Moderator: Mario Molina, MIT
Speakers: Greg McRae, MIT and Francisco Guzmán, Instituto Mexicano del Petróleo

Presentation by Professor Greg McRae

Professor McRae discussed air pollution generally and control strategies in particular, then outlined the principles of an integrated assessment. He reiterated the goal of the workshop: the effort to develop a US-Mexico model to address air pollution problems, a model which then can be applied to other cities around the world.

Air pollution on local, regional and global scales

Prof. McRae described two distinct forms of air pollution: gas phase and aerosol. Only a handful of gas phase pollutants are currently regulatede.g., in the US, ozone, SO₂, NO₂, and CO. Aerosols also have only a few regulations, primarily dealing with visibility. Given that thousands of chemical compounds are involved in air pollution, determining which affect human health and the environment, then devising strategies to control them, is the challenge to meet.

In the US, 70 million people are affected by ozone pollution. Although $30 billion is spent per year on controls, reductions have been minimal. And despite enormous public efforts directed at controlling ozone, there are many other pollutants with serious health and environmental consequences. CO₂ and other greenhouse gases have global environmental impacts; CO, NO_x and organic emissions have urban scale consequences; and particulate pollution and SO_x are largely regional problems (see Figure 2-1). But given that combustion is a common source for all these pollutants, a holistic approach would be more efficient. The question is how to achieve this.

Figure 2-1. Urban, regional and global emissions from fuel combustion.

Public perception and politics are important. He illustrated this with a slide of a power plant in New England with a visible steam plume going in one direction towards Canada while the pollutants emitted from a different stack went another direction. These pollutantsNO_X, SO_X, and CO₂are the products we should be concerned about. The difference in visibility requires that the public aspects of air pollution be carefully managed. He also commented on the international dimensions of pollution politics. One of the methods used to reduce regional and urban concentrations of pollution is to build taller stacks. While this reduces local impacts, it also introduces the possibility of transport across international boundaries. The acid rain problem in the United States is an example of how air pollution becomes an international problem.
Prof. McRae listed several common characteristics of air pollution problems:

• Decisions must be made even in the face of uncertainty.
• Good decisions require the expertise of multiple disciplines, among them engineering, economics, and political science.
• Public education and professional training are needed to increase the number of people who understand the issue at all levels.
• Technology is an important part of the policy solution, especially regarding fuels and combustion.
• Organizational barriers must be overcome.

Under ideal circumstances, interactions between science, technology and policy would flow in all directions. In reality, decisions are often made in isolation. Political pressure to act results in the uncoupling of scientific research and policy formulation. To control acid rain, for example, the US spent a billion dollars on scientific research. Most of this money funded research of interest to scientists, with negligible amounts devoted to integrating research with policy options. Little cost effectiveness analysis was conducted, nor were impacts of pollution beyond acid rain analyzed. In consequence, acid rain policies were effectively drafted without scientific input.

A similarly narrow focus characterizes atmospheric modeling, which relates emissions to actual air quality. Most models use emissions inventories, meteorology and knowledge of atmospheric chemistry as inputs, and yield information about resulting air quality. Typically these models deal with one phase, either gas or aerosol, and serve as a means for setting the emissions to attain a given air quality goal. What we really want, Prof. McRae said, is a broader view that also analyzes control systems, incorporating societal goals and environmental impacts. Such an approach would incorporate the distinct economic and political processes that characterize the problem, and acknowledge natural variability and noise.

The purpose of modeling, Prof. McRae said, is to avoid experimentation. Without a model, the only way to evaluate and experiment with policies is to actually implement them and monitor the results. Modeling gives us a method to analyze responses to change without first needing to implement the policies. Modeled results can then be used to act as further input for the design of control systems. By using such an iterative method, the likelihood of implementing a successful control strategy markedly improves.

Integrated Assessments

Prof. McRae defined integrated assessment: "To understand and integrate the component parts of a problem with an overall objective to implement cost effective solutions over time..." Its three componentsanalysis, synthesis, and outreachmust each provide feedback to the others.

Analysis attempts to understand the problem from a multidisciplinary and historical perspective. With air pollution, this would consider the health issues driving the need for intervention, the scientific problems, assessment of previous efforts, the regulatory structure, interest groups, and identification of policy options.

