The Mexico City Air Quality Case Study

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IUAPPA-IPURGAP Reducing the Impact of Vehicles On
Air and Environmental Quality in Cities January
22-23, 2004
The Mexico City Air Quality Case Study Mario J.
Molina and Luisa T. Molina Massachusetts
Institute of Technology
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Topographical Map of the MCMA

• Population Growth
• 17.5 million (1999) 20-fold increase since 1900
• Growth projection to 25 million (2010)
• Urban Sprawl
• 1500 km2 (1999) 10-fold increase since 1960
• Expansion to peripheral areas
• Geographic and Topographical Conditions
• High altitude (2240m) less efficient combustion
  processes
• Mountains are a physical barrier for winds
• 2nd largest mega-city in the world
• Temperature inversions in the dry season
• Increases in Emissions Sources

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Expansion of the MCMA
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Trends in criteria pollutant concentrations for
the MCMA (averages of data at five RAMA sites
TLA, XAL, MER, PED, and CES)
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Trends in criteria pollutant concentrations for
the MCMA (averages of data at five RAMA sites
TLA, XAL, MER, PED, and CES)
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Integrated Program on Urban, Regional and Global
Air Pollution Mexico City Case Study (Mexico
City Air Quality Program) Objective Provide
objective, balanced assessments of the causes and
alternative cost-effective solutions to urban,
regional and global air pollution problems
through quality scientific, technological, social
and economic analysis in the face of incomplete
data and uncertainty - Use Mexico City as the
initial case study - Develop an approach that
applies globally - Build on strong base of
ongoing basic research
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A Framework for Integrated Assessment
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Collaborative Research and Education Program
Mexican Participants Universidad Autónoma
Metropolitana (UAM) Instituto Mexicano del
Petróleo (IMP) Petroleos Mexicanos
(PEMEX) Universidad Nacional Autónoma de México
(UNAM) Universidad de las Americas, Puebla
(UDLA) Universidad Iberoamericana (UIA) Instituto
Tecnológico de Estudios Superiores de Monterrey
(ITESM) Secretaría de Medio Ambiente y Recursos
Naturales (SEMARNAT) Instituto Nacional de
Ecología (INE) Centro Nacional de Investigación
y Capacitación Ambiental (CENICA) Gobierno del
Distrito Federal (GDF) Secretaria de Medio
Ambiente (SMA) Gobierno del Estado de México,
Secretaria de Ecología (SEGEM) Secretaría de
Salud (SS) Insituto Nacional de Salud Pública
(INSP) US Participants Massachusetts Institute
of Technology (MIT)Washington State University
(WSU) Montana State University (MSU) University
of Colorado at Boulder (UC) Lawrence Berkeley
National Laboratory (LBNL) Aerodyne Research Inc.
(ARI) Department of Energy/Atmospheric Science
Program (DOE/ASP) Argonne National Laboratory
(ANL) Pacific Northwest National Laboratory
(PNNL) Los Alamos National Laboratory
(LANL) Colorado State University
(CSU) Pennsylvania State University
(PSU) National Science Foundation
(NSF) University of California at Riverside
(UCR) National Center for Atmospheric Research
(NCAR) European Participants Chalmers University,
Sweden ETH-ZurichEcole Polytechnique Federal de
Lausanne University of Heidelberg Free University
of Berlin
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Summary of the First Phase of the Mexico City
Air Quality Program
Chapter 1. Air Quality Impacts A Global and
Local Concerns Chapter 2. Cleaning the Air A
Comparative Overview Chapter 3. Forces Driving
Pollutant Emissions in the MCMA Chapter 4. Health
Benefits of Air Pollution Control Chapter 5. Air
Pollution Science in the MCMA Understanding
Source-Receptor Relationships Through Emissions
Inventories, Measurements and Modeling Chapter 6.
The MCMA Transportation System Mobility and Air
Pollution Chapter 7. Key Findings and
Recommendations
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NOx Emissions (1998)
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PM10 Emissions (1998)
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Estimates of mortality impacts from particulate
matter, drawn from time-series studies worldwide
and in Mexico City
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Estimated Health Benefits of a 10 Reduction of
Pollution Levels in the MCMA
Background Rate
Risk Coefficient
Risk Reduction
PM10
(case-persons-yr)
(cases/yr)
( per 10µg/m3)
Cohort
10/1000
3
2000
Mortality
Time Series
5/1000
1
1000
Mortality
Chronic
14/1000
10
10 000
Bronchitis
Risk Coefficient
Background Rate
Risk Reduction
Ozone
( per 10µg/m3)
(case-persons-yr)
(cases/yr)
Time Series
5/1000
0.5
300
Mortality
Minor Restricted
8000/1000
1.0
2,000,000
Activity Days
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• Focus of the Second Phase of the
• Mexico City Air Quality Program
• Systematic development of scientific information,
  evaluation methodologies and simulation tools in
  the following areas
•  
• activities that lead to the generation of
  pollutants in the MCMA (transportation,
  production of goods and services, degradation of
  the natural environment, etc.)
•  
• dispersion and transformation of atmospheric
  pollutants (focus on ozone and particles)
•  
• evaluation of risks and the effects of pollutants
  on the population
•  
• cost-benefit analysis of control strategies
•  
• integrated assessment of policy options and
  priorities for control strategies
•  
• strategies for capacity building.

