by Thomas Cahill
Charles B. Salocks, an expert on methamphetamines, has made a number of statements in Sunday’s Enterprise that deserve comment;
- Rest of I-80?
False. I made measurements for New Harmony that agreed with models to show minor impact south of I-80 (my report to Davis Planning, City of Davis New Harmony report 2014, Emfac2007).
ARB model Emfac2007 gives about a 500 foot no build zone north of I-80.
- Wind?
The highest exposures to diesel soot and ultra-fine metals at Nishi are in extended winter stagnation periods with a generally west to east drift impacting all of 
Nishi, when wind roses are useless. (Cahill et al 2014)
The afternoon Bay Breeze in summer crosses the overcrossing in the late afternoon when congestion and braking are maximum.
Virtually any wind direction exposes Nishi to either I-80 diesel and ultra-fines from braking (the final neck down of I-80 is south of Nishi) or railroad soot.
- Elevation
False. Data from as long as 40 years ago (Feeney et al 1976) as well as our work (Cahill et al 2016a) show the worst impact from elevated freeways.
The official ARB Emfac2007 and the new Emfac2017 show that most of Nishi is in the no build zone.
This information was used in the Davis DEIR, which found “…significant and unavoidable” (4.3-33) …” air quality impacts based on existing state and federal air quality regulations. This result was supported by measurements of diesel soot.
That EIR is now final, and it alone should block Nishi 2.
- Duration of exposure
We have no right to enforce permanent damage to student lungs (Gauderman et al 2002)
Asthma is instantaneous
Every day the student leaves to pick up their bikes, their handle bars will have a coating rich in benzo[a]pyrene from diesel soot. Train diesel soot is almost 6 times more toxic in heavy PAHs that truck diesel (Cahill et al 2011)
Pregnancy impacts require just a few months (UC Davis MIND Institute)
Indoor air
I have provided the developer with Davis developed state of the art ultra-fine filters that are better than anything you can buy. Use them!
However, even with our filters, we never got better than 75% in active buildings – Arden Middle school (Cahill et al 2014) or the San Bernardino BNSF railyard (CA Dept. of Toxics report).
- Vegetation
My data was taken from wind tunnel studies where air was forced through redwood branches. (Breathe California Final Report 2013)
Out field tests on 35th Ave and I-5 had an enormous roadway edge redwood barrier and only gave minimal relief within a few hundred feet. (Cahill et al 2016a)
Canopy vegetation does get relief by a factor of 2 but 15 years in the future, (Baldauf et al 2015, Cahill et al 2016a) but it is useless in winter when exposures are highest. (Cahill et al 2013)
- Tree canopy
See above, in 15 years, summer only.
- Cold start?
Old data. Very little impact from modern cars
- Worst freeway?
The elevated section of I-80 results in pollution 1,000 feet downwind that is almost exactly as at the roadway edge (Cahill et al 2016)
The regional PM2.5 at Yolo and Ontario (Glendora site) are almost exactly the same, 9.5 µg/m3. (ARB iADAM)
Nishi has more braking upwind, poorer ventilation in winter and train diesel, all of which are more severe at Nishi than Hwy 60.
In summary, my opinions are supported by my 50 years of air quality work much involving cars, trucks and freeways, work supported most recently by the US EPA in Detroit and Cleveland. (Cahill et al 2016 b)
Based upon these results, the EMFAC2007 table distances must be multiplied by a factor of ~ 20 for the same health impact (Cahill et al., 2016).
These data were taken downwind of a massive ~ 60 feet high solid redwood barrier . In summer, once you get beyond about 500 feet, elevated freeways even with a massive vegetation screen have almost the same concentration as at the road edge. The average data from 600 ft to 1,300 ft were used for the Nishi exposure calculations, ~ 89% of roadway edge.
Winter with good ventilation is better but rises beyond 1,000 feet. No data were taken in stagnation conditions.
Thomas A. Cahill, David E. Barnes, Leann Wuest, Sean Barberie, David Gribble, David Buscho, Jason Snyder, Roger S. Miller, and intern Camille De la Croix, Artificial Ultra-fine Aerosol Tracers for Highway Transect Studies, Atmospheric Environment 136, 21 – 42 (2016)
Some of Dr. Cahill’s statements are true as written, but not necessarily applicable to the Nishi site.
