Auxiliary material for
Indoor and outdoor atmospheric ion mobility spectra, diurnal variation and relationship with
meteorological parameters
Matthew D. Wright, Nicola K. Holden, Dudley E. Shallcross and Denis L. Henshaw
Journal of Geophysical Research (Atmospheres)
Introduction
This auxiliary material includes one table and five figures.
Table A1 (ts01.docx) provides summary statistics (mean, standard deviation, minimum,
maximum, median and 5th and 95th percentiles) for the meteorological parameters (temperature,
pressure, relative humidity, water vapour pressure and wind speed) observed throughout the
measurement periods at each of the three sites. As described in section 2.2 of the main text, these
data were obtained using a Davis Instruments weather station, except wind speed which was
obtained via the UK Met. Office MIDAS Land Surface Station Data database on the British
Atmospheric Data Centre (http://badc.nerc.ac.uk/home/).
Figure A1-A3 (fs01.eps, fs02.eps and fs03.eps respectively) show the time series of recorded data
for each site (after application of quality control criteria, see section 2.2 of the main text) on ion
concentration and mobility, overall conductivity and aerosol contribution to conductivity and
periods from which example spectra (Figures 1 and 2 in the main text, and Figures A4 and A5 in
the Auxiliary Material) are obtained. Figure A1 (fs01.eps) shows data from LI, Figure A2
(fs02.eps) shows data from HI and Figure A3 (fs03.eps) shows data fromHO.
Figure A4 (fs04.eps) shows the daily-averaged ion mobility spectra from site ii) for a 4-day
period (04/11/2002 to 07/11/2002 inclusive) showing a gradual decrease in negative ion mobility
due to changes in the relative importance of the two main peaks at 1.3−1.5 and 2.0−2.2
cm−2 V−1 s−1 respectively.
Figure A5 (fs05.eps) shows ion mobility spectra from ‘composite’ current-voltage curve
comprised of a) the upper 10th percentile and b) the lower 10th percentile of ion concentration
data from the 4-day period from 31/10/2002 to 03/11/2002 inclusive at site ii), highlighting
differences in spectral features at high and low ion concentration respectively, in particular the
lack of the highest mobility positive and negative peaks at low ion concentration (~ 1.7 and 2.2
cm−2 V−1 s−1 respectively). After initially inverting the data, those spectra with the highest (or
lowest) 10% of values by ion concentration were identified. The corresponding unsolved currentvoltage data were then pooled, before inverting again to obtain the ‘composite’ mobility spectrum
for ‘high’ and ‘low’ concentration respectively.
Summary statistics (date/time of measurement, ion concentration and mobility, ratio of polar
conducvitity and charged particle concentration) for each of the spectra presented in Figures A4
(fs04.eps) and A5 (fs05.eps) are given in the main text, Table 2.
Table A1. Summary statistics for meteorological parameters during measurements at each site.
Site
LI
HI
HO
Temperature
Pressure
Relative
humidity
Water vapour
pressure
Wind
speed
°C
hPa
%
hPa
kt
Maximum
28.7
1013
52.9
18.8
−
95th percentile
27.7
1012
50.2
17.7
−
Median
25.5
1008
46.5
14.8
−
5th percentile
23.6
996
36.8
11.6
−
Minimum
22.0
992
32.0
10.7
−
MEAN
25.5
1006
45.2
14.7
−
St. Dev.
1.3
5
4.4
1.7
−
Maximum
27.8
1031
59.9
17.9
−
95th percentile
26.3
1028
56.5
16.2
−
Median
19.1
1016
53.0
11.1
−
5th percentile
15.5
1001
35.0
9.4
−
Minimum
14.1
988
32.0
8.3
−
MEAN
19.6
1016
50.8
11.6
−
St. Dev.
3.3
9
5.8
1.9
−
Maximum
22.0
1029
100.0
16.9
17
95th percentile
19.0
1027
100.0
15.9
13
Median
14.0
1017
82.1
13.0
7
5th percentile
10.0
1006
60.2
10.6
3
9.0
1005
52.6
10.0
0
MEAN
14.3
1017
80.8
13.1
7.4
St. Dev.
3.0
7
12.2
1.8
3.3
Minimum
Figure A1. Time series of recorded data from LI (after application of quality control criteria) on ion concentration and mobility,
overall conductivity and aerosol contribution to conductivity and periods from which example spectra shown are obtained. Also shown
(shaded areas) are periods of interest corresponding to spectra shown in the main text or Auxiliary Material (Figure numbers labeled).
Figure A2. Time series of recorded data from HI (after application of quality control criteria) on ion concentration and mobility,
overall conductivity and aerosol contribution to conductivity and periods from which example spectra shown are obtained. Also shown
(shaded areas) are periods of interest corresponding to spectra shown in the main text or Auxiliary Material (Figure numbers labeled).
Figure A3. Time series of recorded data from HO (after application of quality control criteria) on ion concentration and mobility,
overall conductivity and aerosol contribution to conductivity and periods from which example spectra shown are obtained.
Figure A4. Daily-averaged ion mobility spectra from HI for a 4-day period (04/11/2002 to
07/11/2002 inclusive) showing a gradual decrease in negative ion mobility due to changes in
the relative importance of the two main peaks at 1.3−1.5 and 2.0−2.2 cm−2 V−1 s−1
respectively.
7
Figure A5. Ion mobility spectra from ‘composite’ current-voltage curve comprised of a) the
upper 10th percentile and b) the lower 10th percentile of ion concentration data from the 4-day
period from 31/10/2002 to 03/11/2002 inclusive at HI, highlighting differences in spectral
features at high and low ion concentration respectively, in particular the lack of the highest
mobility positive and negative peaks at low ion concentration (~ 1.7 and 2.2 cm −2 V−1 s−1
respectively).
8