We offer a variety of personal UV index monitors and meters for your needs. The UV Index is a standardized scale indicating the intensity of the sun’s UV radiation that affects human skin. (UV can also damage eyes) The UV intensity varies from one place to another, and in the same location it varies throughout the day and as the seasons change. Our watch style monitors (PUVMs) provide wearable technology for real-time UVI monitoring wherever you are…. morning, noon or afternoon.
What Is Ultraviolet Solar Radiation?
Solar Ultraviolet or UV rays make up part of the electromagnetic or photonic spectrum of light and radiant energy. Part of this spectrum is broken down into wavelengths and is measured by nanometers or nm, for short. The electromagnetic spectrum within the wavelength region ranges from the vacuum ultraviolet to the far infrared. We cannot see ultraviolet light and it is shorter in wavelength than visible light. The visible region of the electromagnetic spectrum is approximately the range from 400 to 750 nm in wavelength.
Even though the eye perceives light as one color, the visible region is broken down into the colors of the rainbow: violet, indigo, blue, green yellow, orange, red, measuring in wavelength from 400 to 770 nm.
The ultraviolet region ranges from 10 nm to 400 nm or nanometers and can be further divided into UV-A, UV-B and UV-C. UV-C radiation is in wavelengths less than 280 nm and is extremely dangerous to plants and animals. However, it is absorbed by the ozone layer and does not reach the ground.
More of both UV-B and UV-A rays reach the earth’s surface. UV-B rays range from 280 to 320 nm, and are the primary concern for protection. UV-A rays range from 320 to 400 nm and are somewhat less dangerous.
What Is The Ultraviolet (UV) Index?
The National Weather Service (NWS) and the Environmental Protection Agency (EPA) developed the Ultraviolet or UV Index to help people in planning outdoor activities. The UV Index forecasts the expected intensity of the sun. This forecast should be taken into account when working, playing or exercising during peak periods of sun intensity. Exposure levels are given on a scale of 0 – 10+, with 0 indicating minimal exposure and 10+ indicating very high and dangerous UV levels. You can view the UV Index for major US cities at the National Weather Service site The UV Index does reflect cloud cover and local weather for each region predicted.
What Affects The Intensity Of The UV Index?
The UV Index can vary widely depending on the following factors: time of year or season, time of day, weather conditions, surfaces, altitude and regions of the world, or latitude.
Season, Time of Day and Weather Conditions
The UV Index is higher during the summer months, when the sun’s rays are more direct. The middle of the day, when the sun is highest, has the highest UV exposure. This period can vary from 10 am – 2 PM and changes to 11 am – 3 PM during Daylight Saving. Different cloud cover may block or enhance UV rays. While thick, dark clouds block, puffy or thin-layered clouds do not. Hazy days may see just as high UV reaching the surface as clear days. Some clouds may increase the radiation by reflecting and refracting the sun’s rays.
Elevation or Altitude
At higher altitudes, more UV can get through where the air is clearer and thinner.
Reflective Properties of Surfaces
Bright surfaces can reflect the sun’s rays and increases the UV exposure. Snow, sand, water and concrete will reflect the most UV. Unfortunately, the UV Index cannot take into account incidental reflections. So your skin sees a much higher index than indicated. Contrary to expectations, a snow skiier can be sunburned during the winter while skiing on a mountain slope.
Regions of the World or Latitudes
People living close to the equator, at low latitudes, experience extremely high levels of ultraviolet rays. Countries such as Australia have seen the highest incidence in the world of malignant melanomas, the most serious skin cancer. Countries in South America and Africa are also on or near the equator.
How Are Individuals Affected By The UV Index?
The reaction of an individual’s skin to UV is dependent on several factors: genetics, accumulated exposure and medications.
The Dangers Of UV Exposure
Too much UV-A contributes to photo aging (wrinkles), less severe sunburn, and cataracts. Some studies also link cumulative UV-A overexposure with skin cancer.
While humans need UV-B irradiance to synthesize Vitamin D3, overexposure does not produce additional D3 as the body self-regulates and limits it naturally. UV-B is also responsible for skin reddening (erythema sunburn), and long term cumulative overexposure effects can include skin cancer, cataracts and immune system suppression.
UV-B rays are considerably stronger during the midday hours, but UV-A rays are fairly equal in intensity throughout the day. UV-B intensity influences the UV Index reading the most.
Reducing The Risks Of Overexposure To Ultraviolet Rays
According to the Environmental Protection Agency (EPA) and other government agencies and private organizations, there are ways to reduce the risk of short and long term damage to your skin and eyes:
- Avoid midday sun
- Stay inside when UV Index is high or very high
Sunscreen or sun block lotions are designed to give a certain amount of protection from the sun’s rays. Skin Protection Factor (SPF) describes the increased allowable time of sun exposure before sun burns can occur. For example, SPF 15 means one can stay out in the sun 15 times longer than without sunscreen. The Environmental Protection Agency (EPA) recommends using a minimum SPF of 15.
In addition, the EPA recommends wearing sunglasses, hat and clothing. Sunglasses should block 99 to 100% of UV radiation. If the index is high or very high, it may be best to stay inside.
Personal UV Monitor User Manual
Click [HERE] to download and print our User Manual.