2.12 Samples
The results for this section are a sum of the manufacture, supply, storage and end of life impact of samples.
Analysis
Sample analysis:
(Number local samples x % local analysed x analysis emission factor)
+ (number central samples x % central analysed x analysis emission factor)
Example in which 5000 local samples and 5000 central samples are 100% analysed:
(5000 x 100% x 0.0459) + (5000 x 100% x 0.0459) = 459 kg CO2 eq
Note: the user is asked for the split between local/central and ambient/chilled/frozen but that does not matter for the analysis, as the same factor is used in all cases.
Sample shipment (supply)
Local:
No transport impact
Central:
If ‘central’ (for example, sent from the US to the UK):
Ambient:
[(Number central samples x % ambient x sample mass) + (ambient box weight
x ((number central samples x % ambient) / samples per shipment))
x distance air x air freight emission factor]
+ [[(number central samples x % ambient x sample mass) + (ambient box weight
x ((number central samples x % ambient) / samples per shipment)) x distance road
x ambient road freight emission factor] + [(ambient box emission factor
x ((number central samples x % ambient) / samples per shipment))]
Example in which 5000 samples are supplied from US to UK, with 50% ambient and 500 samples per box:
[(5000 x 50% x 0.01) +(0.2 x ((5000 x 50%)/500)) x 6000 x 0.00123] + [(5000 x 50% x 0.01)
+(0.2 x ((5000 x 50%)/500)) x 1000 x 0.00012] + [0.35 x ((5000 x 50%)/500)]
= 197 kg CO2 eq
Frozen:
[(Number central samples x % frozen x sample mass) + ((frozen box weight + dry ice per frozen box weight)
x ((number central samples x % frozen) / samples per shipment)) x distance air x air freight emission factor]
+ [[(number central samples x % frozen x sample mass) + ((frozen box weight + dry ice per frozen box weight)
x ((number central samples x % frozen) / samples per shipment)) x distance road
x chilled road freight emission factor]
+ [(frozen box emission factor + (dry ice amount per box x dry ice emission factor))
x ((number central samples x % frozen) / samples per shipment))]
Example in which 5000 samples are supplied from US to UK, with 50% frozen, 1000 samples per box and 5 kg of dry ice per box:
[(5000 x 50% x 0.01) +((7.2 + 5) x ((5000 x 50%)/1000)) x 6000 x 0.00123]
+ [(5000 x 50% x 0.01) +((7.2 + 5) x ((5000 x 50%)/1000)) x 1000 x 0.00014]
+ [(26.5 + (5 x 4.1)) x ((5000 x 50%)/1000)]
= 535 kg CO2 eq
Chilled:
[(Number central samples x % chilled x sample mass) + ((chilled box weight + dry ice per chilled box weight)
x ((number central samples x % chilled) / samples per shipment)) x distance air x air freight emission factor]
+ [[(number central samples x % chilled x sample mass) + ((chilled box weight
+ dry ice per chilled box weight) x ((number central samples x % chilled)
/ samples per shipment)) x distance road
x chilled road freight emission factor]
+ [(chilled box emission factor + (dry ice amount per box x dry ice emission factor))
x ((number central samples x % chilled) / samples per shipment))]
Example in which 5000 samples are supplied from US to UK, with 50% chilled, 1000 samples per box and 3 kg of dry ice per box:
[(5000 x 50% x 0.01) +((4 + 3) x ((5000 x 50%)/1000)) x 6000 x 0.00123] + [(5000 x 50% x 0.01)
+((4 + 3) x ((5000 x 50%)/1000)) x 1000 x 0.00014] + [(10.8 + (3 x 4.1)) x ((5000 x 50%)/1000)]
= 377 kg CO2 eq
Note: this needs to be calculated for each country to which samples are sent. In this example, it is assumed to be just the UK. If multiple countries are used, then the ratio of patients is used to calculate the number of samples going to central. For example, 100 patients in UK and 200 in Spain would have a ratio of 33.3% samples coming from UK and 66.7% samples from Spain.
Storage
Local:
(Number of local samples x % stored x length of storage (yrs) x 365
x storage electricity consumption at specified temperature x country electricity emission factor)
Example in which 10,000 local samples are taken, with 50% of samples stored for 5 years at -20 degrees in the UK:
(10,000 x 50% x 5 x 365 x 0.000233 x 0.275) = 584.7 kg CO2 eq
Central:
(Number of central samples x length of storage (yrs) x 365
x storage electricity consumption at specified temperature x country electricity emission factor)
Example in which 10,000 central samples are taken, with 50% of samples stored for 5 years (1825 days) at -20 degrees in the US:
(10,000 x 50% x 5 x 365 x 0.000233 x 0.373) = 793 kg CO2 eq
End of Life
Sample:
(Number of local samples x default sample weight x end of life emission factor)
+ (number of central samples x default sample weight x end of life emission factor)
Example in which 5000 local samples and 5000 central samples are disposed:
(5000 x 0.01 x 1.57) + (5000 x 0.01 x 1.57) = 157 kg CO2 eq
Note: the user is asked for the split between local/central and ambient/ chilled/ frozen, but this does not matter for EoL, as it is assumed that the same EoL route and the same emission factor is used in all cases.