Hello everyone. There is a LOT of controversy surrounding UV-radiation power that is considered hazardous, so I decided to estimate it myself based on assumption: people do not get a hazardous level of UV light during 10 minute outdoor July-month walking in middle Europe.
Let's go.
https://www.ncbi.nlm.nih.gov/books/NBK401584/
In that paper we have estimation of 5% of sun light power at ocean level (below atmosphere) is UV light.
See picture in next post from EU PHOTOVOLTAIC GEOGRAPHICAL INFORMATION SYSTEM where we have daily irradiance of 672 W/m2 somewhere in Poland at 11:00 o'clock.
Okay, so we got UV part equal 0.05 * 672 = 33.6 W/m2
Now let's consider human body open parts as 20% of all body surface area which is approx. 1.90 m2 according to Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317:1098 and divide it by two because we have sun lighting from one direction, not everywhere.
So we got 0.2 * 1.9 * 0.5 = 0.19 m2.
So power of UV-radiation exposure is 33.6 * 0.19 = 6.4 W.
BUT take a look at datasheet of typical UV LED https://www.mouser.fr/datasheet/2/50/UV3TZ-XXX-XX-881014.pdf
so here we have 10mW and in general you can find something from 1 mW to 100 mW, but them almost by any resource (including manufacturers) named dangerous (cancer-inducing, wear protection and so on).
Also I have an mercury lamp which is highly dangerous according to its manual, it has 1 W/m2 power.
Energy of Sun MUCH greater and someone is really wrong here, maybe me? Appreciate your answer.
P.S.: I have a clue: maybe it is our eyes are much more susceptible for UV-radiation than skin and all of that based on danger for eye vision, but on the contrary we have a lot of reflecting surfaces on sunny day which may return us to a problem in numbers I have here.
Let's go.
https://www.ncbi.nlm.nih.gov/books/NBK401584/
In that paper we have estimation of 5% of sun light power at ocean level (below atmosphere) is UV light.
See picture in next post from EU PHOTOVOLTAIC GEOGRAPHICAL INFORMATION SYSTEM where we have daily irradiance of 672 W/m2 somewhere in Poland at 11:00 o'clock.
Okay, so we got UV part equal 0.05 * 672 = 33.6 W/m2
Now let's consider human body open parts as 20% of all body surface area which is approx. 1.90 m2 according to Mosteller RD. Simplified calculation of body-surface area. N Engl J Med 1987;317:1098 and divide it by two because we have sun lighting from one direction, not everywhere.
So we got 0.2 * 1.9 * 0.5 = 0.19 m2.
So power of UV-radiation exposure is 33.6 * 0.19 = 6.4 W.
BUT take a look at datasheet of typical UV LED https://www.mouser.fr/datasheet/2/50/UV3TZ-XXX-XX-881014.pdf
so here we have 10mW and in general you can find something from 1 mW to 100 mW, but them almost by any resource (including manufacturers) named dangerous (cancer-inducing, wear protection and so on).
Also I have an mercury lamp which is highly dangerous according to its manual, it has 1 W/m2 power.
Energy of Sun MUCH greater and someone is really wrong here, maybe me? Appreciate your answer.
P.S.: I have a clue: maybe it is our eyes are much more susceptible for UV-radiation than skin and all of that based on danger for eye vision, but on the contrary we have a lot of reflecting surfaces on sunny day which may return us to a problem in numbers I have here.
