Evaluating the UV Index in Order to Determine Its Relationship to Exposure Level and Health

1. Evaluating the UV Index in Order to Determine Its Relationship to Exposure Level and Health NM HS Supercomputing Challenge 2001 NMT Summer Teacher Institute Team Members: D.B. Gupta Debbie Loftin Dwight Thopmson Beckey Raulie

2. Problem Definition • Although most people know the elevation of the city in which they are living and they take notice of cloud cover at different times of the day, they do not commonly equate this information with a need to alter their behaviors in relation to the incoming solar radiation. • Therefore, we chose to create a simple program that would take this common knowledge and allow it to be input into a program that would give an accurate estimate of the incidence of UVR at the surface for their current location.

3. The Stratosphere Mechanics of Depletion Sunspot Cycle History Lack Of Action Action The Skin and UV Rates of Skin Cancer Types of Research Effects of the Sun Cancer Types Exposure Level Scale Precautionary Measures Understanding SPF Tanning Determining UV Index Variables and Assumptions Our Mathematical Model Results of Our Program Validating Our Model The Gene Introduction

4. The Stratosphere

5. How Is Ozone Depleted? • The main carriers of chlorine are products of the breakdown of CFC’s • HCl and ClONO2 • These eventually percolate up into the stratosp;here where they are broken apart by solar radiation (energy) • the free chlorine atoms interrupt the natural ozone formation by breaking apart O3

6. What is the Role of The Sunspot Cycle? • Every 11 years the sun begins a cycle moving from low to high solar activity (flares, sunspots etc.) • This solar flux significantly changes the ozone concentrations in the stratosphere • cannot be discounted for minor global ozone variations over the past 2 decades

7. History of Ozone Depletion • ~1957 - Canada begins recording surface UVR • 1970 - U.S. Congress cancels SST program* • 1974 - Researchers at UC Irvine project CFC’s serious potential • 1978 - Nimbus 7 satellite • Early 80’s - Agreement in theory that ozone depletion would affect biological cycles disagreement to size of the effect • March 1985-Vienna Convention signed by international community • late 1985 - “Hole” in ozone discovered over Antarctic • Sept 1987 - Montreal Protocol on Substances that Deplete the Ozone Layer • 1990 & 1992- Increased level of emission reduction & reduced timeline • as of 1999 -Canadian Researchers report that average thickness of the ozone layer has declined by ~7% since 1980

8. Reasons for Lack of Action • Industrial scientists • Manufacturers • Historical Data • Industry officials • 1992 Belgian Meteorologist • Models used to predict future ozone depletion • Lack of data for African continent

9. Reasons For Action • Media played on conscience of consumers • Individual convenience contrasted with health of the planet • Belief that actions taken in the present would affect the health of future generations • 1970’s sales of aerosol products dropped to pre-1968 levels • Public support of precautionary principle “err on the side of caution to prevent potential environmental destruction” • Despite problems with instruments and predictive models increasingly sophisticated & accurate measurements of ozone show a downward trend in daily readings

10. The Skin and UV • UVA recently implicated in cutaneous melanoma • Link between UVB and Non-Melanoma Skin Cancer • based on Canadian short term data strong inverse relationship • Detection of long-term changes in UV trends remain difficult • Austria & Switzerland show 7% increase in UVB from 1981-1991 but surface measures in U.S. show a decrease of 8% from 1974-1985 • a European station showed a decrease in UVR when ozone levels were decreased • depends on latitude, cloud cover, surface albedo, tropospheric aerosols, & other pollutants as well as ground level ozone

11. Rates of Skin Cancer • Over the past 40 years the incidence of NMSC & MM have been rising substantially mainly in white populations • Currently mortality may be leveling off likely due to changes in lifestyle & behavioral practices • Western developed countries show greatest increase due to the substantial high risk population • Australia • melanoma in men increased 6.3% annually, but only 2.9% in women between 1959 & 1985 • this has plateaued at the highest levels in the world • Canada • incidence for women decreased -1.0% & has increased for men to 1.5% from 1985-1992 • A 1% decrease in stratospheric ozone results in a 20% increase in NMSC

