Evaluation of the effects of PM2.5 due to domestic solid fuel burning on health outcomes in Scotland

8 Summary and Conclusions

The report details an evaluation of the effects of PM_2.5 from domestic solid fuel burning on health outcomes in Scotland. It highlights that PM_2.5 from domestic solid fuel burning is a significant contributor to air pollution in Scotland, with associated health impacts including premature deaths, respiratory and cardiovascular diseases, and other morbidities. A central estimate of the quantitative effects attribute 160 deaths and 1,814 life years lost annually in Scotland to current solid fuel burning activity.

• Most of the health effects are in urban areas: while the number of households using solid fuels tend to be higher in rural areas, the density of urban areas means that more people are exposed to high air pollution per household burning. This also means that the greatest potential health benefits from reducing solid fuel emissions are also in urban areas, where alternative, secure sources of heat are available (both mains gas and electricity).
• The health impacts are not uniformly distributed with 68% of the impacts observed across 9 (out of total 32) Local Authority areas – furthermore, these Local Authorities which are most significantly affected all lie in the corridor between or in close proximity to Glasgow and Edinburgh. 59% of impacts are observed in 6 Local Authorities – City of Edinburgh, Glasgow City, Fife, North Lanarkshire, Falkirk and South Lanarkshire.
• Policy 2 (Burn Better) has the greatest overall modelled benefit. The relatively modest improvement from Policy 3 (stock upgrades) could be related to very uncertain emission factors for both existing and new stock, for different stove and fuel types. It could also be related to the fact that many stoves, especially in urban areas, will have been installed relatively recently, rather than the measure addressing a long tail of older appliances. More work is needed to improve emission factors, by both testing in the UK and reviewing testing done elsewhere, and also on the costs and availability of very low emission appliances (such as those meeting the Blue Angel standard). To drive significant reductions in emissions would require aligning with a much more ambitious emissions standard (compared to current ‘modern’ burners), and/or encouraging switching away from burning altogether (to, for example, electricity-based forms of heating).
• Policy 1 (Burn Less) was modelled as a uniform 1% reduction in emissions across Scotland. However, the impact of an information campaign of this nature is likely to be more nuanced and could potentially be more successful in urban areas, where the health impacts are greatest. A 1% reduction may be conservative and a larger reduction in fuel use might be achievable through more far-reaching action.
• Demographic differences (in terms of effects, people using solid fuel as primary heat source, etc) do not show a clear, strong trend. Initial insights from this analysis suggest the most deprived households may gain slightly more from a reduction in fuel burning, in particular where this is targeted at urban areas (or the six most affected Local Authorities). However, more deprived households are also likely to be those burning more (alongside the very least deprived – decile 10) and hence support may be required to help these households burn better or burn less. Nonetheless the outcomes emphasise the importance of considering spatial and demographic variations when developing policy, as the impact of interventions can potentially differ across Local Authorities, between urban and rural areas and on different demographic groups. Further work is needed in this area in order to identify specific groups which may be inequitably affected by the policy approaches analysed.
• In terms of population weighted mean (PWM), there is a greater benefit from Policy 2 (Burn Better) in 'other urban areas', rather than for 'large urban areas', while the reverse is true for Policy 3 (Burn Less). This underlines the point that the three scenarios are not mutually exclusive and there may be additive benefits from implementing a more comprehensive, mixed approach. Information campaigns, as well as having an effect in and of themselves, can help facilitate more interventionist measures.
• Uncertainties in the modelling, particularly regarding emission factors and overall fuel allocation to Scotland significantly influence the estimated health impacts. These uncertainties need to be transparent, while ensuring clear public messaging on the reason for policy action on solid fuel burning.