Earth Gauge » UV

Sunlight and Sleep

administrator — Mon, 10 Aug 2009 12:28:44 +0000

Did you know that most humans would operate on a 25-hour cycle without exposure to sunlight? Instead, we operate on a 24-hour cycle, following the 24-hour cycle of the sun. Humans are “diurnal” animals, sleeping during the night and being active during the day, as opposed to “nocturnal” animals which are active at night. When sunlight reaches our eyes, it alerts our “biological clock,” a region of the brain that sends signals to other areas of the brain, that it’s time to wake-up. Body temperature rises, urine production and blood pressure increase, and hormone secretions change to get us ready to start the day.

Viewer Tip: Exposure to sunlight plays a powerful role in human sleep cycles. Sleep experts recommend waking up to sunlight or bright light when possible to help your body reset its biological clock each day. Getting outdoors for an hour of sunlight in the morning can also help your body regulate its sleep cycle, and seeking sunlight in the morning can help jet-lagged travelers adjust their sleep schedules.

Seasons: Spring, Summer, Fall, Winter

(Sources: National Institute of Neurological Disorders and Stroke, National Institutes of Health. “Brain Basics: Understanding Sleep.” http://www.ninds.nih.gov/disorders/brain_basics/understanding_sleep.htm; Harvard Medical School and WGBH Educational Foundation. “Healthy Sleep.” http://healthysleep.med.harvard.edu/healthy/; Capital Weather Gang, The Washington Post. “Sleeping Through Sunlight: Not a Success.” http://voices.washingtonpost.com/capitalweathergang/2009/08/sleeping_through_sunlight_not.html)

Cool Critters

administrator — Fri, 17 Jul 2009 15:37:12 +0000

Have you ever wondered how animals stay cool when the weather heats up? Check out these creative ways to beat the heat:

Pelicans, cormorants and other birds create “internal fans” by rapidly fluttering their throat pouches.
Pigs wallow in mud to cool off – evaporative cooling occurs as the mud dries; mud also protects pigs’ skin from the sun.
Sea lions float in the water like rafts, holding their flippers up. Blood vessels that are just underneath the skin dilate to release heat.
Burrowing owls escape the hot sun by seeking shelter in underground burrows that they build or borrow from other animals, such as armadillos, tortoises or prairie dogs.

Viewer Tip: Many animals sleep or rest in the shade during the hottest part of the day and increase their activity during the evening, night and early morning hours. You can beat the heat by following their lead – minimize time spent outdoors during the hottest part of the day and save intensive outdoor sports and gardening activities for the evening or early morning hours. When you do spend time outside, seek shade and apply sunscreen regularly.

Season: Summer

(Sources: SeaWorld, Busch Gardens, Discovery Cove and the Conservation Fund. “Wild Ways to Stay Cool,” Wildlife, July 2009. http://www.swbg-animals.org/wildlife/2009/jul/index.htm?src=2009WODsilverpopWildlifeJulyRATM; University of Minnesota Extension. “Minimizing Heat Stress in Pigs During the Summer.” http://www.extension.umn.edu/swine/components/pubs/Whitney-MinimizingHeatStress.pdf; “California Sea Lion.” http://www.seaworld.org/animal-info/info-books/california-sea-lion/adaptations.htm)

Don’t Fry Day

administrator — Thu, 21 May 2009 17:54:38 +0000

As the temperature goes up, so does the potential for getting sunburnt. Did you know that one in five people will get skin cancer, often from the sun’s rays? The good news is that skin cancer is preventable.

Viewer Tip: The Friday before Memorial Day (May 22) is Don’t Fry Day. The National Council on Skin Cancer Prevention and EPA provide these tips so you can enjoy the outdoors safely:

Slip on a shirt;
Slop on some sunscreen;
Slap on a wide-brimmed hat;
Wrap on some sunglasses.

Check your local forecast for the UV Index, and have fun in the shade between the hours of 10 a.m. and 4 p.m. Find other tips and free resources at www.skincancerprevention.org.

Seasons: Spring, Summer

This information is provided by the U.S. Environmental Protection Agency’s SunWise Program and the National Council on Skin Cancer Prevention.

UV-Aware

administrator — Wed, 30 Jul 2008 15:57:29 +0000

Ultraviolet (UV) radiation from the sun causes sunburn and other health effects, including skin cancer and cataracts. Everyone should protect themselves from the sun, and some groups can be particularly susceptible to health effects from sun exposure:

Kids: About 25 percent of a person’s lifetime exposure to UV radiation occurs before the age of 18, meaning that it is especially important to protect children – who may not know how to properly protect themselves – from sun exposure.
Gardeners and Farmers: The National Gardening Association found that the average gardener spends 2.8 hours per week in the garden. Because they spend lots of time outside, gardeners and farmers can be more at-risk for skin cancer.
Older Individuals: Older people’s skin cells are less able to repair DNA damage caused by exposure to the sun. There is also evidence that UV-B radiation from the sun puts older people at increased risk of developing cataracts.

