Improving odour assessment in LCA - the odour footprint
Journal article, 2014
Purpose Odour is an important aspect of systems for human
and agricultural waste management and many technologies
are developed with the sole purpose of reducing odour.
Compared with greenhouse gas assessment and the assessment
of toxicity, odour assessment has received little attention
in the life cycle assessment (LCA) community. This article
aims to redress this.
Methods Firstly, a framework for the assessment of odour
impacts in LCA was developed considering the classical
LCA framework of emissions, midpoint and endpoint indicators.
This suggested that an odour footprint midpoint indicator
was worth striving for. An approach to calculating an areal
indicator we call “odour footprint”, which considers the odour
detection threshold, the diffusion rate and the kinetics of
degradation of odourants, was implemented in MATLAB.
We demonstrated the use of the characterisation factors we
calculated in a case study based on odour removal technology
applied to a pig barn.
Results and discussion We produced a list of 33 linear characterisation factors based on hydrogen sulphide equivalents, analogous to the linear carbon dioxide equivalency factors in use in carbon footprinting, or the dichlorobenzene equivalency factors developed for assessment of toxic impacts in LCA. Like the latter, this odour footprint method does not take local populations and exposure pathway analysis into account—its intent is not to assess regulatory compliance or detailed design. The case study showed that despite the need for materials and energy, large factor reductions in odour footprint and
eutrophication potential were achieved at the cost of a smaller factor increase in greenhouse emissions.
Conclusions The odour footprint method is proposed as an
improvement on the established midpoint method for odour
assessment in LCA. Unlike it, the method presented here
considers the persistence of odourants. Over time, we hope
to increase the number of characterised odourants, enabling
analysts to perform simple site-generic LCA on systems with