Environmental Engineering Reference
In-Depth Information
C-31
C-31
2007
2007
2008
2008
∆
∆
∆ %
∆ %
NO
2
(µg/m
3
)
NO
2
(µg/m
3
)
22.0
22.0
20.9
20.9
-1.2
-1.2
-5.7
-5.7
PM
10
(µg/m
3
)
PM
10
(µg/m
3
)
12.0
12.0
11.7
11.7
-0.3
-0.3
-2.4
-2.4
AP-2
AP-2
2007
2007
2008
2008
∆
∆
∆ %
∆ %
NO
2
(µg/m
3
)
NO
2
(µg/m
3
)
30.4
30.4
28.7
28.7
-1.7
-1.7
-6.1
-6.1
PM
10
(µg/m
3
)
PM
10
(µg/m
3
)
16.2
16.2
15.6
15.6
-0.5
-0.5
-3.2
-3.2
IRR
IRR
2007
2007
2008
2008
∆
∆
∆ %
∆ %
NO
2
(µg/m
3
)
NO
2
(µg/m
3
)
33.0
33.0
32.7
32.7
-0.3
-0.3
-0.9
-0.9
A-2_C-32
A-2_C-32
2007
2007
2008
2008
∆
∆
∆ %
∆ %
PM
10
(µg/m
3
)
PM
10
(µg/m
3
)
15.8
15.8
15.7
15.7
-0.1
-0.1
-0.5
-0.5
NO
2
(µg/m
3
)
NO
2
(µg/m
3
)
36.9
36.9
35.5
35.5
-1.4
-1.4
-4.2
-4.2
PM
10
(µg/m
3
)
PM
10
(µg/m
3
)
17.1
17.1
16.7
16.7
-0.4
-0.4
-2.3
-2.3
DAT road
C-32
C-32
2007
2007
2008
2008
∆
∆
∆ %
∆ %
NO
2
(µg/m
3
)
NO
2
(µg/m
3
)
18.4
18.4
17.4
17.4
-0.9
-0.9
-5.1
-5.1
11.1
11.1
10.9
10.9
-0.2
-0.2
-1.7
-1.7
PM
10
(µg/m
3
)
PM
10
(µg/m
3
)
Roads affected by the measure
Roads not affected
Fig. 2.
Summary of the impacts on air quality (NO
2
and PM10) of the speed limitation measure
for different areas of study within the Barcelona Metropolitan Area (in red, roads affected by the
measure)
4. Conclusions
The WRF-ARW/HERMES/CMAQ modeling system was applied to assess the
effects on air quality of the 80 km h
−1
speed restriction for the Barcelona
Metropolitan area. The analysis of real circulation patterns shows that the changes
in emissions estimates range from 4% to 11% depending on the area studied.
Consequently, the effects on air quality predicted should focus in the Barcelona
area, mainly over the affected roads, where the reductions on primary pollutants
reach up to 5-8% on 24-h average concentration. The NO
x
emissions decrease in a
VOCs limited area, such as Barcelona, produces local increases of O
3
concen-
trations, especially in the urban plume over the roads affected by the speed limit
(lower than 1% in most cases); nevertheless the O
3
concentrations in downwind
areas remain practically constant. The most positive effects of the management
measure is observed for CO, NO
x
and PM2.5, with daily improvements in air
quality reaching 10-15%. This work shows the importance of introducing speed
limit scenarios in urban areas together with the necessity of using hourly traffic
