Transcript Application of an emissions source apportionment method for primary PM components in a regional air quality model M.

Application of an emissions source
apportionment method for primary PM
components in a regional air quality
model
M. Samaali, M. Sassi, V. Bouchet
Environment Canada, Meteorological Service of Canada, Air Quality Modelling Application
Section, 2121 Trans-Canada highway, Dorval, Québec, H9P 1J3.
M. Moran
Air Quality Research Division, Science and Technology Branch, Environment
Canada, 4905 Dufferin Street, Toronto, ON, M3H 5T4, Canada. Environment
6-8th Oct. 2008, Chapel Hill, NC
Contents
- Introduction
- Implementation of a source apportionment (tagged species)
method in AURAMS
- Emissions inventory analysis
- Modeling results (method’s verification and application)
- Conclusion and future work
– Page 2 – November-7-15
Introduction
- How much does a given source contribute to total PM pollution?
- Two main categories of source apportionment methods used in
Eulerian 3D AQ model (Yarwood et al., 2004):
(1) sensitivity analysis methods
(2) tagged species methods.
- American AQ models (e.g. CMAQ, CAMx) use already both techniques.
- Canadian AQ models (e.g. AURAMS, CHRONOS) used only for
scenarios analysis so far.
Objective: implement, verify and apply a tagged species method in
AURAMS to tag and track primary organic (POC) & elemental carbons
(EC) emissions from 4 sources in the North American domain.
– Page 3 – November-7-15
AQ model description (A Unified Regional
Air quality Modeling System: AURAMS)
Characteristic
Description
Meteorological driver
GEM (offline)
Anthropogenic emissions
Processed by SMOKE (spatial and temporal )
PM emissions
2 inputs fields (PMf and PMc) speciated to 8 species and size
disaggregated to 12 bins.
PM size distribution representation
Sectional method (12 bins)
Lateral boundary conditions
no-gradient, time independent/dependent
Aerosol physics
Nucleation, condensation/evaporation, coagulation, aerosol-cloud
interactions, hygroscopic growth, etc.
Dry deposition
Resistance-based method (Zhang et al., 2001, 2002)
Wet deposition
Scavenging and removal of PM and soluble gases.
– Page 4 – November-7-15
Implementation of a tagged species method
in AURAMS
- 4 source types (area and point):
-on-road (vehicles, trucks, motorcycles),
-off-road & others (marine, air, rail, residential, construction, agriculture,
etc.),
-minor points (stack height < 35m)
-major points (stack height >= 35m)
- 2 tracers (i.e. POC and EC) for each source with 12 bins each: species increase
from 108 to 204 PM species.
- Apply the same physical and chemical processes treatment to the tagged
species as the original POC and EC species:
- Transport (3D advection) and vertical diffusion
- Removal processes (dry deposition, wet deposition and rain, fog,
and cloud processing)
- Emissions (chemical speciation)
– Page 5 – November-7-15
Emissions inventory analysis (1): POC and EC
emissions totals (Jun-Jul-Aug 2002)
Monthly total POC (PM2.5 ) emissions by source
type
Monthly total EC (PM2.5 ) emissions by source
type
PM2.5 total monthly EC of AURAMS main sources
PM2.5 total monthly POC of AURAMS main sources
30
Emissions (tons/month)
Emissions (tons/month)
30
25
Jun-02
20
Jul-02
15
Aug-02
10
5
25
Jun-02
20
Jul-02
15
Aug-02
10
5
0
0
On-road
Off-road &
others
Minor Points
Major Points
Off-road & other sources are major emitter
of POC
On-road
Off-road &
others
Minor Points
Major Points
On-road sources are major emitter of
EC
– Page 6 – November-7-15
Emissions inventory analysis (2) : POC from onroad and off-road & other sources (June 2002)
Total POC (PM2.5 ) from on-road
Total POC (PM2.5 ) from off-road & other.
- Most of the emissions are located in the Eastern domain
- Canadian cities are surrounded by high emission levels
– Page 7 – November-7-15
Emissions inventory analysis (3): POC from
minor and major points (June 2002)
Total POC (PM2.5 ) emissions from minor points
Total POC (PM2.5 ) emissions from major points
- Highest spatial density for minor points
- Highest emission levels for major points
– Page 8 – November-7-15
Runs settings and CPU time analysis
Run period (J-J-A 2002) : started in May. 25th 2002, at 6:00
Lateral boundary (LB) & initial conditions: zero initial conditions &
zero-gradient method for LB conditions
Required computational resources on Environment Canada IBM
cluster:
1 day (24 h) 3 months (2208 h)
Default AURAMS
2h40min
254h20min
(~ 10.2 days)
AURAMS with 8 extra PM
tracers (i.e. 96 species)
4h20min
398h40min
(~16.6 days)
Optimization of the code to keep CPU time increase at minimum
– Page 9 – November-7-15
~ 62% CPU
time
increase
Modeling results (tagging method verification) (1)
Overall domain mean daily POC (PM2.5)
concentrations for J-J-A 2002
Overall domain mean daily EC (PM2.5)
concentrations for J-J-A 2002
0.08
0.08
POC2.5 (Onroad)
POC2.5 (Total)
EC2.5 (Total)
EC2.5 (Off-road &
other.)