How to characterize emissions, the role of new instrumentation, and new analytic tools such as inverse modeling are examples of some key scientific issues. Prof. McRae identified Tunable Laser Diode Spectroscopy as an example of a new technology that can provide better estimates of actual vehicle emissions. With better data, a better statement of the problem can be formulated. And, by incorporating new decision variables and different decision-making algorithms, new options and policy proscriptions can be devised

Synthesis assembles these separate pieces into a coherent and viable program. Evaluation and analysis of different aspects of the problem are incorporated into the design of new control strategies that can bring new technologies, regulatory structures and resources to bear on the problem. In this step, one of the goals is to reduce the uncertainty in the decision-making process by bringing different skill-sets to the issue. Some examples of research on regulation and control strategies at MIT include market- and incentive-based schemes, risk-based regulation in the presence of uncertainty, integrated regulation across media and trading mechanisms. The goal is to allow the process to be actively shaped by stakeholders so that the "victim" aspect of the regulatory process can be eliminated.

The goal of Outreach is the successful implementation of the strategies developed through analysis and synthesis. Outreach is designed to build community consensus for the regulation as well as to expand the number of people trained to make these types of decisions. The aim is to establish an educational and evaluation system so that the process can be improved and its effectiveness appraised. Technology can help here, allowing computer generated maps and animation to explain science to the non-scientist. Prof. McRae demonstrated an animated model used in Los Angeles as a way to explain pollution strategies.

Education must also be directed at scientists and policy makers. For the Mexico City Project, a number of educational programs have been proposed to increase the flow of human capital and knowledge between the United States and Mexico, as well as between the scientific and policy-making communities. Activities such as short courses, visitor exchange programs, and collaborative measurement campaigns could be pursued.

In addition to the direct outcomes of the integrated assessment, Prof. McRae expressed the desire to provide a neutral forum for discussion of policy issues, and to develop stronger relationships between the participants in these discussions. The Mexico City Project would have joint US-Mexico executive and advisory committees, and project management to support communication and collaboration. The focus would be cost-effective strategies for mobility and fuels, power generation, land use planning, and technology options. Scientific, technical, economic, institutional and social issues would be integrated by involving different groups, departments, and links with interdisciplinary programs.

In conclusion, Prof. McRae said that the project would be deemed successful if its methods can be used by other cities to combat the global problem of air pollution.

Figure 2-2. Emissions-air quality relationships

Figure 2-3. A broader viewmodeling as part of a control system

Presentation by Dr. Francisco Guzmán

The Mexican Air Quality Research Initiative (MARI)

The Mexican Air Quality Research Initiative (MARI) (1990­1993) project was an integrated assessment sponsored jointly by IMP and the US Department of Energy (Los Alamos National Laboratories was the primary participant representing DOE). Its aim was to go from a portfolio of control strategy options to a coordinated, effective strategy. The project was a typical science-oriented project, which was challenged to incorporate some integrated assessment aspects.

Elements of the project included monitoring, measurement and characterization studies oriented around ozone, and pollution modeling and simulation. For strategy options, MARI looked at cost and emissions impact, and included a linear optimization. By running simulations of strategies, researchers were able to add economic, social, and political factors to the decision analysis tree (Figure 2-4).

First, an objective analysis was performed: quantitative information with respect to each control option was established, including reductions and cost, and current vs. target pollution levels were identified. This information was used in a linear programming model. Later, a non-linear approach was used, which showed NO_x effectiveness to be worse when considered in terms of annualized cost for percent ozone reduction (Figures 2-5a, 2-5b, & 2-5c).

The decision analysis tree was based on decision theory technique. There were four branches, representing technical, economic, social/political/institutional, and environmental issues. Under each issue area, multiple attributes were assessed and assigned weighting factors based on subjective analysis by people specifically chosen for their expertise (see Figure 2-6).

No explicit health effects were represented in the decision analysis tree. Dr. Guzmán remarked that when the project began in 1991, scarce data were available on health effects in Mexico City, so the issue was reflected through the air quality index only. Later, the tree was modified by adding an explicit health effects branch, but no weighting factors were used.

Using this approach, only 37 control options had sufficient information for the methodology, and more than 30 were analyzed. Out of these, 21 were chosen for final grading.