Viewer Tip: When possible, work and play outside during the cooler parts of the day – before 10:00 a.m. and after 4:00 p.m. – and remember that it is possible to burn on a cloudy day, even when the sun doesn’t seem bright. Use a sunscreen with a Sun Protection Factor (SPF) of at least 15 that provides protection from both UVA and UVB rays. Apply sunscreen liberally and often, and wear protective clothing – hat, sunglasses, long-sleeved shirt, and pants.

Added Bonus: Gardening in the early morning or evening is better for your plants, too! Water evaporates more quickly in the sun, so watering during the cooler parts of the day means your plants retain more water. Transplants will also fare better if performed during cooler parts of the day, when there is less stress from the sun’s heat.

Seasons: Spring, Summer

(Sources: The Skin Cancer Foundation. “Sage Advice.” http://www.skincancer.org/sunscreen/sage-advice.html; Fosdick, Dean (Associated Press), July 9, 2008. “A Growing Problem.” The Washington Post Express; U.S. EPA Aging Initiative. “UV Radiation and Health Effects.” http://www.epa.gov/aging/resources/climatechange/uv-radiation.htm; U.S. EPA Office of Air and Radiation. September 2006. “The Sun, UV, and You: A Guide to Sunwise Behavior.” http://www.epa.gov/sunwise/doc/sunuvu.pdf)

UV Awareness

administrator — Wed, 30 Jul 2008 15:48:36 +0000

Ultraviolet (UV) radiation causes sunburn and other health effects, including skin cancer and cataracts. There are a number of factors that affect how much UV light reaches the earth’s surface.

Stratospheric Ozone: The stratospheric ozone layer (between six and 30 miles above the earth’s surface) absorbs much of the UV radiation from the sun. However, the ozone layer thickness varies by region, time of year, and weather patterns. A thinner ozone layer lets more UV radiation through.
Time of Day: Around noon, the sun is highest in the sky, meaning that UV rays have a shorter distance to travel through the atmosphere. UV levels are highest around noon, and less intense in the early morning and late afternoon.
Time of Year: Because the angle of the sun varies with the seasons, UV intensity also varies. Intensity tends to be highest during the summer months.
Latitude: The sun is strongest near the equator, where it is directly overhead and UV rays have a shorter distance to travel to reach the earth. At higher latitudes, the sun is lower in the sky and UV rays must travel a longer distance, meaning these areas are generally exposed to lower levels of UV radiation. The ozone layer also tends to be thinner at the equator than at higher latitudes.
Altitude: Higher altitude means there is less atmosphere to absorb UV rays and UV intensity is higher.
Weather: Cloud cover does reduce UV levels, but not completely. It is possible to burn on a cloudy day, even if the sun doesn’t seem bright.

Viewer Tip: Everyone should protect themselves from the sun, and it is especially important to protect children from UV exposure. About 25 percent of a person’s lifetime exposure to UV radiation occurs before the age of 18! Choose a sunscreen with a Sun Protection Factor (SPF) of at least 15 that provides protection from both UVA and UVB rays. Apply sunscreen liberally and often, and wear protective clothing – hat, sunglasses, long-sleeved shirt, and pants when possible.

Season: Summer

(Sources: U.S. EPA Office of Air and Radiation. September 2006. “The Sun, UV, and You: A Guide to Sunwise Behavior.” http://www.epa.gov/sunwise/doc/sunuvu.pdf)

UV-Wise

administrator — Tue, 22 Jul 2008 18:59:37 +0000

This is the time of year when Americans begin spending more time outside, increasing their exposure to the sun. The stratospheric ozone layer (a protective layer of “good” ozone about six to 30 miles above the earth’s surface) absorbs many of the sun’s harmful UV (ultraviolet) rays. However, depending on the time of year, weather, and exposure to ozone-depleting compounds, the thickness of the ozone layer can vary, letting more UV radiation through in some areas. There are three types of UV radiation: UVA, which is not absorbed by the ozone layer; UVB, which is partly absorbed by the ozone layer; and UVC, which is absorbed completely by the ozone layer and oxygen in the atmosphere. Becase UVA and UVB rays reach the earth, they can penetrate our skin and eyes, causing adverse health effects – sunburn, skin cancer and other skin conditions, cataracts, etc.

Viewer Tip: Just five or more sunburns can double your risk of developing skin cancer, meaning that it is especially important to take protective steps. Apply sunscreen to exposed skin, and use at least SPF 15, with broad-spectrum coverage that protects against both UVA and UVB rays. If you will be near water, snow, or sand, remember that these surfaces reflect light and can increase your chance of burning. Before you head outside, check the UV Forecast for your area at the EPA SunWise website: www.epa.gov/sunwise/uvindex.html#map.

