Life-saving sensors

When we think of “air quality”, we imagine polluted air around our workplaces, factories and homes. Air quality can be affected by natural events (volcanoes, bushfires, windstorms and pollen) and by human activities (vehicle exhaust fumes, industrial activities, wood heaters, cement and concrete emissions).

Air pollutants contribute directly to climate change and already lead to millions of premature deaths, extensive crop losses and declines in biodiversity.

But it’s actually the air quality inside our homes and workplaces in Australia that’s a big concern for many of us, because we spend a lot of our time indoors. This is often where we breathe our most polluted air. From gases released by treated furniture, adhesives from carpets, paint fumes, carbon monoxide leaks from indoor heaters, aroma diffusers, mould spores and volatile organic chemicals from cleaning products, we are exposed to many more hazardous gases than we think!

We really need to have knowledge of how good our air quality is to maintain safe and healthy living.

Health impacts of poor indoor air quality include headaches, fatigue and aggravation of conditions such as asthma and allergies. These effects are greater when we are exposed to higher amounts of pollutants and over longer times, so we really need to have knowledge of how good our air quality is to maintain safe and healthy living.

However we look at it, measuring and controlling indoor air quality should be a top priority. This is a main focus of my research: I am using new, low-cost devices to develop better and smarter sensors for detecting hazardous gases and explosives.

The new design I am working on uses miniaturised electrode devices with tiny amounts of a liquid salt called an ionic liquid. The unique ionic liquid properties allow gases to be absorbed and transported to the electrode, where they can be detected using redox reactions. We are essentially “doing chemistry with electricity”!

I have directed much of my research at understanding fundamental gas behaviour in ionic liquids and using this knowledge to develop miniaturised, low-cost sensors for a range of hazardous gases and explosives. I am excited to see my research now being developed into real devices that are being sold commercially and used worldwide.

I am using new, low-cost devices to develop better and smarter sensors for detecting hazardous gases and explosives.

My research doesn’t only have applications for monitoring indoor air quality – it can also be used for safer storage of hydrogen in vehicles and at refuelling stations; detecting oxygen levels in confined spaces; monitoring contamination in ground water; and screening for explosives to prevent terrorist incidents.

So, how did I get into this field? I was the first person in my family to attend university, and I never imagined I would have a successful career as a scientist. As a child, I had a natural talent for maths and science, and I found I really excelled at maths. However, after doing work experience at an accountancy firm at age 17, I realised I didn’t want to sit at a computer and type in numbers all day for the rest of my life.

That’s when my A-level chemistry teacher suggested I should do a chemistry degree, because it’s a perfect combination of doing practical hands-on work while also using my maths skills. And now – something I still find hard to believe – I’m a newly minted Professor of Chemistry.

I was the first person in my family to attend university, and I never imagined I would have a successful career as a scientist.

The real turning point in my early career was when I was found myself left on my own when my postdoc supervisor moved to Europe. I decided that if I wanted to give academia a go, I would need to come up with a research direction in which I could start my independent research. A chance meeting with someone from the ChemCentre (located next to Curtin Chemistry) led me to know that they were having some issues with their gas sensors, and that’s where the idea to investigate gases came about.

The field of gas monitoring is now really taking off, with new ingestible and wearable gas sensors being researched and coming to market over the last few years. Some of this great technology is coming out of excellent research labs in Australia.

In recent times, with COVID at the forefront of everyone’s minds, the focus on measuring air quality as an indirect measure for virus transmission has led many people to buy their own personal CO₂ monitors. These handheld devices give instant read-outs of CO₂ levels, allowing for quick decisions on whether to increase ventilation, or move outside until the dangerous values decrease to more normal levels.

It could be a sensor that we can plug into our mobile phones allowing us to take control over our own air quality.

Together with the internet of things, so-called “smart sensors” could be programmed to turn on ventilation systems in offices when toxic gas levels build up to dangereous levels. Also, with future energy needs shifting towards technologies such as “green hydrogen”, it will be essential to have accurate and widespread sensors to detect leaks of this highly explosive gas.

The next big challenge in the field is to bring the sensor to the everyday person. It could be a sensor that we can plug into our mobile phones, allowing us to take control over our own air quality. Much like the highly successful glucose sensor and the personal pregnancy test that are both available to purchase from pharmacies, a personalised gas monitor could give you important knowledge about your surroundings so that you can make informed decisions about your safety.

Finding the materials and electrodes that are sensitive and selective enough to detect the gases we want to measure is quite complex and challenging – but they also present many opportunities for future scientific discoveries, and keep me passionate about my research on life-saving sensors.

 

As told to Graem Sims for Cosmos Weekly.