Air pollution kills New Zealanders Solution is electrifying homes and transport

16 October 2023 by Jason Quinn

Air pollution is real and has deadly impacts. In New Zealand we’re 10 times more likely to die from the effects of air pollution than from a car accident. Marc Daalder of Newsroom wrote a detailed feature about the extent of the problem here in New Zealand. Despite lingering fond notions about Aotearoa’s clean, green environment, it is sadly the case that air pollution is a problem in this country. I highly recommend reading this feature—although it will be an uncomfortable read if you have a wood-burning fire or are still specifying them in the homes you design.

The Newsroom article goes into detail about the problem but not so much into how to fix it. There are two key actions needed to slash air pollution at the policy level: electrify transport and build all-electric homes. Switch away not just from natural gas (for heating, cooking or water heating), but also from burning wood (or much worse, coal). 

However the relationship between these two goals is complicated. Home heating with electricity drives New Zealand’s winter electric power peak. We need buildings that are much more energy-efficient, so that the people who occupy them can be comfortable, warm and healthy while requiring radically less electricity. That has the potential to smooth out the winter peak. That would lead to a much cleaner grid and make more power available for electrifying transport.

On the level of personal action, you have some options for improving indoor air quality (IAQ) if you live in a Passive House home or similar. Ensure you have F7 filters in your MVHR unit because the base model G4 filters are designed merely to protect the MVHR from damage, not your lungs. F7 filtration should be specified in the plans and contract for a certified Passive House. Clean and replace filters on schedule (see the last section of this article, which includes graphic images illustrating why you need to check filters regularly).

However, nearly a third of the damage caused by car pollution is from NO2, nitrogen dioxide. This is not filtered out by a F7. There are filters that can tackle NO2, but it would require a retrofit of your MVHR to place another filter in front of the existing filter ie on the supply side. See here for details—it’s a new form of molecular filtration that uses activated carbon.

Sadly if you live in a home built only to the Building Code minimum, you’re limited in what you can do to improve IAQ. You can avoid making it worse, by not bringing into your environment things such as fabrics, furnishing and paint that off gas VOCs, minimising use of flued gas appliances and avoiding unflued gas heaters; and by actively ventilating. But for those living on busy roads, keep windows closed during peak traffic hours. And when your intractable neighbour is burning green wood or soft plastics.

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