Season: Spring

(Sources: US Environmental Protection Agency, Office of Air and Radiation. “The Sun, UV and You: A Guide to SunWise Behavior.” http://www.epa.gov/sunwise/doc/sunuvu.pdf)

UV-Beware

administrator — Mon, 23 Jul 2007 19:06:58 +0000

We all know that the sun’s UV rays can be harmful to humans – but did you know that the sun can also damage plants? Damaging UV-B rays can affect crop growth, make some plants more susceptible to disease, and even change plant coloring.

Viewer Tip: Although scientists are still learning about how to protect plants from damaging sun rays, we already know a lot about how to protect ourselves. Please remember to protect yourself in the sun: cover up and use sunscreen, try to stay in the shade, and remember that the sun is strongest during midday hours – 10am to 4pm.

Seasons: Summer

(Sources: The USDA UV-B Monitoring and Research Program: http://uvb.nrel.colostate.edu; US EPA. 2004. “A Guide to the UV Index.” Brochure. )

UV Aware

administrator — Mon, 23 Jul 2007 18:59:01 +0000

Although a heavy cloud cover can block some of the sun’s UV rays, which can damage skin and cause sunburn, thin or broken clouds still allow most UV rays through! Puffy “fair-weather” clouds can actually increase UV radiation reaching the Earth’s surface by deflecting the rays.

Viewer Tip: Take precautions to protect yourself from the sun. Cover up and use sunscreen and remember that the sun is strongest during midday hours of 10am to 4pm. If you can, try to stay in the shade – while trees do not provide complete protection from the sun, staying in their shade can protect you from about 60 percent of the sun’s rays.

Seasons: Spring, Summer, Fall, Winter

(Sources: US EPA. 2004. “A Guide to the UV Index.” Brochure. www.epa.gov; National Safety Council, www.nsc.org)

Understanding UV

administrator — Mon, 23 Jul 2007 18:45:14 +0000

Did you know that many factors affect the intensity of the sun’s damaging UV rays that reach the earth’s surfaceCloud cover can affect the amount of UV radiation reaching the earth, and land cover, such as buildings and trees, can actually reduce exposure to UV radiation. Even time of day is important – UV peaks during midday, when the sun is highest in the sky.

Viewer Tip: Always practice sun safety when spending time outdoors. Be sure to wear sunscreen and sunglasses! And remember, staying in the shade and covering up are the best protection from UV rays.

Seasons: Spring, Summer, Fall

(Source: US Environmental Protection Agency. 2004. “A Guide to the UV Index.”)

Sunburned Plants?

administrator — Fri, 20 Jul 2007 20:38:55 +0000

It’s clear that the sun’s ultraviolet (UV) rays are damaging to humans, but did you know that sun exposure can also be damaging to plants and wildlife? Scientists have found that some plants – including native forest, grassland, and marine species – have smaller leaves or grow less when they are exposed to UV, and exposure may make them more prone to disease. Studies have also found that amphibians, such as salamanders, are more likely to have deformities or lower hatching rates when exposed to UV light.

Viewer Tip: While scientists are still learning about how to protect sensitive plants and animals from sun exposure, we do know how to protect ourselves! Cover up; wear sunscreen, sunglasses, and a hat; and stay in the shade while you’re outside to reduce your exposure.

Season: Summer

(Source: University of Colorado and NOAA’s Air Resources Laboratory in collaboration with the National Parks Service and PRIMENet. “UV and Plants,” and “UV and Amphibians.” Available from http://www.srrb.noaa.gov/UV/)

Sun Sense

administrator — Fri, 20 Jul 2007 20:36:46 +0000

Even though depletion of “good” ozone in the stratosphere is being reduced, loss of this protective layer over the earth can still allow increased amounts of UV rays from the sun to reach the Earth. Not only are UV rays attributed to cases of skin cancer and cataracts, but they can also damage sensitive plant life, such as soybeans and tiny marine phytoplankton (microscopic marine plants that are very important to the ocean food chain).

Viewer Tip: Although scientists are still learning about how to protect plants from damaging sun rays, we already know a lot about how to protect ourselves! Sunburn can occur even on cooler days — please remember to protect yourself in the sun. Cover up and use sunscreen, try to stay in the shade, and remember that the sun is strongest during midday hours – 10am to 4pm.

Season: Summer

(Sources: US. EPA. 2003. “Ozone: Good Up High, Bad Nearby.” Brochure; The USDA UV-B Monitoring and Research Program: http://uvb.nrel.colostate.edu ; US EPA. 2004. “A Guide to the UV Index.” Brochure. )

Cloud Cover

administrator — Thu, 19 Jul 2007 16:53:44 +0000

Although heavy cloud cover can block some of the sun’s UV rays, which can damage skin and cause sunburn, thin or broken clouds still allow most UV rays through! Puffy “fair-weather” clouds can actually increase UV radiation reaching the Earth’s surface by deflecting the rays. UV rays can also be damaging to plants and animals.

Viewer Tip: Even on a cloudy day, remember to take precautions to protect yourself from the sun. Cover up and use sunscreen, stay in the shade, and remember that the sun is strongest during midday.

Seasons: Summer

(Source: US EPA. 2004. “A Guide to the UV Index.” Brochure. )