Global Guidance On LCIA Indicators: Impacts Of Particulate Matter And Of Land Use

Improving life cycle impact assessment models is crucial. The flagship project of the UNEP-SETAC Life Cycle Initiative provides global guidance and consensus on environmental LCIA indicators for climate change, particulate matter impacts, land use impact on biodiversity, water scarcity and water use impacts on human health. We present the recommendations and latest developments in two impact categories, particulate matter and land use.

We present a framework for calculating characterization factors for indoor and outdoor emissions of primary PM2.5 and secondary PM2.5 precursors, enabling to account for the exposure to fine particulate matter (PM2.5) pollution in LCA, a major contributor to human disease burden. The model first provides default aggregated exposure factors for archetypal indoor and outdoor, urban and rural sources. It then customizes these archetypes for 3646 real-world urban areas in 16 sub-continental regions. Population intake fractions (iF) are highest in Southeast Asia, with 95% of the iF ranging from 4.3 to 160 ppm across 3646 cities (population-weighted mean of 39 ppm) and from 0.2 to 6.3 ppm (mean 2 ppm) across the 16 sub-continental rural regions. Intake fractions in residential and occupational indoor source environments range from 470 ppm to 62000 ppm, as function of air exchange rate and occupancy. Indoor exposure typically contributes 80–90% to overall exposure from outdoor sources. These intake fractions are then combined with average and marginal non-linear dose-response slope and severity factors to yield characterization factors expressed in DALY/kg precursor emitted.

For land use, the selected model and indicator builds on species richness, incorporates the local effect of different land uses on biodiversity, links land use to species loss, includes the relative scarcity of affected ecosystems, and includes the threat level of species. Global average characterization factors (CFs) are interim recommended to quantify potential species loss (PSL) from land use and land use change, suitable for hotspot analysis in LCA. These CFs are not valid for comparative assertions. Developments are required before upgrading this interim recommendation to a full recommendation of CFs, including the refinement of land use classes, the inclusion of additional taxa, and the test of CFs in sufficient case studies.