1. Air quality modeling in Mexico Basin Meteorology Air Quality Víctor Magaña Aron Jazcilevich Ernesto Caetano Augustin Garcia Joel Pérez Luiz Gerardo Ruiz Alejandro Zitacuaro Xóchitl Cruz Centro de Ciencias de la Atmósfera Universidad Nacional Autónoma de México Mexico City 04510

2. Domains used for operational weather predictions with MM5 at UNAM www.atmosfcu.unam.mx/cca

3. Data used For operational Weather prediction Radiosonde RAMA surface weather station + SMN surface weather station

4. Main interest on precipitation

5. However, other products are presented winds, temperature, surface pressure, humidity

6. http://132.248.8.60/~mm5v3/pcivil.html

7. For the first time a model such as MCCM is being used for urban planning of the metropolitan area of Mexico City. It is used to study the air pollution phenomenon in the region. The Multi-scale Climate and Chemistry Model (MCCM) is an air quality model based on MM5 and RADM2 photochemistry.

8. 111 124 137 150 0 0 0 8 21 34 47 60 73 86 99 112 125 138 151 0 0 0 9 22 35 48 61 74 87 100 113 126 139 152 0 0 0 10 23 36 49 62 75 88 101 114 127 140 153 0 0 0 11 24 37 50 63 76 89 102 115 128 141 154 0 0 0 12 25 38 51 64 77 90 103 116 129 142 155 0 0

9. Land-use

10. Emissions: Mobile: Based on TÜV study for 1993. Area: 26 categories Point Sources: 400 industries

11. NOx Emissions

12. Problems: Incomplete emission inventories especially in the Northern zones of the Metropolitan area Changing emission areas due to urban development Changing emission due to new technologies and gasolines

13. Challenge: Development of a traffic model capable of predicting mobile emissions in case of severe traffic disturbances (demonstrations, accidents, public works) Urbanization of the meteorological model (MM5) Especially surface layer schemes (First 50 to 500 meters)

14. Ozone Satistics Buena concordancia  o  m y  o  RMSD

15. Examples of Urban Planning From the point of view of atmospheric pollution, two different locations for the New International Airport of Mexico City together with their associated urban scenarios for year 2020 were studied. These locations were: Texcoco and Tizayuca

16. Options Tizayuca (left) and Texcoco (right) and their associated urban distribution

17. Pollution distribution for the two locations The modeling period chosen (October 29th- November 1st, 1996), is a typical high pollution scenario. The average distribution for different air pollutants for 48 hrs. for the two scenarios is shown:

18. Difference in concentrations between options Tizayuca and Texcoco O 3 NO x PP´s

19. Integral Potential Exposure Ψ for the urban scenarios Ψ measures the exposure in time and space, incorporating the number of population potentially exposed to outdoor hazardous levels of c i,j pollutants using the formula, where ω i,j,n is the population in cell i, j and ω max is the maximum population in the region. The Ψ´s obtained for the two scenarios and the present situation were:

20. Ψ´s for urban scenarios

21. The modeling results indicate a lower potential exposure to most pollutants for option Tizayuca. SO 2 may again become a serious pollutant in the region.

22. Regardless of the airport location, the air pollution situation for the central region of Mexico will deteriorate.

23. Air quality consequences due to land use change Land use changes can influence airflow patterns an therefore the air quality at a local level. MCCM was used to study this issue by constructing a “virtual lake” in Texcoco.

24. Different coverings next to possible new Texcoco Airport Airport + Desert Airport + vegetation Airport + vegetation Airport + lake Airport + lake

25. Lake-breeze effect for airport+lake option (February 26, 1997)

26. O3O3 O3O3 NO 2 PP’s HCHO SO 2 Potential exposure for different coverings

27. Air Flow Patterns Insights on the air pollution phenomenon in the central region of Mexico are provided by MCCM. Due to the complex orography, vertical circular wind flow patterns develop over Mexico City

28. Pattern for CO 09:00 LST March 2nd, 1997.

29. O 3 pattern

30. With MCCM it is also possible to visualize how pollution is transported to the Valley of Cuernavaca through Chalco

31. Surface wind flow and CO concentrations, March 4th, 1997.

33. Conclusions Air quality models such as MCCM are an important tool for urban planning for the Metropolitan Area of Mexico City. If no major emissions reductions are introduced, the air quality will deteriorate with the growth of Mexico City. The orography of the region produces intricate flows that influence pollution transport.

34. Neighboring valleys can be influenced by the pollution of Mexico City. Land use changes such as the recovery of Lake Texcoco can help mitigate pollution at a local level.