The document discusses the effects of increasing vertical diffusion from 2 to 10 m^2/s in the urban area of Beijing based on simulations from the European Centre for Medium-Range Weather Forecasts. Increasing diffusion in the urban areas led to a decrease in nitrogen oxides (NOx) and an increase in ozone (O3) according to the simulations. The study examines the impact of emissions on air quality by modifying diffusion coefficients in the control and test runs.

4. •
•
•
•
•

5. 20x20km

8. EUROPEAN CENTRE FOR MEDIUM-RANGE WEATHER FORECASTS

11. Do emissions matter?

12. Do emissions matter?

14. •
•
•
•
•

15. PBL Height
Diffusion Coef. At 18:00 Diffusion Coef. At 19:00

16. Effect of increasing diffusion in the urban area of Beijing
CNTRL: Control
run (2 m2 s-1)
TED: run with
increased vertical
diffusion from 2 to
10 m2 s-2

17. Increased
diffusion in urban
areas leads to
decrease in
NOx
increase in O3

23. •
•
•

24. •
•
•
•
•
•
•
•