This editorial is the third in a series of discussions on seven areas of concern with the proposed Loop 202 South Mountain Freeway (SMF).

To begin the series, I discussed the fact that Protecting Arizona’s Resources and Children’s (PARC’s) chances of winning in court are extremely good because the Arizona Department of Transportation (ADOT) did a poor job studying the impacts of the SMF. For example, ADOT and the Federal Highway Administration (FHWA) are complicit in:

• Distortion of purpose and need for the SMF.

• Air pollution.

• Negative health effects — especially for children.

• Destruction of wells.

• Danger from hazardous materials.

• Desecration of South Mountain.

• Destruction of quality of life (noise, crime facilitation, home values).

In my second editorial, I began the discussions of each of the specific areas of issues with the SMF by discussing the distortion of purpose and need for the SMF. This discussion will be about the second topic, air pollution.

Many different pollutants affect air quality. In the Valley of the Sun, particulate matter (dust) is a major problem in addition to ozone and carbon monoxide. Another class of pollutants of particular concern are called mobile source air toxics (MSATs) — compounds emitted from highway vehicles — and these include formaldehyde, benzene, a bunch of compounds I cannot pronounce, and diesel particulate matter.

Diesel particulate matter is a significant concern for the SMF. About 5000 trucks cross the border at Nogales daily after filling their tanks with high sulfur content diesel fuel — available in Mexico but not in the U.S. These trucks could easily reach the SMF before refueling, so they would be spewing a high concentration of diesel particulate matter into the air near Ahwatukee. Although this type of highly concentrated pollution would have a significant effect on air quality, ADOT does not even consider it as a part of their air quality models.

ADOT does not admit that the SMF would be a truck bypass. In spite of much public outcry about the truck bypass, ADOT continues to insist that the SMF would have a “normal” distribution of vehicles — 10 percent would be trucks. Even if we were to use ADOT’s reasoning, the SMF would be filled to capacity within a short time. About 135,000 vehicles per day would use the SMF, and 13,500 of them would be trucks. Note how this differs from ADOT’s implication (through the video on their website) that the traffic on the SMF would be very sparse, with no trucks at all!

If we consider the SMF as a truck bypass, it is not unreasonable to expect more like 20 percent of vehicles to be trucks, or close to 30,000 trucks per day! Just imagine the pollution coming from all these diesel trucks!

ADOT has developed a narrative that makes it sound like all the above-mentioned air pollutants are decreasing at such a rate throughout the valley that no freeway could possibly make them worse. They have used models to “prove” this. While I do not doubt that these models are valid when used properly with appropriate input data, ADOT is not using them properly. As the old saying about computers goes, “garbage in, garbage out!”

ADOT has avoided studying air quality in Ahwatukee. They have given no indication that they know how the South Mountain “air shed” affects wind currents or air pollutants throughout Ahwatukee. With a prevailing wind that blows air pollutants from the south right up against South Mountain, it would be nice to have information about the present air quality in various locations in Ahwatukee, starting with locations close to the mountain and working south all the way to Pecos Road.

Yet, without any data about air currents or the present state of air pollution in Ahwatukee, ADOT claims to be able to predict that future air quality would improve in spite of the presence of a freeway through the area. The EPA says ADOT’s predicted decline in pollutants is not likely. As one who has spent a great deal of my professional life dealing with computer modeling and simulation, I reiterate what I said in the first of this series. ADOT has demonstrated an inability to use proper modeling techniques for projecting future conditions.

When modeling the air pollution resulting from the SMF, ADOT has picked inputs for their models from locations throughout the Valley that measure air quality. The EPA has found that ADOT tends to be inconsistent in selecting inputs for their models. The EPA report on ADOT’s Environmental Impact Statement indicates that ADOT confuses the overall study area (Maricopa County) with the area directly adjacent to the project corridor (the proposed freeway corridor). In other words, ADOT picks and chooses air quality inputs for their models from a variety of locations throughout the valley rather than using inputs from locations along the freeway. The result is that their models prove nothing about air quality along the proposed freeway route.

Air pollution is a second area in which PARC is well prepared to contest the SMF in court. Yet I still have five more SMF major problem areas to discuss.

On March 10, ADOT and the FHWA released the Record of Decision to build the SMF. Generally, there is an opportunity to appeal such an important decision, but ADOT shut that door. The bad side of this decision is that ADOT can begin planning/constructing immediately. The good side is that PARC does not have to waste time and money on an appeal. The lawsuit to stop the SMF will be filed very soon.

• Dr. Pat Lawlis is president of Protecting Arizona’s Resources and Children (PARC), a non-profit organization by and for the residents of Ahwatukee. She has a PhD in software engineering from Arizona State University and has been a resident of Ahwatukee for more than 20 years.

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