. 2022 Dec 16;28(1):69–103. doi: 10.1007/s10666-022-09863-0

Table 5.

Environmental parameters

$e_{s}$	The rate of CO₂ released to extract a unit of raw material in supplier s during the COVID-19 pandemic and lockdown days,
$e_{f}$	The rate of released CO₂ to produce a unit of product in factory f during the COVID-19 pandemic and lockdown days,
$e_{i}$	The rate of CO₂ released to handle and distribute 1 unit of product in the CDC i during the COVID-19 pandemic and lockdown days,
$e r_{i}$	The rate of CO₂ released to collect, inspect, consolidate, and sort 1 unit of the returned product in the CDC i during the COVID-19 pandemic and lockdown days,
$e r_{f}$	The rate of CO₂ released to remanufacture 1 unit of the returned product in the factory f during the COVID-19 pandemic and lockdown days,
$e r_{b}$	The rate of CO₂ released to recycle and landfill 1 unit of the returned product in RLC b during the COVID-19 pandemic and lockdown days,
$E T C_{sf}^{ts}$	CO₂ released by shipping alternative ts to send a unit of raw material from supplier s to factory f for a unit distance during the COVID-19 pandemic and lockdown days,
$E T C_{fi}^{tf}$	CO₂ released by shipping alternative tf to send a unit of product from factory f to CDC i for a unit distance during the COVID-19 pandemic and lockdown days,
$E T C_{ic}^{ti}$	CO₂ released by shipping alternative ti to send a unit of product from CDC i to customer c for a unit distance during the COVID-19 pandemic and lockdown days,
$E T C R_{ci}^{tc}$	CO₂ released by shipping alternative tc to collect a unit of returned production from customer c to CDC i for a unit distance during the COVID-19 pandemic and lockdown days,
$E T C R_{if}^{ti}$	CO₂ released by shipping alternative ti to send a unit of the returned product to be remanufactured from CDC i to factory f for a unit distance during the COVID-19 pandemic and lockdown days,
$E T C R_{ib}^{ti}$	CO₂ released by shipping alternative ti to send a unit of returned production from CDC i to RLC b for a unit distance during the COVID-19 pandemic and lockdown days,
$E T C R_{bs}^{tb}$	CO₂ released by shipping alternative tb to send a unit of returned production from RLC b to supplier s for a unit distance during the COVID-19 pandemic and lockdown days,