NTR: Request for P06 MED/hr

[nvsvocabs]

Required

Term name (PrefLabel)

MED/hr

Definition

MED (minimal erythema dose) of UV radiation per hour

Optional

Sources/references

Solar Ultraviolet Radiation - World Health Organization - https://www.who.int/uv/health/solaruvradfull_180706.pdf

ORCID

https://orcid.org/0000-0001-6840-6785

[gwemon]

@botheredbybees Sorry for the time it took to respond to your request. What are the quantities or parameters associated with this unit of MED per hour? I see that in the document referenced above, it says: "Ambient UVR may be measured in purely physical units or weighted using an erythemal response function to give biologically effective UVR, expressed as joules per square metre (Jm-2), minimal erythemal dose (MED), standard erythemal dose (SED) or the solar UV index.". It also defines MED as "that dose of UVR required to produce a barely perceptible erythema in people with skin type 1 (200 Jm-2 of biologically effective UVR)." So "MED per hour" would be defined as e.g. "Units used to quantify ultra-violet radiations (UVR) received in an elapsed time of one hour (3600 seconds) where the quantity of UVR is expressed as a function of the dose required to produce a barely perceptible erythema in people with skin type 1 (200 Jm-2 of biologically effective UVR) ." Would that be correct?

[botheredbybees]

Thanks Gwen. This looks good to me. That said, MEDs are a pathetic unit of measurement, aren't they?. You totally deserve an award for getting this written up...

[image: GoodJob.jpg]

On Tue, 8 Jun 2021 at 05:40, Gwen Moncoiffé @.***> wrote:

@botheredbybees https://github.com/botheredbybees Sorry for the time it took to respond to your request. What are the quantities or parameters associated with this unit of MED per hour? I see that in the document referenced above, it says: "Ambient UVR may be measured in purely physical units or weighted using an erythemal response function to give biologically effective UVR, expressed as joules per square metre (Jm-2), minimal erythemal dose (MED), standard erythemal dose (SED) or the solar UV index.". It also defines MED as "that dose of UVR required to produce a barely perceptible erythema in people with skin type 1 (200 Jm-2 of biologically effective UVR)." So "MED per hour" would be defined as e.g. "Units used to quantify ultra-violet radiations (UVR) received in an elapsed time of one hour (3600 seconds) where the quantity of UVR is expressed as a function of the dose required to produce a barely perceptible erythema in people with skin type 1 (200 Jm-2 of biologically effective UVR) ." Would that be correct?

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[gwemon]

@roy-lowry @dr-shorthair what are your views on this unit? If I understand correctly 1 "MED" is equivalent to 200 Joule per square metre. J/m2 is the SI unit of radiant exposure or fluence which is defined in Wikipedia as "the radiant energy received by a surface per unit area, or equivalently the irradiance of a surface, integrated over time of irradiation". Here we have MED per hour meaning that the quantity associated with it would be an "exposure rate" so maybe I need to modify slightly my definition to be: "Units used to quantify the exposure to ultra-violet radiations (UVR) in an elapsed time of one hour (3600 seconds) where the quantity of UVR is expressed as a function of the dose required to produce a barely perceptible erythema in people with skin type 1 (200 Jm-2 of biologically effective UVR)."

[dr-shorthair]

I never heard of MED but if it is 200 J/m2 then it is a legitimate uom, and therefore MED/hr is as well, with a conversion factor of 200/3600 to the SI unit of J/m2/s.