Activity 1: Using the UV Index

An ultraviolet radiation index has been developed by the National Weather Service and the Environmental Protection Agency (EPA). This UV Index gives the UVB radiation level forecast for 58 cities in the United States. We can use this index to plan safe outdoor time for ourselves and our children.

Read this first!!

Here is a description of the UV Index

It tells what the UV Index numbers mean. It also suggests simple sun safety tips. You may want to print a copy of this information for later use.

The UV forecast varies from city to city, depending on the city's place on Earth and its elevation above sea level. We can find the forecasts on a map and/or a table provided by the National Oceanic and Atmospheric Administration.

a. table: http://www.cpc.ncep.noaa.gov/products/stratosphere/uv_index/bulletin.txt

b. map: http://www.cpc.ncep.noaa.gov/products/stratosphere/uv_index/uvi_map.gif

1. Find the UV forecast for your part of the United States.

Which city on the index is closest to you?_____________________________

What number on the UV Index has been forecast for today? ______________

2. So, what does that mean? Are you at risk of high UVB radiation today? Describe what you should do if you are going to be outside today.

UV Index (same as above) http://www.epa.gov/sunwise1/uvindex/uvwhat.html

Action Steps for Sun Protection: http://www.epa.gov/ozone/uvindex/uvaction.html

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3. The UV Index gives a general idea of the time it will take for the average person to get a sunburn from UVB radiation. However, an individual person may be more or less likely than average to get a burn. So, find out your own personal "minutes to skin damage" by using the "Burn Frequency Chart". (You may want to print a copy of this chart for later use)

In order to use this chart, you need to know what kind of information is presented. The labels on a chart or graph tell you what is being measured.

• What is the label for the the x-axis? (the x-axis is the horizontal line along the bottom of the chart) __________________________
• What is the label for the y-axis (the y-axis is the vertical line along the left side of the chart) __________________________
• The colored bars in the center of the chart show the "Burn Frequency": rarely--sometimes---usually---always. How often do you get a sunburn when you are exposed to the sun? __________________________

Now, what is today's UV Index number for your area?_____________

• Find that number on the x-axis along the bottom of the chart.
• Find the section above that number for your "Burn Frequency": rarely--sometimes--usually--always.
• With your finger, draw an imaginary line from that section toward the left edge of the chart (the y-axis). The place where your finger hits the y-axis shows the range of minutes you can safely be outside before you are likely to burn.

What is your "Minutes to Skin Damage" time range for today?________________

Written by Susan K. Cowles, Oregon Weather Project, OASIS, 1998

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