12. Types of Design in Epidemiological Research • Descriptive Studies • case studies & cross sectional surveys cannont control intervening variables • Analytic Studies • can show direct causal relationship • randomized control trials • Norway no change in ozone • Skin Cancer increases with decreasing latitude • NY 1979-1982 • subgroups without ability top tan & higher moles =higher risk. • Health policy makers have defined skin cancer as a preventable disease under the control of the individual

13. Effects of the Sun • Sunburn • Tanning • Premature Wrinkling • Skin Cancer • Eye Damage • Allergies • Immune System Suppression and Disease

14. Skin Cancer Types

16. Precautionary Measures

17. SPF stands for Sun Protection Factor Example: If you Burn in 10 minutes SPF 8 8 x 10 = 80 minutes SPF 15 15 x 10 = 150 minutes Sunscreeen should be applied 15-30 minutes Before exposure and reapplied after swimming. Waterproof generally means 80 minutes of ‘water resistant’ protection

18. WARNING! Sunblock and sunscreen products are NOT meant to allow a longer exposure time, but to limit the risks of solar exposure.

19. Pigmentation

20. Which is LIGHTER DARKER Better ?

21. Melanin “You have to expose yourself to UV for a short period of time to activate the melanocytes. They produce melanin over the course of hours. By repeating this process over 5 to 7 days pigment builds up in your cells to a level that is protective.” Marshall Brain

22. HowUV Index is Determined • Latitude, Altitude, Time of day (hourly solar zenith angle. • Time of Year (seasonal/vertical ozone profiles) • Orbital Eccentricity • Ozone Conditions • Daily Ozone Values • Cloud Cover (hourly, ceiling height, visibility condition)

23. Variables and Assumptions • Dose values calculated at the top of each hour • local conditions vary on a shorter time scale & solar zenith angle constantly changing • Average incoming UVR takes into account • Ozone absorption seasonally averaged number density profiles at increments of 1km in stratosphere and 0.5km in the troposphere were accurately interpolated to give typical surface-level mixing • TOMS accurately normalized the number density profiles to the total Dobson unit values measured over the region to give seasonal profiles • assumption that aerosol particles (whether natural or anthropogenic) are spherical • SAMSON hourly station observations for 237 locations in the U.S. from 1961-90 correctly infer the type of cloud present, • normalized action spectrum is accurately used • a direct comparison of received dose amts. • erythemal dose

24. Our Mathematical Model • UV INDEX =(290*(1+0.06*D)*E) • UVR range affected by ozone 100 to 315 nm (weighted) • D = Elevation from sea level in Kilometers • UVR increases ~6%/km • E =EXPOSURE LEVEL (cloud cover) • 1 = Clear Skies (100% of UVR) • 2 = Scattered Clouds (89% of UVR) • 3 = Broken Clouds (73% of UVR) • 4 = Overcast (31% of UVR)

25. Validating Our Model • We validated our model by using the example wavelengths given at the EPA site on How to Calculate the UV Index • Our program gave the same results each time

26. Results • Bases on 290 nm overcast skies give the most protection form UV • Incoming UVR only minimally affected by increased elevation

30. References • http://www.nws.noaa.gov/pa/secnews/uv/ • http://www.epa.gov/ozone/uvindex • http://howstuffworks.lycos.com • http://www.mscsmc.ec.gc.ca/uvindex • http://www.rollanet.org/~shady/sunlinks.html • http://www.methodisthealth.com/Skin/ultravio.htm

31. Acknowledgements • Gina Fisk - our sponsoring teacher for helping us to debug our program • Eric Ovaska - for making us feel like we were doing a worthwhile project and the help with Java • Mike Davis - for teaching me how to use gnuplot • Mike Topliff - for allocating more hard drive space for our Powerpoint file. • All of consult for this opportunity to learn all that we did in order to complete this project