TOWARDS THE REGULATION OF NON-ROAD DIESEL EMISSIONS IN AUSTRALIA

4.2.1. BAU scenario

NRDEs are a significant national source of emissions in the BAU scenario, especially for NO X In 2018, NRDEs emitted 312 kt of NOX, 13.4 kt of PM10 and 13.0 kt of PM2.5. Depending on how other sources are defined, and what is considered to be anthropogenic, NRDEs are likely to be responsible for around 10-15% of national anthropogenic NO X emissions, up to 5% of PM2.5 emissions, and 1-2% of PM10 emissions.

The aggregated national NOX emission over the full period of the emissions analysis (2018-2043) was 9,758 kt. The equivalent figure for PM2.5 was 281 kt.

The net changes in total NRDE emissions between 2018 and 2043 represented a trade-off between, on the one hand, a general increase in the stock and overall activity (and hence diesel consumption) and, on the other hand, a general reduction in average unit emissions (i.e. g/kWh per engine) resulting from the transition to more recent emission standards (in particular, Tier 4) and technology. For any given pollutant and year, the net effect could be either an increase or a decrease in emissions with time.

However, NOX emissions increased systematically; NOX increased by 14% between 2018 and 2028, and by 45% between 2018 and 2043. These changes were driven by a large projected increase in diesel consumption in the mining sector, and notably for engines >560 kW (there was assumed to be little future uptake of large Tier 4 engines in mining).

Figure 6(a) highlights the substantial contribution of mining to NOX emissions. Mining was responsible for around 71% of NOX in 2018, and 85% in 2043.

Figure 6(b) shows the contribution of engines in each power band. Emissions were dominated by larger engines, with 72% being from engines with a power rating of >560 kW. By 2043, the proportion had increased to 87%. These engines are mainly used in the mining sector.

Although the proportion of Tier 4 engines increased with time, in 2043 85% of NOX emissions were still from Tier 1 and Tier 2 engines.

4.2.2. Effects of management scenarios

To illustrate the changes in specific years, the emission reductions for NO X were:

 MS1: 5% in 2028, and 18% in 2043.

 MS2: 1% in 2028, and 40% in 2043.

 MS3: 13% in 2028, and 44% in 2043

Figure 7(a) shows a breakdown of the NOX reductions by economic sector. For all management scenarios, years and pollutants, the bulk of the reduction in emissions (typically 60-80%) was again in the mining sector. In 2043 the effect of MS3 was to reduce NOX emissions from around 450 kt/year to around 250 kt/year. Of the 200 kt/year reduction, 160 kt/year (80%) was in the mining sector.

The bulk of the reduction in emissions of each pollutant was associated with engines >560 kW (Figure 7 (b)). These engines were responsible for between 44% and 98% of the total emission reduction, depending on the scenario, year and pollutant.

4.3. Concentrations and exposure

Figure 8 presents the modelled total annual average NO2 concentrations in 2018. These include all modelled anthropogenic and natural sources plus NRDE emissions. The total (all source) annual mean concentration at the SA2 level was less than 5 µg/m3 across much of Australia, and the highest concentrations – up to maximum of around 38 µg/m3 – were only found in major urban areas.

Figure 9 shows the NRDE contribution to NO 2 concentrations, population weighted by SA2 in 2018. The NO2 contribution by SA2 ranged from almost zero to 6 µg/m3, with some the largest contributions occurring in the mining areas of NSW, Queensland and Western Australia, as well as some remote areas. The NRDE contributions to PM2.5 concentrations by SA2 were smaller, ranging from zero to 1 µg/m3

4.4. Health outcomes

4.4.1. Health burden of NRDEs in 2018 base year

Nationally, 5,387 YLL in 2018 were attributed to NRDE concentrations of NO2 and PM2.5, with NO2 (adjusted, as noted earlier) being responsible for 64% of the total. This YLL represented about 9% of the total mortality burden (61,424 YLL) of PM 2.5 and NO2 from all anthropogenic sources. The large NO2 contribution reflected the relatively high NO X emission rates of NRDEs. For example, the fleetweighted NOX:PM2.5 emission ratio in 2018 was between 13 and 30, depending on the economic sector.

In 2018, the bulk of the total NRDE-attributable YLL occurred in NSW (around 30%) and Queensland (around 28%), with a further 19% in WA and 15% in Victoria. These contributions reflected the total populations of the states, as well as the proximity of the populations to NRDE emission sources.