Be aware that certain medications can make your skin more sensitive to UV rays. (talk to your doctor).

• Don’t forget your lips, ears and nose. These parts of your body burn especially easily.

• Stay hydrated, wear light, loose fitting clothing and slow down - remember that summer is for relaxing!

• Seek shade under a shelter, a gazebo or an umbrella.

Have a safe and happy summer !