1. “Asthma is instantaneous” – absolutely true, but epidemiologically not shown to be significantly increased for the geographically closest residential areas to the Nishi site.
2.”Pregnancy impacts require just a few months (UC Davis MIND Institute)” – true as written for some toxins as witnessed by the well known effects of alcohol producing fetal alcohol syndrome even with brief exposure. Unknown for the type and quantities of toxins that women might be exposed to at Nishi. But more importantly, with the student only model of Nishi 2, unlikely to be applicable to this population. Pregnancy is unusual amongst UCD undergrad students, and the option of moving upon decision to become pregnant or discovery of an unintended pregnancy remains a possibility. All potential occupants should be informed of the concerns, but availability of housing for many should not be blocked by the theoretical concerns for a few which is the current state of the pregnancy related concerns. And yes, this is my field of expertise, but I did not rely on my own knowledge and consulted with a perinatologist who confirmed my impression.
It does not take 15 years to create an effective vegetative barrier if you design the planting for that purpose and choose your plants correctly with high growth rate and planting density. “Summer only” presumably refers to the use of deciduous species. The Nishi urban forest will contain 80% evergreens, selected primarily for effective leaf morphology, fast growth rate, and some with resinous foliage which makes them more effective.
The illustrations I have seen of typical vegetative barriers, including the one referenced above, appear to be about 30’ wide and comprised of a single row of trees. The Nishi urban forest would be 100’ deep and have additional plantings, if possible, in the 30’ CalTrans easement, as well as further plantings directly behind in the parking area and plants around the residences providing additional mitigation.
Per Dr. Cahill himself:
“At very low wind velocities, the vegetation can capture very fine and ultra fine pollutants by deposition before they leave the freeway right of way.
•This is especially effective when inversions are present.”
I found the opening line by Cahill rather telling.
Mais, oui…
“The afternoon Bay Breeze in summer crosses the overcrossing in the late afternoon when congestion and braking are maximum.” If Dr. Cahill understood traffic patterns in Davis, he would know that this statement is only generally true on Friday afternoons due to Tahoe traffic headed from the Bay Area. During the rest of the week, this traffic backs up only to a little past Mace (near New Harmony of all places…) In addition, during the summer, the Nishi complex will be largely empty as UCD offers few summer classes. The total population exposure will be greatly minimized.
As of the wind rose not being relevant, that patently false because the amount of time that the exposure occurs is highly relevant–is the exposure 365 days/year or 18 days/year? The wind rose tells us that.
“The elevated section of I-80 results in pollution 1,000 feet downwind that is almost exactly as at the roadway edge ” Why isn’t Dr. Cahill calling for an immediate emergency evacuation of all Davis residents living within 1,000 feet of I-80 and the rail line? And why isn’t Davis a cancer and asthma hot spot with elevated mortality and morbidity? His selective bias undermines his professional opinion.
Nah… you are dealing in facts… pasta trumps facts… [BTW, good post, good points]
It is interesting that Dr. Cahill quotes studies from the early 70’s decades before most people in town were born and 99% of the cars on the road did not have catalytic converters and CA did not have a smog check program. Dr. Cahill may want to look in to this and he will learn that the air around freeways is a LOT cleaner than it was in 1973 and 1974 (even if you ignore all the electric and hybrid cars). As more people point out that there is no “toxic soup” and laugh out loud at a study looks at freeway air from the Nixon Administration that said college kids will move to the site and stay for 70 years (when less than 5% of the populations is even still alive 70 years after they moved out of the dorms) I expect that we will see the people who have been pretending to care about air quality plant some Patwin artifacts on the site and move to “plan b” to try and stop any new development in town.
P.S. I’m wondering if any of the people (like Ron) that keep calling for more air quality tests at the Nishi site have ever tested the air quality outside their own homes (if not, I’m wondering why they care about the air rich UCD kids from the Bay Area might breathe in a few years more than they care about the air their family breaths every day)?
Yes… some of the posters should have their residences checked for asbestos and/or radon… or old pesticides used on the property they inhabit. All involve air quality and health.
I say this as someone who had Dr Cahill as a prof, and respected him… damn good teacher in the 70’s…