Dr. Guzmán said that the five-volume report of the MARI project is available on the Los Alamos web site. These include the executive summary and four technical volumes. The last volume is the strategy evaluation. Dr. Guzmán concluded that the MARI project is the only integrated assessment project to assemble scientific, technical, and social/economic aspects under one umbrella.

Discussion Summary

The discussion addressed aspects of integration, evaluation, community input and public perception, and how to accommodate social criteria, as related to the MARI project, to Mexico, and to integrated assessments in general. Comments on the goals of the Mexico City Project reinforced the need to focus on identifying barriers and producing a set of issues for research and examination, rather than trying to formulate a comprehensive and immediate solution. The MARI project provided some perspective on conducting large, integrated projects. Asked what he would do differently if he had the whole project to do over again, Francisco Guzman replied that he would keep the expert panel meeting as a means of maintaining dialogue between diverse groups.

How to address "soft" issues was the subject of much discussion. MARI is a specific example of an integrated assessment based on optimizing multiple weighted objectives, but this is only one model. Another might approach it as a "coordinated assessment" rather than a mathematical optimization around one variable. One suggestion was to think about integrated assessment as a mechanism to produce sets of issues that can then be evaluated from different perspectives (political, economic, scientific, etc.), providing an appraisal of the advantages and disadvantages for different sectors of society. With the understanding that there is no single way to view the data, analysis should serve to spark discourse and feed the broad debate rather than attempt to provide a final answer.

Bringing in perspectives from different sectors also helps to broaden the debate of control strategies, as does looking at approaches used in different countries. For example, one means of addressing air pollutionand at the same time other problemsis to build industries and create jobs away from major cities in order to stem the tide of growing urban population. Expanding the view beyond technical strategies stimulates "out of the box" thinking about solutions that might involve, for instance, land use planning or mobility strategies. The integrated assessment will get to the broader issues by encouraging these ideas. Indeed, this project goes beyond dealing just with ozone (which was the sole focus of MARI).

The discussion addressed how to integrate other issues, such as particulates, climate change, land use, etc. Global warming is one area in which there is an understanding that complicated problems cannot be solved solely by one discipline, but need a broader view. However, there is no clear method to accomplish this, and limitations exist given the different institutional frameworks for addressing local, regional, and global issues. For example, in Mexico City the emissions inventory is currently coordinated by the Metropolitan Commission, but the federal government keeps the inventory of point sources, and there is a lack of coordination between the two agencies. The national greenhouse gas emissions inventory is produced by a mixture of bottom up and top down, but has many holes. At a high level of abstraction (e.g., using GNP weightings to parcel national emissions to particular areas), the inventories become very inaccurate. The lack of reliable emissions inventories that are robust enough to be used for different levels of analysis is a barrier to integrated assessment. How to address these limitations and barriers would be appropriate questions for further research.

However the assessment is constructed, we need to be thoughtful about how to handle the social dimensions. Criteria are often intangible and not measurable, and there may not be enough information to quantify the social aspects of the problem. An alternative model might allow accounting for social issues without actually quantifying them. In reality, tradeoffs between criteria such as fairness, equity, and cost effectiveness are a significant factor in the perception of and actual implementation of policies. The risk is that policy makers make decisions about these tradeoffs implicitly, without taking all of these factors into account unless there is an ongoing panel of experts making these intangibles explicit and keeping them in the debate.

One experience of the MARI project highlighted this. As part of the decision analysis, the project provided a forum for policy makers at the highest level to exchange ideas and discuss weightings for evaluation. Closing the refinery near Mexico City was never even considered as a viable option because it was too expensive, and cost was heavily weighted. Yet the President of Mexico subsequently closed the refinery unilaterally, which yielded a very positive effect. Obviously, the "experts" got the weighting wrong, and overlooked the priorities of the most important personthe President. The involvement of the President gave credibility to the action and forced others to think about such possibilities. Participants still thought it was useful to have representatives from different sectors exchange ideas, but the outcome in this circumstance illustrates one of the dangers of relying exclusively on exercises that reduce everything to numbers and rankings.

Another problem with expert weighting schemes and optimization techniques is that even with a reliable set of input data, results can be invalidated once the community learns of the subjective weightings used and where they came from. Education needs to happen early in the process so that public perceptions are not at odds with scientific findings.