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MCMA-2003 Field Measurement Campaign Science
Questions

• Emission inventories
• What are the sources of NH3? HCHO? What are
  their emissions rates?
• Are hydrocarbon emissions underestimated? Are NOx
  emissions overestimated?
• Are there significant biogenic emissions, e.g.,
  terpenes?
• Chemistry transformation of emissions in the
  atmosphere
• How is the reduction in NOx and/or HC related to
  reduction in O3 and PM?
• Would reductions in NOx lead to a reduction in
  nitrate particulates?
• What is the impact of reducing ammonia?
• How much HCHO is primary vs. secondary (produced
  photochemically)?
• What is the partitioning of NOy (NOx, HNO3,
  organic nitrates)?
• What are the sources and the chemical composition
  of the fine PM?

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MCMA-2003 Field Measurement Campaign Science
Questions (cont)

• Meteorology
• What is the height of the mixing layer?
• How does it evolve with time?
• Is there any carry over of pollutants from one
  day to the next?
• Do the models satisfactorily predict wind speeds
  and directions?
• Urban-Regional-Global Chemical Transformation
• What are the effective source terms for emissions
  for global climate models?
• What are the roles of aerosols in modifying the
  local/regional radiative transfer processes
  and cloud properties?

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Ozone with 1-4 x HC emissions
Mar. 2, 1997
Mar. 14, 1997
Ozone concentrations are average of all
measurement sites.
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MCMA-2003 Field Campaign Supersite Instrumentation
Supersite Location CENICA (UAM-Ixtapalapa)

• Instrumentation
• CENICA - monitoring station, tethered balloon
• RAMA - monitoring station
• WSU VOC sampling
• DOE/ PNNL PTRMS, single particle
  sampler/analyzer, MFRSBR, RSR
• UCB/LBL Particle sampling apparatus
• DOE/Argonne National Lab PAN, black carbon,
  olefins, NH3
• Colorado U. AMS
• Penn State OH and HO2
• IMP MINIVOLS and MOUDI , aldehyde cartridges
• MIT/U. Heidelberg - DOAS
• MIT/ Free U. Berlin LIDAR
• MIT PAHs
• UCR nitro-PAHs, PAHs
• EPFL - LIDAR
• UNAM FTIR
• Chalmers FTIR, DOAS
• Plus others

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MIT/IUP DOAS equipment on Cenica Roof-top (Hut)
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Aerosol Mass Spectrometer (AMS) at CENICA

• 100 transmission (60-600 nm), aerodynamic
  sizing, linear mass signal.
• Jayne et al., Aerosol Science and Technology
  331-2(49-70), 2000.
• Jimenez et al., J. Geophys. Res.- Atmospheres,
  108(D7), 8425, doi10.1029/ 2001JD001213, 2003.

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Aerosol measurements (April 15-17, 2003)
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Mobile Laboratory Modes of Operation February 2002
Stationary Sampling High time resolution point
sampling Quality Assurance for conventional air
monitoring sites
Mobile Sampling/Mapping Motor vehicle pollution
emission ratios Large source plume
identification Ambient background pollution
distributions
Chase Detailed mobile source emissions
characterization Plume tracer flux measurements
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Formaldehyde Measurements February 2002
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• Environmental Education and Outreach
• Visiting Mexican scholars at MIT
• Workshops/symposia on air quality
• Professional development courses on air quality
  for mid-career personnel in the government,
  industry and academic sectors as well as
  non-governmental organizations and the media
• Masters Program in Environment and Health
  Management at MIT and Harvard School of Public
  Health (INE-MIT-Harvard joint program)
• Exchange program between MIT and Mexican
  institutions
• Establish the Research and Development Network on
  Air Quality in Large Cities in Mexico
• Web-based activities for senior high school
  teachers and students (with Monterrey Tech,
  ITESM)

