The open window

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    It’s a windy day on Waiheke, and a gusty northeasterly is washing the trees in my backyard with rain. There’s a southeasterly predicted, strong enough to rattle the latch on the door and slide icy fingers underneath it.

    My WWII-era bach is a leaky old bucket, but I’m fond of her. A real estate ad would call her ‘airy’ with ‘indoor outdoor flow’ – and maybe all the fresh air isn’t so bad.

    On 8 November the world forgot to celebrate World Ventil8 Day, designed to raise awareness of the importance of ventilation, “a crucial part of enabling health and wellbeing.”

    As global and local events dominated the news, 8 November came and went without mass contemplation of the ways better indoor air quality “reduces our exposure to air pollutants and infectious diseases, [enabling] us to think more clearly, sleep better and be more productive.” 

    The special day did produce a newsletter in my email in-tray from the ever-vigilant Public Health Communication Centre (PHCC), an independent organisation hosted by the Department of Public Health at the University of Otago; Professor Michael Baker is a director. 

    His group’s emailed missive was titled World Ventil8 Day – How do our buildings measure up? 

    Although I didn’t actually read it on World Ventil8 Day (my bad) it did make for alarming reading when I finally got around to it on Carbonated Beverage with Caffeine Day (I’m not making that up), eleven days later. 

    So what made me splutter on my uncarbonated caffeinated beverage?

    Ventilation in a building, as we all know, is the introduction of fresh air into a space while removing stale air. What is surprising is how damaging stale air can be. Fresh air helps prevent the spread of respiratory infections – and also reduces cancers, heart attacks, and asthma, as medical researchers Julie Bennett, Kate Macnab and Caroline Halley explain. High levels of moisture in air also cause mould and mildew in buildings, which make conditions like asthma worse. In Aotearoa New Zealand, they say, air pollution is responsible for an estimated 3,317 premature deaths each year, and some 13,155 hospitalisations.

    And newer, more airtight homes can be among the worst offenders. 

    A good way to measure a dangerous lack of ventilation is through the use of a carbon dioxide (CO2) monitor. We exhale CO2, so levels rise as we breathe indoors unless there is effective ventilation – an open window, for example.

    If you are feeling woozy and unable to concentrate, have a headache, a sick feeling or feel sleepy, you may be in a room with too much CO2. If someone in your office or household has a respiratory infection, high CO2 levels would suggest you are inhaling air from their infected lungs. Viruses hang around in stale air for a surprisingly long time.     

    The New Zealand Building Code, say the boffins, lags behind other comparable countries. New Zealand standards recommend ventilation be enough to keep CO2 levels under 1,000 parts per million (ppm). The US Centres for Disease Control recommends a lower threshold of 800 ppm. In Belgium, legislation requires CO2 levels to be displayed on monitors in public spaces; a clever initiative which promotes wider understanding along with clean air.

    There is woefully little monitoring done in New Zealand buildings, say Bennett, Macnab and Halley. “However, data our group has recently collected indicates that New Zealand homes may be reaching well beyond the CDC-recommended maximum level of CO2, particularly overnight in bedrooms. Newer homes may be even more at risk, as homes are becoming increasingly airtight. Other buildings are also reaching well beyond recommended levels. Our recent CO2 monitoring in shared spaces like medical centre waiting rooms and hospitality venues such as pubs and restaurants also indicate levels well above 800 ppm.”   

    Ten years ago, an Auckland based study reported three out of six classrooms had “very poor” ventilation, with carbon dioxide (CO2) levels above 1000 parts per million for 50 percent of the school day.

    Today, the available data shows a wide variety of buildings (like medical centres, homes, bars, restaurants) in New Zealand still do not meet even New Zealand’s comparatively low standards.

    How many of us have caught a cold, the flu or Covid-19 after visiting a medical centre? A few months ago I came down with a miserable week-long flu two days after visiting a stuffy medical clinic. 

    Buildings are not the only issue.

    “I got my teen to take a CO2 monitor to school for a few days,” tweeted Dr Siouxsie Wiles in May this year, “so I could see what the ventilation was like. She’s mostly in a modern open plan building with great ventilation. What the monitor very clearly showed is that the big risk for her is the twice daily school bus.”

    Unlike once-a-year festivals like Lemon Cream Pie Day (Nov 29), Chocolates Day (Nov 29) and Mousse Day (Nov 30), followed by the well-timed Bicarbonate of Soda Day (December 30), why not celebrate Ventil8 Day all year? Jenny

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