One lesson is that there are no "right" answers. Rational analysis is a useful tool but it must be recognized that any weighting scheme represents a particular group. In reality, politics requires that decisions be made in the context of different groups with different priorities. A good policy process should have feedback loops to integrate different perceptions into the analysis, and should recognize that even given the same science, the answer for one city might not be the same as the answer for another.

It was pointed out that how different communities (government, scientific, public) construct the problem frames how they approach potential solutions. This construction of the problem is crucial; the solution is not just a technical matter of scientific findings, but requires putting them into practice in the political, economic, and social context in which the problem is framed. Even in scientific communities there isn't consensus, so it is particularly important to take different forces and priorities into account.

There was general concern that integrated assessments might not adequately take into account community input, and discussion about the need to involve the community in addition to including experts from different sectors. The MARI project included a public acceptance telephone survey, but it was minor in the context of the whole project. Some cited the lack of government efforts to involve the community during the developmental phase of programs and policies as a problem based in Mexican culture. Many comments reinforced the importance of taking public opinion into account better.

It was also pointed out that community outreach is important in order to get politicians to fund inventories and monitoring programs. Politicians need to understand the problem so that they can buy into a potentially difficult or costly solution, and public support is important to get resources allocated. Community outreach should happen all along the process of generating data and developing solutions.

The role of public perception was discussed as an important but complicated issue. People get information in different ways and many don't really understand the problem. For example, many ordinary people in Mexico City think they can smell and see ozone. Most of the information they get about air pollution comes from mass media, but how do the media deal with these issues? In general, they are not educated about air pollution either. Even considering what people learn in school, the level of knowledge is low. Given the lack of opinion polls assessing what people understand, we may be guessing when we refer to people's perceptions. For instance, if Mexico City were classified according to the scheme in the US Clean Air Act Amendments of 1990, it would be a "severe non-attainment" area, which is given 20 years to develop a solution. But ordinary citizens don't realize that this is how complicated and difficult the problem is. They expect it can be done sooner, and they want the government to fix the problem without making them leave their cars. To address these issues, some suggested there be an effort to gauge what people really know. And, since the media do educate the public, one service the project can provide is to make sure that the media report it correctly.

Participants recognized that the job is not done once policies are implemented, and discussed aspects of evaluation. MARI made a general assessment of the control program (the city government fully implemented all of the strategies suggested in the MARI project as well as some additional measure that were not originally assessed). The initial assessment of the control measures indicated a 10 to 20 percent reduction in peak ozone events relative to 1991 levels.¹ A similar reduction was observed, indicating the assessment was correct.² However they didn't evaluate the performance of specific strategies. For instance, emission reduction goals were based on all of the options being fully implemented, but somelike having all cars fitted with catalytic convertershave not happened yet. Strategy evaluation requires a good emissions data, and evaluation of the emissions inventor itself was also discussed. Older emission data had a lot of uncertainties, but now the inventory is better.

Evaluating implementation and effectiveness of specific strategies would yield useful information. Yet even in the US little evaluation is performed. Although Los Angeles has spent large sums of money on control, relatively little has been spent on analyzing trends or assessing the effectiveness of its programs. It would be informative to compare Mexico City's progress to Los Angeles, where there are more people and more money devoted to the problem. In general, evaluating whether control strategies are working is very important and should have more resources devoted to it. Coming up with some methods to better compare the effectiveness of different programs would be a good contribution that the project can make.

In sum, participants acknowledged that there are no magic solutions, and successful strategies need time and effort. The project's intent is to contribute to the process. Evaluating what has been done in the past is important, as is educating people around this issue. The integrated assessment should deal with how to interact with the media and craft a strategy for public participation. The cultural basis for the issue, particularly with respect to public participation and decision making in Mexico, needs to be better understood. Finally, the issue of trust is very important. This project has no political stake. It aims to be neutral, and to provide a discussion forum which is neutral, and so has tremendous possibilities.

Footnotes

1. It was pointed out, however, that even if emission reduction goals were fully realized, it would not be enough to achieve the standard.
2. For example, typical IMECA values (for peak events) in 1991 were between 280 and 290, and in 1995 they were around 240 to 250.