UV dosimetry and measurement

Question 1

How is UV measured? What is typically measured?

Answer 1

• Range of instruments can be used, all of which are wavelength sensitive and have a restricted response range. This means the instrument has to be matched to the anticipated spectral range and level of irradiance. Therefore, for anything unknown or close to a limit, it is better to take a spectrum to provide a better estimate.
• Spectral irradiance (mW/cm) or radiant exposure (J/cm) is typically measured.

Question 2

What effects does UV exposure have on the body? What effects does it have on DNA?

Answer 2

Skin photochemical:
- Vitamin D production.
- Sunburn and erythema.
- Skin cancer and skin ageing.
Eye photochemical:
- Photo-keratitis cataracts.
Eye thermal:
- Welder’s flash.

Can cause damage to DNA with UVB being more damaging than UVA.

Question 3

How are UV hazards measured?

Answer 3

• Weighting curves are available for different photochemical effects which provide the effectiveness vs the UV wavelength. An ICNIRP overall hazard weighting curve is also available.
• All weighting curves have a peak around the UVB range but decrease for the UVA range, although UVA is still hazardous.
• Thermal hazards do not require any weighting.

Question 4

What is the Control of Artificial Optical Radiation at Work Regulations 2010 AOR10 workplace thermal daily limit due to artificial sources of UVA?

Answer 4

Irradiance (not weighted) = 10 000 J/m^2 to eyes over any 8 hour period.

Question 5

What is the Control of Artificial Optical Radiation at Work Regulations 2010 AOR10 workplace photochemical daily limit due to artificial sources of UV?

Answer 5

Effective irradiance (ICNIRP weighted) = 30 J/m^2 to skin and eyes over any 8 hour period.

Question 6

What is the main set of UK regulation covering UV?

Answer 6

The Control of Artificial Optical Radiation at Work Regulations 2010 (AOR10).

Question 7

What is required in areas where there is capacity to exceed an exposure limit?

Answer 7

• Risk assessment.
• Local rules.
• UV RPS.
• Access control.
• PPE.
• Training.
• Audit.

Question 8

What is the difference between irradiance and effective irradiance?

Answer 8

Spectral irradiance is a measurement value. Effective irradiance is weighted to account for the likelihood of an adverse effect.