1) The study examines the doses of ambient UVA radiation received by different anatomical zones during typical outdoor leisure activities. 2) Ratios of UVA radiation received by different body parts were determined for a standard mix of leisure activities like tennis, swimming, and walking. The foot receives up to 60% of ambient UVA radiation. 3) A relationship was established between daily UVA and UV erythemal doses measured in the French Riviera, allowing the calculation of absolute UVA doses from the erythemal dose. For a sunny day with a 20 MED erythemal dose, the estimated outdoor UVA dose is 125 J/cm2, and the foot would receive up to 75 J/

1. WHICH DOSE OF AMBIENT
UVA RADIATIONS DO WE RECEIVE?
P-371 F. J. Christiaens 1, A. M. Chardon 2, A. Fourtanier 1.
1 Life Sciences, L’ORÉAL Advanced Research Laboratories, Clichy, FRANCE.
2 L’ORÉAL, Applied Research and Development, Clichy, FRANCE.
INTRODUCTION MATERIAL AND METHODS
UVA exposure induces skin damage. To date, few data are The human body area has been divided in nine zones.
available on anatomical distribution of UV doses received daily. Personal dosimetry of solar UV radiation for different outdoor activities was achieved
Most of them are linked to erythemally effective UV doses; None by E. Herlihy et al. 1, Holman et al. 2 . Dosimetry was also performed on manikins 3.
was found related to UVA radiations.
The aim of this work was to establish the dose of ambient UVA In our study, the following hypothesis were made:
rays received by different anatomical zones during a 1.The solar UV angular distribution is identical for UVB and UVA.
representative day of outdoor leisure activities. 2. The albedo is supposed to be the same for UVB and UVA wavebands. Thus, the
same proportion of UV radiations is assumed to be reflected for both wavebands,
whatever the orientation of the dosimeter is.
As a consequence, data obtained using polysulphone films were considered correct
for estimating the proportion of received UVA radiations.
Only outdoor activities were considered. A ‘standard’ leisure activity was defined by
calculating the average of the proportions calculated for the following activities:
tennis, sailing, swimming, walking, golf, gardening and sunbathing. When results from
measures made on humans were not available, measurements made on manikins
were taken. Fractions have been rounded to the closer 0- or 5-ending number.
To calculate ‘absolute’ UVA doses (units: J/cm 2), the
following method has been applied:
• Both erythemal (UVe) and UVA irradiances were
measured, using two Solar-Light Biometer 501
detectors (Figure 1) located in the French Riviera.
• Corresponding daily doses have been calculated
(Figures 3 and 4).
• Daily UVA doses versus daily UVe doses have been
plotted for days comprised between April 1st and
October 31 s t, when outdoor temperature may
Synopsis of this poster. allow leisure occupational activities (Figure 5). Figure 1
RESULTS
The proportions of ambient UVA radiations received during the standard leisure outdoor occupational activity are shown on Figure 2.
Figure 3: Daily UVe doses, French Riviera.
Figure 2: Anatomical distribution of ratios of ambient UVA radiations Figure 4: Daily UVA doses, French Riviera.
A relationship between daily UVA and UVe doses has been established, that
allows the calculation daily UVA dose. The best fit and the 95% upper and lower
confidence level curves for predicted values have been plotted on Figure 5.
For the French Riviera, the relationship between daily UVA and UVe doses is
given by the equation:
UVA dose (J/cm2) = 10.79 x (erythemal UV dose)0.82
For instance, for a clear sunny day (20 MED): Outdoor ambient UVA dose:
10.79 x (20) 0.82 = 125 J/cm2
For the standard leisure activity described here, the foot may receive up to:
125 J/cm2 x 60% = 75 J/cm2 .
These data can be used to estimate the UVA protection level needed on the
basis of action spectra and individual biological thresholds. Figure 5: Correlation between daily outdoor UVe and UVA doses,
French Riviera, Apr.-Oct.
LIMITS
• For a given anatomical site, wide differences exist, depending on the activity. If different occupational activities are addressed, then calculations may
need to be adapted.
• As pointed out by Diffey et al. 4, the extrapolation of results for a given location to another location may not be appropriate where the culture or the
solar environment are substantially different.
• Only outdoor activities have been addressed. The main portion of UVA radiation passes through standard glass, thus high UVA doses may be received
during indoor activities. As results were derived from measures in erythemal units, they cannot be applied to any activity involving a long indoor stay.
Additional research is required to correctly address the absolute doses of UVA radiations received either outdoor or indoor.
CONCLUSIONS
• Rough ratios of ambient UVA rays that we receive during a standard leisure occupational activity have been determined.
• A method to estimate the absolute level of UVA doses received outdoor has been suggested.
• These data may be useful to define the adequate level of UVA protection that sunscreens should provide, according to consumer habits.
REFERENCES
1.Herlihy E, Gies PH, Roy CR, Jones M. Personal dosimetry of solar ultraviolet radiation for different outdoor activities. Photochem Photobiol 1994;60:288-94.
2.Holman CDJ, Gibson IM, Stephenson M, Armstrong BK. UV irradiation of human body sites in relation to occupation and outdoor activity: field studies using personal UVR dosimeters. Clin Exp Dermatol 1983;8:269-77.
3. Diffey BL, Kerwin M, Davis A. The anatomical distribution of sunlight. Br J Dermatol 1977;97:407-10.
4. Diffey BL, Gibson CJ, Haylock R, McKinlay AF. Outdoor UV exposure of children and adolescents. Br J Dermatol 1996;134:1030-4.
ACKNOWLEDGEMENTS: The 100t h annual meeting.
We thank R.Mascotto for critical reading and helpful discussions. The Japanese Dermatological Association, Tokyo 2001