Posted on the website on 23 March 2001.
UV Doses of Americans¶
Article first published online: 1 MAY 2007
Photochemistry and Photobiology
Volume 73, Issue 6, pages 621–629, June 2001
How to Cite
Godar, D. E., Wengraitis, S. P., Shreffler, J. and Sliney, D. H. (2001), UV Doses of Americans. Photochemistry and Photobiology, 73: 621–629. doi: 10.1562/0031-8655(2001)0730621UDOA2.0.CO2
- Issue published online: 1 MAY 2007
- Article first published online: 1 MAY 2007
- Revised December 11, 2000; accepted March 20, 2001
The UV doses of Americans were never measured, but are needed for assessing the risks of UV-related health effects. We calculated these doses using a novel approach. The Environmental Protection Agency's (EPA) National Human Activity Pattern Survey (NHAPS) recorded the activity profiles of 9386 Americans over 24 months to assess their exposure to environmental pollutants, one of which is UV radiation. NHAPS used randomized telephone interviews to get their previous day's minute-by-minute activities. From NHAPS we extracted only the outdoor-daylight data of the northern and southern indoor workers (95%), stratifying by season, sex and age (0–21, 22–40, 41–59 and 60+ years) to find the average time Americans spend outdoors. Knowing the total daylight time and that while outdoors Americans are exposed to about 30% of the available solar UV (on a horizontal plane), we calculated their percent ambients. The average American's percent ambients are 2.6 and 2.5% for northern and southern females, respectively, and 3.5 and 3.6% for northern and southern males, respectively. Men over 40 years of age have the highest ambients (4%). From their ambients we calculated their annual doses using seasonal averages of UV measurements taken daily for over 2 years by EPA Brewer spectrophotometers located in four quadrants of the United States: Atlanta, GA; Boston, MA; Bozeman, MT and Riverside, CA. The average erythemal UV doses of Americans are about 25 000 J/m2/year, 22 000 for females and 28 000 for males, or 33 000 J/m2/year including a conservative continental U.S. vacation (7800 J/m2). Thus, we can now assess the risks of UV-related health effects for Americans.