Research
I am a third year graduate studying for a DPhil as part of the
Sub-Department of Atmospheric, Oceanic
and Planetary Physics at the University of
Oxford. I am funded
by NERC - the National Environment
Research Council. I am a member of Merton
College who have helped to partially fund my studies.
Measuring Air Pollution
I am investigating using FTIR (Fourier transform infra-red) spectroscopy to
measure urban air pollution.
Some work on using FTIR spectroscopy to measure air pollution has been
carried out in the United States of America and on the Continent. However,
very little work has been done in the UK.
Air pollution is measured in the UK by
NETCEN on
behalf of the
Department of the Environment,
Transport and the Regions. They use a
variety
of techniques to do so. From
nitrogen
dioxide diffusion tubes to gas chromatography and mass spectroscopy.
All these methods provide point measurements, over a timescale of 1 hour to
1 month, for a selection of pollutants. The advantages of FTIR spectroscopy
is that it can provide measurements of the average pollutant concentration
over an area, which can be more representative than a point measuremnt, over
a timescale of 5 - 10 minutes, and it can measure a wide-range of pollutants
simultaneously.
FTIR Spectroscopy
For a clear explanation of what FTIR Spectroscopy is, you could do worse
than read AeroSurvey's
guide. I use the
spectrometer in open path mode, which just means that I have a
separate souce & I send the beam of infra-red light from it through the
atmosphere itself to the spectrometer.
I use a Perkin Elmer
Spectrum 2000 spectrometer for my work (see
picture). It has a few additions (an external
source and a collimator, plus mirrors to extend the path) to make it suitable
for use in open path mode.
Air Pollution in Oxford
Air pollution is a significant problem in Oxford, to a large extent due to
the amount of traffic entering the city. To try to improve the situation,
and reduce the amount of traffic in the city centre, the
County and
City Councils introduced the
Oxford
Transport Strategy in July 1999. To monitor the effects of this,
especially the environmental benefits, they launched the
EMITS project in
1997. This includes
monitoring the air
quality across Oxford, but most prominently on Cornmarket Street.
Results
I have measured the spectrum of benzene, and that of 1,3-butadiene, in the
regions 600cm-1 to 1800cm-1 and 2600cm-1 to 3300cm-1 at a resolution of
0.03cm-1, or less. This is necessary, so that I can identify and quantify
these 2 gases, both of which are listed in the National Air Quality Strategy
published by the government in 1997, if I detect them.
The table shows examples of low concentrations of pollutants actually detected.
| Gas | Amount (ppmv) | Estimated standard deviation (%) |
| NO2 | 0.06 | 50.3 |
| N2O | 0.34 | 5.6 |
| SO2 | 0.08 | 31.3 |
| CO | 0.86 | 5.6 |
| CH4 | 2.04 | 6.9 |
Publications
I presented a poster at the 2nd Environmental
Technology 'Car Boot
Sale', organised by the Royal Society of Chemistry, at the NEC in June
1998. As such I have
an
entry in their
Environmental
Technology Car Boot Sale Network Directory.
I presented a poster at the 'Urban Air Quality - Measurement, Modelling and
Management', 2nd International Conference, March 1999, Madrid.
I gave a presentation at the "Aspects of Spectroscopy" meeting, organised by
the IOP (Institute of Physics)
Spectroscopy Group in
September 1999.
Future Work
A series of field measurements is planned for the week of Monday 18th October
to Friday 22nd October 1999. These will be carried out at various locations
in Oxford. In conjunction with these measurements an intercomparison study
with a similar system being tested by the
National Physical Laboratory (NPL) will
be carried out.
Useful Links
Some useful links related to my work that
I've collected.
Pauline's Homepage
