Influence of Meteorology and interrelationship with greenhouse gases
Quantifying the influence of local meteorology on air ...
Transcript of Quantifying the influence of local meteorology on air ...
Quantifying the influence of localmeteorology on air quality in Zagreb
using generalized additive models
Andreina Belusic 1, Ivana Herceg Bulic 1 and RachelLowe 2
1AMGI, Department of Geophysics, Faculty of Science, University of Zagreb, Zagreb,Croatia
2The Catalan Institute of Climate Sciences (IC3), Barcelona, Spain
November 3, 2014
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1. Motivation and introduction
2. Measuring sites
3. Method
4. Results and discussions
5. Summary and conclusions
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Motivation
• Elevated levels of concentration result of suddenemission and meteorological conditions
• A new approach for the urban area of Zagreb
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Introduction
• GAMs well suited for quantifying and visualizing thepollutant- meteorological relationship
• The logarithm of hourly concentration modelled as asum of non-linear functions of meteorological andtime variables
• Partial effects
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Figure 1 : Satellite view of the town Zagreb (source: Google Maps).Red bubbles indicate air pollution measuring sites and blue bubbleindicates meteorological parameters measuring site.
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Dataset
• Pollutants: CO, SO2, NO2 and PM10
• Meteorological data: temperature, pressure, relativehumidity, precipitation last 4 h, precipitation lastweek, surface wind speed and direction
• Temporal variables: hour of day, day of week, daynumber
• Period: 1 Jan 2006 - 31 Dec 2012
• Sampling: Hourly
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GAMs
• Regression models where smoothing splines are usedinstead of linear coefficients for covariates
• The logarithmic transformation
log(yi) = s0 + s(hd , k) + s(dw , k)
+ s(dn, k) + s(temp, k) + s(press, k)
+ s(rel .hum, k) + s(speed , k) + s(dir , k)
+ s(prec .4h, k) + s(prec .week , k) + εi
(1)
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R2
r 2
CO (mg/m3) ZG3 0,60SO2 (µg/m3) ZG3 0,51NO2 (µg/m3) ZG3 0,43PM10 (µg/m3) ZG3 0,41
Table 1 : The explained variation, r 2, for each model on log scale atZagreb-3.
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Comparison
0.0
0.5
1.0
1.5
Modelled and measured values
CO− comparison, Zagreb 3
2012
Conc. (m
g/m
^3)
Measured values
GAM
Figure 2 : The difference between the measured values ofconcentration (black) and modelled values (red) for CO at Zagreb-3,2012.
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Temperature
−10 0 10 20 30 40
10
03
00
50
07
00
Temperature (°C)
Pa
rtia
l e
ffe
ct
(%)
−10 0 10 20 301
00
30
05
00
70
0
Temperature (°C)
Pa
rtia
l e
ffe
ct
(%)
Figure 3 : CO and PM10
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Mean sea level pressure
980 1000 1020 1040
50
10
01
50
20
0
Press. (hPa)
Pa
rtia
l e
ffe
ct
(%)
980 1000 1020 10405
01
00
15
02
00
Press. (hPa)
Pa
rtia
l e
ffe
ct
(%)
Figure 4 : CO and SO2
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Relative humidity
20 40 60 80 100
50
100
150
200
250
Rel. humidity (%)
Part
ial effect (%
)
20 40 60 80 100
50
100
150
200
250
Rel. humidity (%)
Part
ial effect (%
)
20 40 60 80 100
50
10
01
50
20
02
50
Rel. humidity (%)
Pa
rtia
l e
ffe
ct
(%)