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• MIT Scenario Analysis
• Integrating Bottom-Up and top-Down Analytic
  Approaches
• Three Feasibility Screens
• Technical Feasibility (effective)
• Economic Feasibility (affordable)
• Pursued through quantitative analysis
• Political Feasibility (implementable)
• Pursued through qualitative dialogue
• Feasibility depends in part upon the Future
  Story
• Allows us to identify more robust options

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A Diverse Mix of Emissions/Sources
Source CAM 1998 MCMA Emissions Inventory
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Increase in Automobiles per Capita in Mexico City
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Collaborative Activities with Latin American
Cities

• Air quality forecasting training workshops (with
  Santiago de Chile and São Paulo)
• Transportation/land use and atmospheric modeling
  and measurements (with Santiago de Chile and
  other Latin American cities)
• Inter-American Network for Atmosphere and
  Biosphere Studies (IANABIS)

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Fleet composition and operations

• Provide incentives to increase the turnover rate
  of the trucks, taxis, colectivos, and private
  auto fleets.
• Enforce existing regulations on maximum age of
  taxis and colectivos
• Develop incentives to encourage retrofitting of
  trucks with emission control devices.
• Continue audits of Vehicle Verification Testing
  Stations using on-road test data, and correct
  irregularities

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Public transportation

• Give priority to the organization of the
  transportation system
• at the metropolitan level, including the
  improvement and
• coordination of all the current modes of
  transport.
• Increase the use of the metro system by
  improving service
• quality, performance, and personal security.
• Facilitate inter-modal transfers to improve
  convenience and
• speed of public transport.
• Important origins and strategic destinations
  should be
• considered in the planning for the proposed
  expansion of the
• metro network.

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Infrastructure/Technology

• Develop infrastructure to enable intercity
  truck traffic to bypass the downtown core in
  order to improve air quality and reduce
  congestion.
• Evaluate the feasibility of implementing
  Intelligent
• Transportation Systems (ITS) to improve
  traffic management
• and thereby reducing pollution.
• Consider alternative transportation pricing
  policies, enabled
• by ITS, to reduce the volume of traffic and
  pollution.

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Fuels

• Establish new specifications with lower sulfur
  content in
• gasoline and diesel that enable the
  introduction of future
• cleaner vehicle technologies.
• Develop natural gas as a potential
  transportation fuel for
• urban buses and intra-urban trucks
• Prohibit illegal vehicle conversions to run on
  LPG without
• adequate emission controls

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Recommendations (short term)

• Improve enforcement
• Taxis lt 6 years old (DF), lt10 years old (EM).
• Microbuses lt7 years old
• Registration and license plates.
• Centralize VVP database.
• VVP certificates up to date/not counterfeit.
• Increase audits evaluations of VVP.
• Traffic regulations.

• Improve Data
• Establish reliable registration database.
• Improve trip data.
• Update traffic accounting data.
• Use remote sensing and tunnel tests to improve
  emission inventory.
• Make emission and vehicle data publicly available
  for new and used vehicles.

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Recommendations (medium term)

• Control Vehicle Demand
• Limit private vehicle use.
• Restrict taxi numbers through a permitting
  process.
• Regulate colectivos, but encourage their
  continuation.
• Create no private vehicle areas in DF.
• Discourage single passenger trips.

• Upgrade the Fleet
• Registration fees less age sensitive.
• Tighten VVP emission standards for older vehicles
  and inspect trucks (NOx, PM, PAH)
• Require vehicle retrofit (gasoline and diesel).
• Upgrade bus fleet.
• Acquire USA standards at only two year delay.
• Lower sulfur (gasoline and diesel).

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Recommendations (long term)

• Land Use Planning
• Establish a regional planning commission with
  authorities financial independence like SCAQMD.
• Generate a long term plan that is consistent with
  high mobility and low pollution.
• Enforce sanctity of land reserves.
• Develop and use a mobility/land use tool for
  planning.

• Public Transport
• Integrate colectivos with public transport.
• Promote multi-mode transport fares.
• Encourage park ride.
• Improve security and safety on public transport
  and in park ride lots.
• Give traffic preference to public transport and
  multi-person vehicles (dedicated lanes, etc.)