EC2.5 (Minor)
0.04
EC2.5 (Major)
0.02
0.06
PC2.5 (ug/m3)
0.06
POC2.5 (Offroad & other.)
POC2.5 (Minor)
0.04
POC2.5 (Major)
0.02
EC2.5 (Total-recalc.)
0.00
POC2.5 (Totalrecalc.)
0.00
1-J
un
8-J
u
15 n
-Ju
22 n
-Ju
n
29
-Ju
n
6-J
u
13 l
-Ju
20 l
-Ju
27 l
-Ju
l
3-A
ug
10
-Au
g
17
-Au
g
24
-Au
g
31
-Au
g
1-J
un
8-J
u
15 n
-Ju
22 n
-Ju
29 n
-Ju
n
6-J
ul
13
-Ju
20 l
-Ju
27 l
-Ju
3-A l
ug
10
-Au
g
17
-Au
g
24
-Au
g
31
-Au
g
EC2.5 (ug/m3)
EC2.5 (on-road)
Date
Date
Average difference: 2.4 10-4 ug/m3 (1.48%)
Average difference: 2.2 10-4 ug/m3 (0.37%)
Good agreement between total POC and EC and their respective tracers sums
– Page 10 – November-7-15
Modeling results (tagging method verification) (2)
POC emissions contributions
POC concentrations contributions
Contribution of POC tagged species to total POC
concentration for continental domain
Percent contribution (%)
Relative contributions to daily POC emissions
Percent contribution (%)
120%
100%
80%
Major points
Minor points
60%
40%
Off-road & other.
On-road
20%
120%
100%
80%
Major points
60%
Minor points
Off-road &
other.
On-road
40%
20%
0%
1
0%
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89
J-J-A 2002
2
3
4
5
6
7
Typical week (June 2002)
There is a correspondence between concentration and emission
contributions for each POC tagged species
– Page 11 – November-7-15
Modeling results (tagging method verification) (3)
EC concentrations contributions
EC emissions contributions
Contribution of EC tagged species in total EC
concentration for continental domain
Relative contributions to daily EC emissions
120%
Percent contribution (%)
Percent contribution (%)
120%
100%
80%
60%
Major points
Minor points
40%
Off-road & other.
20%
On-road
100%
Major points
80%
Minor points
60%
Off-road &
other.
On-road
40%
20%
0%
0%
1
5
9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89
1
J-J-A 2002
2
3
4
5
6
7
Typical week (June 2002)
There is a correspondence between concentration and emission
contributions for each EC tagged species
– Page 12 – November-7-15
Modeling results (tagging method application) (4)
Montreal
Toronto
Ottawa Vancouver Calgary
Contributions of on-road sources to POC
concentrations and emissions
100%
80%
On-road
70%
60%
50%
40%
30%
2%
6%
3%
20%
4%
Montreal
Toronto
Ottaw a
Vancouver
Emiss.
Conc.
Emiss.
Conc.
Emiss.
Conc.
Emiss.
0%
Conc.
10%
Emiss.
Percent in total POC (%)
90%
Conc.
Emiss.
Conc.
Emiss.
Conc.
Emiss.
Conc.
Emiss.
Conc.
Off-road &
other.
Emiss.
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
On-road
Contributions of off-road & other sources to
POC concentrations and emissions
3%
5%
6%
Conc.
Percent in total POC (%)
Off-road & other.
Calgary
On-road POC concentration decrease: dispersion by wind & no significant
surrounding emission sources.
Off-road & other. POC concentration increase: balance with on-road & POC
transport from surrounding sources.
– Page 13 – November-7-15
Conclusion and future work
- The tagged species method implemented in AURAMS verifies well the mass
conservation and hypotheses (linearity) of primary chemistry processes.
- The method’s application is promising for:
(1) Detailed analysis of pollution in Canadian cities
(2) Assessment studies of specific sources (e.g. transportation)
- Code optimization is underway for possible future long-term (annual) runs.
– Page 14 – November-7-15