In brief: Indoor pollution is not a game

Anyone old enough probably remembers Pacman as a not-very-sophisticated eighties arcade game.

NIWA's version might not keep the kids entertained, but it will tell you some very interesting things about the air you're breathing in your home.

The new PACMAN is a Particles, Activity and Context Monitoring Autonomous Node, otherwise known as a small box, filled with air-quality instruments. It measures the amount of small airborne particles that float around every New Zealand house, and helps track where they've come from.

Airborne particulates are tiny solid or liquid particles, suspended in the atmosphere. Hairs and mucus in our nose and throat generally filter out larger particles, but very small ones – of around one hundredth of a millimetre or the width of a human hair – can settle in the bronchi and lungs, where they can cause health problems.

In New Zealand, poor air quality is blamed for more than 1100 premature deaths a year – mainly through cardiovascular and respiratory impacts – and is reckoned to cost more than $4 billion annually. Most research has so far focussed on air outdoors, but NIWA air quality expert, Dr Guy Coulson, says there's good reason to examine the air in our homes.

"Exposure to pollutants can be much higher indoors than outdoors," he says. "We spend about 80 per cent of our time indoors, so we need to know more about indoor air quality." Work so far has shown that ovens and woodburning stoves can emit very high levels of indoor pollutants. Even the innocent act of making toast can be an intense source of airborne particles, along with incense, pesticides, pets and solvents. Pine-scented cleaning products can react with sunlight to produce particles.

"We want to know if exposure to shortlived, high levels of pollution is bad for you. We're focusing on particles that get deep into your lungs. Can one, five-minute, exposure to very high levels of pollution have an impact on health?" The highest measured concentrations have come from the poor use of wood-burning stoves or solid woodburners. We aim to be able to tell whether neighbours' wood-burners are influencing your indoor air quality as well."

PACMAN has been tested in two Auckland homes. University of Canterbury PhD student Woody Pattinson became part of a living, breathing experiment for several months in a 1960s weatherboard house in Waterview, Auckland. A roomful of instruments, including PACMAN, continuously monitored air quality as he went about his everyday chores.

PACMAN's performance was tested against the more expensive specialised instruments, and was found to perform well. NIWA plans to build 15 or 20 more PACMANs, to be placed in volunteers' homes.

Or you can build your own PACMAN: it's been designed with open source hardware and software, and the relevant files are available by clicking on the link below.

PACMAN files 

The research was funded by the Ministry of Business, Innovation and Employment.

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Air Quality Scientist
We can inhale more pollutants inside our homes than outdoors. PACMAN will help us find out just how many. Credit: Getty Images