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Emission from ships -

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Emission from ships

Ships burn a very dirty fuel, with high sulphur content. When this fuel is burnt, the emissions
contain large amounts of sulphur dioxide, and sulphates in the solid particles. Global sulphur
emissions attributable to ships are close to 10%. Ships are supposed to burn cleaner fuel close to
shore to protect people who live there. Gerardo Dominguez measures emissions from ships and has
found specific isotopic signatures which allows them to be tracked.

Transcript

Robyn Williams: And so as we approach Copenhagen and those decisions about pollution, one source
that's been forgotten by some is ships.

Kimberly Prather: It's an enormous problem actually in that we've been doing measurements in
California for some time and we're starting to see that as the pollution limits...the restrictions
on cars and trucks are dropping, we're starting to see other pollutants that are turning out to be
from ships, and they're overwhelming at times when the transport conditions bring things down from
the port. We actually see really high levels in San Diego. So it's a growing issue, without
question.

Gerardo Dominguez: Actually we are looking across a channel here between the coast here at La Jolla
and an offshore island, San Clemente Island. And in between here and there is one of the major
shipping channels in the world. Ships go up and down this coast on their way to or on their way
from ports of Los Angeles and Long Beach, and because of that we're actually in somewhat of an
ideal location to study the emissions and their effect on air quality.

Robyn Williams: Gerardo Dominguez who is measuring the muck from shipping, and before him Kimberly
Prather who is a professor chemistry at the University of California, San Diego. Many, including
the IPCC, say it's a really big problem. Few are doing the science.

We never think much of the emissions from ships, although I'd imagine they'd be pretty substantial,
and most of the ports in Australia have got vast amounts of shipping going in and out. So what do
they produce?

Gerardo Dominguez: Ships burn a very dirty fuel that's essentially like a bunker oil, and this fuel
has very high concentrations of sulphur, sometimes on the order of 2% to 5% sulphur by mass. So
when these ships burn this fuel they release large amounts of sulphur dioxide and also fully
oxidised sulphate in the particulate matter, the solid smoke particles that come out of ships. In
local and regional areas like here we have found actually that they account for a much higher
fraction than the global average.

Robyn Williams: When they're close to shore aren't they supposed to burn a cleaner fuel?

Gerardo Dominguez: Recently the state of California has mandated that these ships burn a cleaner
fuel when they're within I believe it's 22 miles from the shoreline, the idea being that it's
supposed to help with their impact on air quality.

Robyn Williams: What do you think of that?

Gerardo Dominguez: I think in general it's a good idea. If you look at the emissions inventories of
what you would expect them to put out and then you put those emissions through models that track
what happens to that sulphur dioxide, you expect them to have a large impact on the air quality in
regions like this. Our research aims at understanding and directly measuring what that impact is.

Robyn Williams: How do you measure the particulates from smokestacks of ships?

Gerardo Dominguez: Not only can we measure how much sulphate there is per cubic metre in the air
but we can actually also measure the relative abundance of isotopes of oxygen in that sulphate. So
oxygen has three stable isotopes; oxygen-16 (which is by far the most abundant), 17, and oxygen-18.
Chemically they are supposed to behave very, very similarly but actually there are small
differences in the abundance of these isotopes in different samples.

So people from the California Air Resources Board took a sampler and directly sampled the emissions
from a ship, and we found that primary sulphate from a ship has a very specific isotopic signature,
like a fingerprint. So that, together with samples that we collected at the Scripps Pier just off
the coast here, by comparing those two samples and their isotopic composition we were able to tease
out the percentage of primary sulphate from ships that is found here in the air.

Robyn Williams: San Diego might be exposed quite substantially, but which are some of the worst
ports in the world, do you know, that are exposed in this way?

Gerardo Dominguez: If you combine the ports of Los Angeles and Long Beach, call them one, I believe
it's about the third largest port. Hong Kong is another major port, Seattle has a major port as
well. And so all of these sites, if we were to apply the methods that we've developed here, we
would expect to see similar signatures.

Robyn Williams: And if the pollution of sulphate is bad, what are the health effects, the suffering
that can be caused as a result?

Gerardo Dominguez: Yes, particulate matter in general, the smog that you breathe in, has been tied
to increased cardiovascular disease, asthma, and an increase in emergency room visits. So during
days when there is bad air quality in urban regions you see an increase in the number of people
complaining from asthma and visits to the emergency room. It seems to stress the immune system once
it gets into your lungs, and because the particulates that are hardest to get out of your lungs are
the ones that stay in your lungs tend to be the smallest ones, those particulates are the ones that
worry public health officials the most.

Robyn Williams: You mentioned before that ships tend to burn a cleaner fuel when they're near the
coast, but what about when they're out to sea burning the nasty stuff? Surely that material travels
quite a bit?

Gerardo Dominguez: That material can travel quite a bit. How far it travels will depend on whether
the sulphur ends up on very small particulate matter, on aerosols that are small, those tend to
stay up in the air the longest, or whether that sulphur gets taken up by sea salt particles. That's
actually one additional aspect of our isotopic approach, it actually allows us to see sulphate
that's made by dissolution or sulphur dioxide being taken up by sea salt particles and then being
oxidised by ozone. So those details I think are still in general poorly understood.

Robyn Williams: What can the ships do actually to clean their act up; using a different sort of
fuel, different sort of engines, or what?

Gerardo Dominguez: Maritime vessels, cargo vessels, cruise ships are run on diesel engines, and to
a large degree the amount of pollution they put up is basically a function of how much fuel they
use. So if you require them to use fuel that does not have as much sulphur then they're not going
to put up as much sulphur dioxide into the atmosphere.

So the reason why they don't, as of now, burn the cleaner fuel is that it's more expensive. It has
to be refined to separate the sulphur out from the active ingredients basically that give it the
propulsion. So these fuels are taken from geologic deposits, and if you want to think of it as the
remains of dinosaurs and vegetation, it's going to be there. The question is the more processing
you do to it to make it cleaner-burning, the more expensive it's going to be.

Robyn Williams: Dr Gerardo Dominguez at the chemistry department at the University of California
San Diego, developing a way to identify which ship is responsible for what kind of filthy
discharge. And here in Australia both the port of Brisbane and Fremantle in the west are doing
studies to find out emission loads from shipping. Results are expected at the end of the year. And,
as Kimberly Prather just said, it's a big problem.