Oral Presentation The Institute of Australian Geographers Conference 2023

Ambient nitrogen dioxide (NO₂) is primarily produced by fossil fuel combustion and has been associated with loss of life expectancy. In 2005 and 2013, Australia adopted Euro4 and Euro5 emissions standards, respectively, for all new vehicles, contributing gradual decreases in NO₂ concentrations, thereafter.

We performed health burden and impact analyses of NO₂ in the Melbourne metro region using established life table methods. Population data in 5-year age groups were retrieved from the Australian Bureau of Statistics (ABS) 2016 census at the statistical area 2 (SA2) level. Mortality rates were calculated from statewide deaths data in 5-year age groups and were applied to SA2 populations. Population weighted annual average exposures were determined using gridded annual NO₂ concentrations from a satellite and land use regression (LUR) model covering the years 2005-2022. We used the WHO guideline concentration-response coefficient for NO₂-attributable mortality (1.023, 95% CI: 1.008–1.037, per 10 μg/m³ annual average) to compare annual years of life lost (YLL) under the scenarios of 2005 and 2022. Finally, we calculated health impacts as incremental gains in life years during the study period based on annual changes in NO₂ exposures and USEPA’s ‘cessation lag’ structure.

In SA2’s across Metropolitan Melbourne, annual average NO₂ exposures were 2.0-21.3 μg/m³ in 2005 and were 2.2 μg/m³ lower on average in 2022. Under sustained NO₂ exposures at 2005 and 2022 levels, we attribute 4495 and 2733 YLL annually, respectively. Linear regression analysis of NO₂ over the study years revealed a negative correlation (p < 0.0001, r = -0.85) with a cumulative 3.6-μg/m³ decrease. The sum of consequent incremental gains in life years came to 5679 over the 17 study years

These data indicate the mortality benefits of current and future NO₂ emissions reductions, for example with policies that promote electric vehicles and renewable energy.