Keeping an eye on the ups and downs of aerosols in the atmosphere

Research Lives: When I came to Ireland from Lithuania I thought it was a really clean place, but these city measurements show that air pollution is quite high

You study tiny particles in the atmosphere called aerosols. What are they and why are they important?

Aerosols are all around us, they are either liquid or solid particles that are suspended in the air. They are so small that we generally can’t see them but they have a big effect on climate, they reflect or absorb heat from the sun. Some aerosols can also have an impact on human health, particularly the really small ones that we breathe in and they can move into our bloodstream.

Where do these aerosols come from?

We can split them into two main types – natural and “man-made”. The natural ones often come from the sea, where salt gets “aerosolised” and moves into the atmosphere. Our research in Galway has shown that these “sea-made” aerosols can make clouds more reflective, which we argue is good for keeping the Earth cool. On the other hand, aerosols can also be produced when we burn material like coal, peat, wood and car fuels. These man-made aerosols, although beneficial for climate, are harmful for our health.


How do you measure these tiny particles in the air?

I work at Mace Head Atmospheric Research Station in Connemara, where we have instruments that sample the air in near real time and measure both the size of the aerosols and what they are made of. More recently, we have also been working with the Environmental Protection Agency to monitor aerosols in a residential area in south Dublin.

What have you found out about the marine aerosols?

We are so lucky to be able to measure the aerosols on the Atlantic coast at Mace Head in Connemara, not many studies have looked at such a pristine environment, and what we saw has changed thinking about marine aerosols. We were able to show that these tiny particles from the sea can play an important role in boosting cloud formation, which in turn can reflect the sun’s heat and could help to keep the planet from warming.

And what about the city aerosols?

We have been finding that the levels of aerosols from burning peat are really high in the monitoring site in south Dublin. They account for around 70 per cent of the aerosols there in winter, even though peat makes up a tiny fraction, about 4 per cent, of the fuel burned there.

Were you surprised by that?

I was quite shocked, because when I came to Ireland from Lithuania I thought it was a really clean place, but these city measurements show that air pollution is quite high. Also, our research indicates that while we often think of cars causing pollution in cities, burning fuels at home can contribute hugely to poorer air quality.

How will you progress the work?

We hope to keep monitoring aerosols at this location in Dublin and also at more places, including areas with high car traffic. It’s important that we identify the specific sources of aerosols for Ireland, so we can identify how to most effectively reduce the ones that could be causing harm.

What do you do to take a break from the research?

I love travelling, and since coming to work in Ireland I have been taking a lot of road trips here and hiking by the ocean, it’s really beautiful. I also like to read. Learning new things makes me happy, which is probably why I have always enjoyed science, and especially physics.

Claire O'Connell

Claire O'Connell

Claire O'Connell is a contributor to The Irish Times who writes about health, science and innovation