Cleaner cars helping cut pollution
Improvements to the motor vehicle fleet are helping to reduce air pollutant emissions in New Zealand, according to a new report from the Ministry for the Environment (MfE) and Stats NZ.
However, the same document also notes the impact of air pollution from vehicles is still associated with a high number of hospitalisations, premature deaths and substantial social costs.
The findings come in the latest three-yearly update about air quality in New Zealand, which brings together recently updated Stats NZ indicator data along with insights from research literature.
The report, titled Our air 2024, shows air pollutant levels have decreased at most monitoring sites over the past eight years.
However, some sites showed worsening air quality, while pollutant levels at sites where air quality improved were sometimes still above levels in World Health Organisation (Who) guidelines.
Natasha Lewis, MfE’s deputy secretary – strategy, stewardship and performance, says emissions from motor vehicles, aviation, shipping and rail, were lower in 2019 than in 2012 for all monitored pollutants, except sulphur dioxide.
“Air pollutants from motor vehicle exhaust emissions are reducing per kilometre as a result of vehicle emissions standards, lower-emissions vehicles and improvements in engine technology and fuel quality,” she explains.
However, the nation’s vehicle fleet reached its largest size to date in 2022 and annual kilometres travelled by motorists have increased over recent decades.
Lewis, pictured, adds road vehicles contribute significantly to different types of air pollution and were the largest source of nitrogen oxides, at 39 per cent, in 2019.
Another main contributor to air pollution is burning wood for home heating and it continues to be a major source of PM2.5, which is fine, airborne particulate matter that is small enough to be inhaled and can enter the bloodstream.
Looking ahead, the report says it's highly likely air pollutants from vehicle exhaust emissions will reduce, while other non-exhaust air pollutant emissions such as tyre and road wear will continue to increase.
It adds how air pollution from transport will evolve and impact public health is uncertain.
Our air 2024 also notes current air quality monitoring doesn’t provide a complete picture of air quality in Aotearoa.
“Councils generally monitor air pollutants in areas that we know are at risk of poor air quality and where people are exposed,” says Lewis.
Natural pressures on air quality also come in for consideration and the document notes these may alter as our climate changes.
“Areas with drier conditions could experience worsening air quality due to higher fire risks and more windblown dust,” adds Lewis.
Warmer temperatures and higher carbon dioxide concentrations could also increase the suitable growing areas of major pollen-producing species and enable plants to produce more pollen for longer.
