The original article was published with some errors in equations 1 and 2.
The correct Eq.1 is:
$$CE = \sum\nolimits_{i = 1}^n {\left( {{{{F_i} + {F_{i + 1}}} \over 2}} \right)} \times \left( {{t_{i + 1}} - {t_i}} \right) \times 24$$
The correct Eq.2 is:
$${\rm{GWP}} = {\rm{cumulative}}\,{\rm{C}}{{\rm{H}}_{\rm{4}}}\,{\rm{emission}} \times {\rm{34}} + {\rm{cumulative}}\,{{\rm{N}}_{\rm{2}}}{\rm{O}}\,{\rm{emission}} \times {\rm{265}}$$
The publishers apologise for this error.