Heating, vehicles pollution leaders
WELLINGTON: Home heating and vehicle use are the biggest causes of poor air quality in New Zealand, new statistics show.
The Ministry for the Environment and Statistics New Zealand has released its latest report in the environmental reporting series as legally required.
‘‘Our air 2018’’ showed there had been an improvement and levels of some pollutants declining, but there were persistent problems, such as heat sources.
Burning wood or coal to heat a home is the largest single cause of air pollution by humans in New Zealand.
Wood burners heat 33% of North Island homes and 47% of South Island homes, according to the last available data. However, burning wood as a heat source had declined over time.
Coal burning accounts for about 4% of residential emissions, but the report said this could be an underestimate.
Other human factors contributing to air quality include burning wood for construction and manufacturing processes.
Emissions from vehicles are also a major contributor of poorer quality air from exhausts, and also through the wearing and abrasion of pavement, tyres and brake pads.
Shipping was an important source of sulphur dioxide emissions, and the report said the size and number of international cargo ships and cruise ships visiting New Zealand continued to grow.
Recent intensification of agriculture could be causing an increase in ammonia emissions, which could affect ecosystems and biodiversity.
PM10 is particles less than 10 micrometres and PM2.5 is particles less than 2.5 micrometres.
In general, the smaller the particle, the greater the effect on human health, because they penetrate more deeply into the human body.
Modelling suggested that in 2016 the number of premature adult deaths per 100,000 people from exposure to PM10 in New Zealand was 8% lower than in 2006.
But relative improvements in air pollution effects appeared to be largely due to more people living in areas with lower PM10, such as Auckland, rather than an actual reduction in the pollution.