A similar study on air pollution / GHG reduction co-benefits for Canada has been conducted by the David Suzuki Foundation. The study which examined a number of measures chose the following six for an indepth analysis:
vehicle fuel economy standards
increased public transit
fuel switching in electricity generation
more renewable resources in electricity generation
community building energy efficiency improvement retrofits.
These measures, which assumed a significant degree of uptake, produced a 9% reduction in GHGs, a 9% reduction in SOx, a 7% reduction in NOx, a 1.4% reduction in VOCs, and a 1% reduction in PM by 2010. This is an example of co-benefits, but is not directly transferable to New Zealand. In many northern hemisphere countries (including Canada) there are significant air quality effects due to SOx, NOx and VOC (through secondary effects due to ozone). New Zealand does not have any similar significant effects due to SOx or VOCs. It does have effects due to NOx and PM10, so it is possible that gains of a similar order to the Canadian assessment could be made.
In the United Kingdom the Department for Environment Food and Rural Affairs (Defra) commissioned the Air Quality Expert Review Group (AQEG) to examine the linkages between climate change and air quality pollutants and their potential mitigation policies (AQEG, 2007).1 This data could be considered in further assessing the relationships relevant in New Zealand, taking into account that the key air pollution issues will be different.
In addition, the Royal Society, the United Kingdom’s National Academy of Science, began a major study into the impact of climate change on global air quality in January 2007. The study looks at how ground-level ozone, a major pollutant and greenhouse gas, may interact with the climate system to affect air quality and possibly influence climate change over the next century. It will also consider the impact of ground-level ozone on human health and the environment. Their study was to be made available towards the end of 2007.2
Some published work has an analysis of the potential impacts of increasing global temperatures on people’s behaviours and potential emissions of local air pollutants in New Zealand. Examples are greater use of air conditioning in summer and decreased use of heating in winter, and the potential increase in evaporative emissions from petrol. These secondary effects have not been included here as they would require a substantial degree of analysis; they may also introduce a level of uncertainty into the results that is not warranted, simply because the basic underlying research has not been conducted in New Zealand.
The Campaign for Clean Air in London recently (August 2007) commented:
Air pollution needs to be tackled holistically with sensible judgments being made in the inevitable trade-offs between air quality and climate change. A classic example is the latest Department for Transport ‘Act on CO2’ calculator which is likely to encourage people to choose cars with diesel engines because of their small CO2 (ie, climate change) advantage even though that generates substantially more of the hazardous particulate matter and nitrogen oxides. We should question whether there is still a place for diesel engines in large cities while there is such a serious public health problem. Instead, we recommend a simple approach to these complicated air pollution trade-offs in cities [through] an ‘Air Pollution Trade-off Principle’.
Treating air pollution holistically requires difficult trade-off decisions between air quality and climate change issues. The Campaign for Clean Air in London encourages policy makers to accept a dis-benefit of up to 5% in climate change terms provided there is an associated benefit of over 50% in air quality terms (and vice versa) ie, one to 10. Such an approach to trade-offs should be considered acceptable since large benefits may be hard to find and small dis-benefits can be rectified relatively easily through other policy measures.3
Such a ‘trade-off’ policy could be explored for use in New Zealand, but its implications have not been explored here.
In Europe, on 10 January 2007 the European Commission set out proposals and options for keeping climate change to manageable levels in its Communication Limiting Global Climate Change to 2° Celsius: The way ahead for 2020 and beyond. This document also considers the potential impacts of climate change reduction measures on air pollution. It states:
Action on climate change also reduces air pollution. For example, reducing CO2 emissions in the EU by 10 % by 2020 would generate enormous health benefits (estimated at € 8 to 27 billion). Such policies will therefore make it easier to attain the objectives of the EU’s strategy on air pollution.
The impact assessments4 for this Communication contain some useful information about how these figures were calculated.
In general there is little relevant overseas research and many of the results are not directly applicable to New Zealand. Of what little research is available, one of the features is lack of consistency, and authors make repeated points about the need for further, more detailed research and analysis. For instance, several studies from the USA and Australia (discussed in detail in Appendices B and C) show that the implementation and uptake of biofuels can have variously positive or negative effects on air quality and greenhouse emissions.