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Is CDPHE Cooking the Books on Colorado Ozone? [Update]

Is the Department of Public Health and Environment cooking the books on Colorado ozone? Without explanation, CDPHE plugged 2006 meteorological data into the models it used to project ambient air concentrations of ozone. That’s suspicious, because 2006 just so happens to be the second worst year of Colorado wildfires on record.

According to the 2015 and 2020 Ozone Projections for the Denver Area (p1-4), “For the 2015 and 2020 modeling, both biogenic and fire emissions were held constant at 2006 levels, and were the same as what was used for Denver ozone state implementation plan 2006 and 2010 modeling.” Yet the report doesn’t note that 2006 was an anomalous year for wildfires. I wonder why not? It’s certainly germane, because the scientific literature demonstrates that more wildfires mean more ozone and more ozone precursors.

To be clear: I don’t know how (or even whether) using the 2006 input data impacts modeled ozone projections. And I will likely never find out. CDPHE paid for the modeling by a private environmental consulting firm (ENVIRON), for which the model is proprietary. That is, ENVIRON can keep it secret, even though the model was paid for with taxpayer money. Today I’m sending an email to the lead author of the models, ENVIRON’s Ralph Morris, asking about the implications of using the 2006 data. I will update this post if he responds. In any case, I find it remarkable that the report doesn’t even mention that wildfires were especially bad in the year that was chosen to be an input into the ozone model.

This could be a big deal. The Clean Air Clean Jobs Act (HB 1365), legislation that incents Xcel to switch from coal to natural gas, was sold by the Ritter administration as a necessary evil in order to avoid Big Brother. The first paragraph of the law states that purpose of the legislation is to meet “reasonably foreseeable” federal air quality regulations. As is explained here, the threat of pending federal regulation was grossly overplayed by the Ritter administration in order to lend impetus to the bill.

Now I am starting to suspect that I underestimated the lengths that the Ritter administration went to promote fuel switching. A federal crackdown on ozone was essential to the Governor’s case for HB 1365. Yet this warning was predicated on CDPHE’s models that may have been unduly biased by the use of input data from an anomalously fiery year.

Stay tuned….

[Update–Below is the email correspondence between Ralph Morris, the lead modeler, and me. To his credit, he responded very quickly and politely, even though it has been months since he worked on the modeling. He allows that using the 2006 input data is “conservative” in that it tends to overestimate the ozone data, and also that ozone could be lower than the projections if wildfires in future years are not as great, although it remains unknown by what magnitude.]

From: William Yeatman
Sent: Wednesday, November 10, 2010 11:41 AM
To: Ralph Morris

Greetings, I have a question re: “2015 and 2020 Ozone Projections for the Denver Area.” Given that 2006 was the second worst year of wildfires in Colorado history, are 2010, 2015, and 2020 projections of ozone affected by the fact that fire and biogenic emissions were held steady at 2006 levels? Would it make a significant difference if they were held steady at 2005 levels, a less anomalous year for wildfires?

Best, William

From: Ralph Morris
Sent: Wednesday, November 10, 2010 2:55 PM
To: William Yeatman

From what I remember, the high ozone concentration episodes in the Denver area during June-July 2006 were not that affected by wildfires so we don’t think they played a big role.  This is in contrast to the 2002 modeling we did for the EAC SIP where there were some episode days with wildfire influences.

Even if wildfires did have an influence by holding them constant we are being conservative in the attainment demonstration modeling.

Ralph

From: William Yeatman
Sent: Wednesday, November 10, 2010 12:10 PM
To: Ralph Morris

Greetings Ralph,

Thanks for responding so soon.

Would you be willing to briefly explain why holding them constant at 2006 levels would be conservative. It seems to me that if you hold those inputs (ozone, NOx, and VOC emissions attributable to wildfires/biogenic) constant at a year in which they were higher than normal, they would inflate the projections. Is that wrong?

Again, thanks for taking the time to respond.

Best,
William

From: Ralph Morris
Sent: Wednesday, November 10, 2010 3:38 PM
To: William Yeatman

William,

By “conservative” here I mean tending toward overestimating ozone levels in 2010.  In this context we are talking about the 2010 attainment demonstration modeling in the 2008 Denver ozone SIP where the modeling demonstrated that Denver would achieve the 1997 ozone NAAQS (0.08 ppm) in 2010.  If wildfires in the future are lower than they were in 2006 then ozone could be lower, but still demonstrated attainment.

Hope that explains what I meant.

Ralph