1. Modelling atmospheric transport of Benzo(a)Pyrene with CMAQ
The need for time resolved emissions
V. Matthias, A. Aulinger
GKSS Research Centre, Geesthacht, Germany

2. Research Objectives
Investigation and assessment of air pollution , i.e. persistent organic pollutants (POPs) in Europe
Deposition of POPs into the North and Baltic Sea
Focus on coastal regions
Evaluation of past and forecast of future developments (scenarios) on time scales of decades
Assessment of the impact of regulations

3. CMAQ model domain and nest
54x54 km2 grid
18x18 km2 grid
30 vertical layers

4. BaP
was included as a new substance into CMAQ
is mainly particle bound
we consider 3 particle modes and the gas phase
model results can be compared to (few) measurements

5. Meteorology, initial and boundary conditions
Meteorological fields are calculated with MM5
Boundary Layer: MRF (Hong and Pan, 1996)
Microphysics: Reisner 2, incl. ice, snow and graupel (Reisner et al., 1998).
Cumulus: Kain Fritsch 2, (Kain and Fritsch, 1993)
One year is represented by four months (January, April, July and October), selected years will be calculated (starting with 2001)
Interest in long term runs / use of met. fields from other models (e.g. CLM)
ICs: constant profiles, one day spinoff time for each month
BCs: Either constant profiles or daily means from a global CTM (MOZART)

6. Emissions
Hourly anthropogenic emissions of 2000 for CO, NOx, SO2 , NH3 , NMVOC (in RADM speciation), PM2.5 and PM10 on the 54 km and 18 km CMAQ grid provided by the IER Stuttgart.
Biogenic emissions of terpenes and isoprene from POET database (monthly values for 2000 on 1° x 1°), addition of a diurnal cycle for isoprene, no diurnal cycle for terpenes
Sea salt emissions internally considered by CMAQ (depending on wind speed)

7. BaP Emissions Available data:
Annual BaP emissions for 1970, 1975, 1980, 1985, 1990, 1993/1995, provided by Dr. Knut Breivik on the 50 x 50 km² polar stereographic EMEP grid.
Annual BaP emissions (in 5 sectors) based on TNO report for 2000 also on the EMEP grid
but: no temporal resolution available
Main sources are
residential heating
traffic
industry (steel and coke)
Annual, weekly and diurnal cycles need to be considered

8. Temporal cycle of BaP Emissions
season
Residential heating:
depends on season
Traffic:
depends on working times
Industrial emissions:
depend on working days
week
day

9. Example BaP Emissions (1)
Based on 1993/1995 annual emissions

10. Example BaP Emissions (2)
Based on 2000 annual emissions

11. Model Results (1)
Jan /July 2001 based on 1995 emissions

12. Model Results (2)
Monthly concentrationmeans of 2001 based on 1995 emissions in North Sea areas

13. Wet deposition
1995 vs 2000 emissions

14. Comparison to measurements - January
blue: 1995 emissions
red: 2000 emissions
black: measurements
(monthly means)

15. Comparison to measurements - July
blue: 1995 emissions
black: measurements
(monthly means)

16. Summary and Outlook
First results of BaP simulations with CMAQ look promising
BaP emissions need improvement ( incl. ship emissions)
Reconstruction of BaP concentrations 1970 –2000 based on EMEP emissions
Include other POPs (eg. PAHs, PCBs, PFOS)
Include second nest simulations

17. Partitioning

18. Measured size distributions

19. Simulated particulate BaP concentrations
Aspvreten
Kosetice

20. Simulations vs. ground measurements
Measured mean
Model mean

21. Simulations vs. ground measurements
Model mean
Measured mean

22. Simulated particulate BaP concentrations in September 2001
Bornhöved
Zingst

23. Simulations vs. ground measurements

24. Simulations vs. ground measurements

25. CMAQ in a ´very small´ domain
Run CMAQ on a 1x 1 grid to investigate processes
Example: BaP wet deposition under predefined conditions:

26. Nitrogen deposition into the North Sea

27. Nitrogen deposition into the North Sea: influence of meteorological fields
control run /
shallow convection run

28. Adsorption to dry surface
Φad adsorbed fraction of compound
c Junge parameter
θ surface of adsorbat
pL subcooled liquid vapor pressure

29. Absorption into organic matter
Φab absorbed fraction of compound
Kp gas/particle partitioning constant
Kp octanol/air partitioning constant
fOC fraction of organic carbon
TSP total suspended particles mass

30. Absorption into aerosol water
Φaq absorbed fraction of compound
Kp gas/particle partitioning constant
Kp water/air partitioning constant
fOC fraction of aerosol water
TSP total suspended particles mass

31. Simulated gaseous BaP concentrations in September 2001

32. Total simulated BaP depositions in September 2001

33. Interest in long term runs / use of met. fields from other models
Meteorology
Meteorological fields are calculated with MM5
Boundary Layer:
MRF (Hong and Pan, 1996), based on Troen and Mahrt (1986) nonlocal diffusion concept.
Microphysics:
Reisner 2, incl. ice, snow and graupel (Reisner et al., 1998).
Cumulus:
Kain Fritsch 2, conservation of mass, thermal energy, total moisture and momentum (Kain and Fritsch, 1993)
Interest in long term runs / use of met. fields from other models

36. Processes
BaP is emitted as accumulation mode aerosol (with 0.1% in Aitken-mode)
Gas-particle partitioning considering three aerosol modes (Junge-Pankow concept)
Dry deposition, scavenging and wet deposition as for aerosol particles in CMAQ
No photolytical and chemical degradation so far