Aggregating local, regional and global burden of disease impact assessment: detecting potential problem shifting in air quality policy making

Purpose Quantitative risk assessment (QRA) has been applied widely in environmental decision-making. Despite its advantage in taking locally specific details into consideration, problem shifting may occur due to its relatively narrow focus. To achieve a broader perspective, we propose that the combined use of QRA and life cycle assessment (LCA) may be beneficial. The feasibility and effectiveness of a hybrid approach of QRA and LCA were evaluated by considering alternative future air quality scenarios. Methods Future air pollution emission scenarios based on different state-based environmental agency policies in Victoria, Australia, were considered to explore ways to reduce problem shifting. QRA was used to estimate human burden of disease (BoD) for the local population due to particulates and tropospheric ozone under ‘Low Impact’ and ‘Most Likely’ scenarios. To detect potential problem shifting, LCA was performed for other associated impact categories such as climate change potential. Disability-adjusted life years (DALYs) were used as a common metric to facilitate direct comparisons and aggregation between results of QRA and LCA. Results and discussion While the ‘Low Impact’ scenario was developed to project a scenario with reduced human health impacts (among other environmental impacts), the overall assessment revealed that BoD impacts may suffer a net increase under this scenario. The QRA suggested about 0.74 kilo DALYs (kDALYs) were saved annually; however, the LCA indicated that more impacts were expected, over 8 kDALYs per year. Hence, it was projected that reducing local impact by improving local air quality would shift more problems elsewhere. Therefore, using QRA alone that focuses on local impacts could result in an inappropriate scenario being preferred and improper policies being set. Conclusions The outcomes of this study revealed the importance of applying a broad perspective in environmental decision-making. QRA appeared to be a suitable tool to assess local BoD impacts caused by ambient air pollutants. However, by also including LCA, impacts could be more comprehensively assessed. Combined use of QRA and LCA enables the analyst to account for locally specific considerations while reducing potential problem shifting to more distant receptors.