Figure 5 : CO, SO2 and NO2
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Wind direction
0 5 10 15 20 25 30
60
80
10
01
20
14
0
Wind direction (°)
Pa
rtia
l e
ffe
ct
(%)
0 5 10 15 20 25 306
08
01
00
12
01
40
Wind direction (°)
Pa
rtia
l e
ffe
ct
(%)
Figure 6 : CO and SO2
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Wind speed
0 2 4 6 8
050
100
150
200
Wind speed (m/s)
Part
ial effect (%
)
a)
0 2 4 6 8
050
100
150
200
Wind speed (m/s)
Part
ial effect (%
)
b)
0 2 4 6 8
050
100
150
200
Wind speed (m/s)
Part
ial effect (%
)
c)
Figure 7 : CO, SO2 and NO2
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Precipitation last 4 h
0 1 2 3 4 5
50
10
01
50
20
02
50
30
0
Precip. 4h (mm/h)
Pa
rtia
l e
ffe
ct
(%)
0 1 2 3 4 55
01
00
15
02
00
25
03
00
Precip. 4h (mm/h)
Pa
rtia
l e
ffe
ct
(%)
Figure 8 : CO and SO2
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Hour of day
5 10 15 20
60
80
10
01
40
18
0
Hour of day
Pa
rtia
l e
ffe
ct
(%)
Figure 9 : CO
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Day number
0 500 1000 1500 2000 2500
05
01
00
15
0
Day number
Pa
rtia
l e
ffe
ct
(%)
Figure 10 : CO
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Day of week
1 2 3 4 5 6 7
80
85
90
95
10
01
10
Day of week
Pa
rtia
l e
fefc
t (%
)
Figure 11 : CO
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Summary and conclusions
• Emissions have the largest and clear impact on airquality
• Stable atmospheric conditions increase theconcentration and have the negative impact onhuman health
• Changes in concentration quite well estimated
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Improvements
• Traffic density data
• Vertical cross section
• Interactions
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Dataset
• Precipitation last 4 h:
1
10(4Pt + 3Pt−1 + 2Pt−2 + Pt−3) (2)
• Precipitation last week:
1168∑j=1
wj
168∑j=1
wjPt−3−j (3)
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log(yi) = s0 + s(hd , k = 12) + s(dw , k = 7)
+ s(dn, k = 28) + s(temp, k = 9) + s(press, k = 9)
+ s(rel .hum, k = 9) + s(speed , k = 9) + s(dir , k = 9)
+ s(prec .4h, k = 5) + s(prec .week , k = 5) + εi(4)
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Relative importance
• The proportion (in %) of the variation explained bythe j-th predictor variable in the model:
100σ−j
2 − σ2
p∑i=1
σ−j2 − pσ2
(5)
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010
20
30
40
50
Relative importance, CO
Rel. im
port
ance (
%)
Tem
p.
Rel.
hum
.P
ress.
Dir.
Speed
HD
DN
Pre
c.
4h
Pre
c.
week.
DW
Zagreb 1
Zagreb 2
Zagreb 3
020
40
60
80
Relative importance, SO2
Rel. im
port
ance (
%)
Tem
p.
Rel.
hum
.P
ress.
Dir.
Speed
HD
DN
Pre
c.
4h
Pre
c.
week
DW
Zagreb 1
Zagreb 2
Zagreb 3
010
20
30
40
50
Relative importance, NO2
Rel. im
port
ance (
%)
Tem
p.
Rel.
hum
.P
ress.
Dir.
Speed
HD
DN
Pre
c.
4h
Pre
c.
week.
DW
Zagreb 1
Zagreb 2
Zagreb 3
010
20
30
40
50
Relative importance, PM10
Rel. im
port
ance (
%)
Tem
p.
Rel
hum
.P
ress.
Dir.
Speed
HD
DN
Pre
c.
4h
Pre
c.
week.
DW
Zagreb 1
Zagreb 2
Zagreb 3
Figure 12 : FIGURE 2A.Belusic (AMGI) November 3, 2014 25 / 27
Partial effects
• The actual estimated non-linear smooth curves
100Sj(xj)
Sj(xj ,ref )(6)
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Model evaluation
i.e. CO:
• Measurement standard deviation: 0,30 mg/m3
• Model standard deviation: 0,23 mg/m3
• Measurement mean: 0,47 mg/m3
• Model mean: 0,47 mg/m3
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