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Changes over time

This section presents the changes in the health impacts of human-made air pollution in New Zealand from 2006 to 2016. Results are presented for human-made air pollution (PM_2.5 and NO₂), but are not available by source.

These results come from the HAPINZ 3.0 study, published in July 2022.

Health impacts from overall air pollution have increased since 2006

From 2006 to 2016, there was an increase in deaths, hospitalisations and social costs from human-made air pollution in New Zealand (Table 1). In particular, the number of deaths from human-made air pollution increased from 3,005 to 3,317.

However, accounting for population size, the rate of deaths (per 100,000 people aged 30+ years) and social costs per capita due to air pollution both decreased since 2006. In contrast, the rate of hospitalisations due to air pollution increased.

The increase in health impacts was driven by nitrogen dioxide (NO₂).

Table 1: Changes in health impacts from human-made air pollution (NO₂ and PM_2.5) in New Zealand, 2006 to 2016 (numbers and rates)

Health impacts from NO₂ increased from 2006 to 2016

The health impacts from nitrogen dioxide (NO₂) increased from 2006 to 2016, including premature deaths, hospitalisations and social costs (Table 2). In particular, the number of deaths due to NO₂ increased from 1,580 in 2006 to 2,205 in 2016. The increases in these health impacts all remained even after accounting for population size.

These increases are consistent with the increase in the number of diesel vehicles over this time.

Table 2: Changes in health impacts from human-made NO₂ air pollution in New Zealand, 2006 to 2016 (numbers and rates)

Health impacts from PM₂.₅ have dropped since 2006

From 2006 to 2016, the health impacts of PM_2.5 air pollution decreased in New Zealand (Table 3). This included a decrease in the number of deaths, hospitalisations and social costs due to PM_2.5. These decreases remained even after accounting for changes in population size.

These drops reflect the considerable improvements in domestic fire emissions that have occurred since 2006.

Table 3: Changes in health impacts from human-made PM_2.5 air pollution in New Zealand, 2006 to 2016 (numbers and rates)

Most New Zealanders continue to be exposed to PM₂.₅ at greater than recommended levels

Higher levels of annual average PM_2.5 concentrations can impact on people’s health. The World Health Organization (WHO) recommends that annual average PM_2.5 levels do not exceed 5µg/m³, in their 2021 air quality guidelines.

The percentage of the population living in areas with high PM_2.5 (ie exceeding the WHO 2021 guideline of 5µg/m³) decreased from 2006 (85.1%) to 2016 (81.0%) (Figure 1). However, this still meant that four in five people were exposed to high PM_2.5 in 2016.

A decrease in exposure to high PM_2.5 was also seen for Māori, with the percentage of the Māori population exposed to high PM_2.5 decreasing from 83.6% (2006) to 77.6% (2016).

However, almost all Pacific peoples (94.4%) were exposed to high PM_2.5 in 2016, reflecting differences in where they live.

Figure 1: Percentage of population living in areas with PM_2.5 higher than the WHO 2021 guideline (5µg/m³), total population and by ethnic group, 2006 and 2016

Increase in population exposed to high NO₂, with persisting inequities for Pacific peoples

The percentage of the population living in areas with high NO₂ (ie NO₂ above the 2021 WHO guideline of 10µg/m³) increased substantially from 2006 (23.5%) to 2016 (31.4%) (Figure 2).

The rates were much higher for Pacific peoples, with over half (54.5%) exposed to high NO₂ in 2016.