Tag Archives: secondary standard

EPA’s New Ozone Rule: Part 24

This last post about EPA’s new ozone rule will summarize the topic and will draw some conclusions. We begun with a September 2011 news item that the Obama administration had requested the EPA to withdraw a new proposal to reduce the maximum amount of ground-level ozone in the air:    from 75 ppb to 70 ppb (.075 ppm to .070 ppm)1. This decision stirred controversy with many in the business community praising the President for keeping economic concerns front and center against many in the environmental community claiming that the President had missed an important opportunity to improve air quality2. Our purpose was to determine which side held more weight.

The answer to that question depends a great deal on one’s sense of priorities: is a robust economy more important or is reducing sickness and death from air pollution to a minimum more important? We know that ozone is a respiratory irritant, lethal in high concentrations but damaging even in very low concentrations3. We have ample research that shows higher ground-level ozone concentrations causes more deaths and results in more visits to hospital emergency rooms and missed days from work4. On the other hand, minimizing ozone creation is an expensive proposition. Requiring industry, responsible for most ground-level ozone production, to reduce its ozone contribution is laying on it a heavy regulatory burden that hampers business activity and reduces employment5.

We discussed the origins and chemistry of ground-level ozone and saw why industry would need to bear most of the burden of lowering the standard6. We noted that the new rule actually imposed two standards, a primary standard based on highest averages to protect human health, and a secondary standard based on cumulative exposure to protect property and economic interests, particularly plant life7.

We talked about the damage that ozone does to people and property8, then went on to discuss the history of ozone regulation since 20089. We went into some detail into EPA’s thinking as recorded in government documents, trying to understand why they set the primary standard as .075 ppm in 2008 but .070 only two years later10, and why they originally did not really set a secondary standard but later formulated one on the insistence of CASAC (Clean Air Scientific Advisory Committee)11. We saw that the two administrators, Stephen Johnson under President Bush and Lisa Jackson under President Obama, had access to about the same evidence but came to very difficult conclusions about what was needed to protect the public health and leave an adequate margin for error12. We saw how CASAC strongly objected to not having a separate secondary standard and how they influenced the EPA to adopt such a standard in 201013. We discussed the burden of implementation and touched on the many industries that are effected by tougher ozone rules14. We did a very rough cost-benefit analysis weighing the financial benefits of stricter ozone regulation against its economic costs to society15.

Finally, we discussed how well current ozone rules are being implemented, what areas of the country are not in compliance with the current standard of 75 ppb, and by how much16. We saw that non-attainment of the current EPA standard is confined largely to the East and West Coasts and to major metropolitan areas. Only California has severe problems with ozone, and it has those problem in a large swath through the state. Baltimore and Dallas have moderate problems, and the rest of the country have at most marginal problems with ozone.

So where does that leave us? Should the EPA try to implement a stricter standard at a later date? President Obama himself stated in his September 2011 statement that the ozone standard would be reconsidered in 2013, so perhaps this year we will see a second attempt. But maybe not: Lisa Jackson left the EPA last February, and until the Senate confirms a successor, the EPA will be headed by an acting administrator (Bob Perciasepe). I understand that an acting director does not have the same authority as an administrator confirmed by the Senate, so I doubt that the EPA will adopt a stricter standard until a new Administrator is confirmed (Obama’s current nominee is Gina McCarthy).

I don’t disagree with Obama’s decision to request a retraction. Business opposition to the new rule was strong. He was facing a difficult election and he didn’t need to stir up more opposition than he had to. As we discussed earlier, deciding whether the ozone standard should be at 75 ppb or 70 ppb is largely a judgement call. The lower standard will save lives, increase life expectancy, and relieve illness, but will likely be an economic burden and an impediment to job creation. Reasonable people could take either side of the argument.

I tend to fall on the side of environmentalists. While the regulatory burden is a concern, people and economies adjust over time, as long as burden is reasonable. If a tougher standard was enforced, I think we would see some loss of economic activity and employment. But when regulations are enforced in an intelligent way, people eventually get used to them and learn to work within them. For example, take EPA’s Acid Rain Program, legislated in 1990 as part of the Clean Air Act and put into effect in 199517. The Acid Rain Program is a cap-and-trade program, enabling industries that are able to cut their sulfur dioxide emissions beneath a certain limit to sell the rights to emit the saved sulfur dioxide to other industries. This program may have played a major role in sharply reducing emissions in the U.S.18 People seem to have adjusted to it, with very little vocal opposition that I am aware of. Nobody has blamed the Acid Rain Program for the poor state of the economy.

But the key is that stricter standards must be intelligently enforced with sensitivity to the needs of business; heavy-handed regulation blindly administered with no regards to business can really be a drag on the economy. Not being an expert, I’m not sure how to do intelligent enforcement. However, I understand that Obama’s current nominee for EPA Administrator, Gina McCarthy, is a strong believer in working with business to find the best solutions to environmental problems. If so, she’d be perfect for the job, and I strongly urge the Senate to confirm her as soon as possible.

Yet the stricter standard was scuttled. I think part of the problem is that EPA’s manner can be rather imperious and somewhat patronizing, laying down new regulations without any serious input from other stakeholders. There was a period of public comment to which the agency responded19, but my impression is that the agency merely rebutted criticism rather than try to incorporate people’s concerns into the decision process. Naturally, affected stakeholders are resentful. As it writes a new standard into law, the EPA needs to build cooperation with stakeholders, and that was what was sorely lacking in the process. Everybody’s concerns need to be addressed and it’s important they feel their needs are being addressed.

Moreover, EPA tried to enact the new standard without garnering public support first. When I first learned of Obama’s retraction, I had never heard of the new ozone rule, and I doubt many people did, either. Many people were wondering, what is this bothersome new regulation all about and why is it important? EPA can still win a stricter ozone standard, but to accomplish that it must first raise awareness about the problems of ground-level ozone among the public. It can do this by working with environmental advocacy organizations and patient advocacy organizations (such as the American Lung Association) to build public awareness of ground-level ozone and its effects. Either it or a surrogate can build a major ad campaign to push ozone to the forefront of the national consciousness (how about the slogan “Ozone Kills!”). It can devise educational presentations that schools can use in their classrooms. It can put scientists and researchers on news programs and talk shows. It can have them write articles and op-ed pieces in newspapers and popular magazines. If there is a popular demand for stricter ozone standards, there will be a much better chance that the standards will make it into law.

I’ve wondered how ozone levels affect the performance of players in major league sports, particularly those played out-of-doors (baseball and football especially). If a negative correlation could be proved, we might have major league sports as allies. Players are occasionally accused of taking performance-enhancing drug. What if it could be proved that low-ozone air is a performance-enhancing drug that is perfectly legal?

Also, we need more research into ozone. I mentioned before that very few scientific studies have looked at the effects of 40 — 60 ppb ozone on subjects in the laboratory20. It also seems that there is a dearth of laboratory studies that have had asthmatics and other COPD (chronic obstructive pulmonary disease) sufferers as subjects21. We need more of these studies. We need to publicize epidemiological studies that compare the effects of living in areas of the country with high ozone concentrations with those of lower concentrations to convince people there is a difference, and that it affects them personally.

As for the secondary standard, I’d hold off on that. If the purpose of the secondary standard was to shore up struggling ecosystems and prevent species extinction, it would be worth fighting for. But if its main purpose is to protect property, then why should we be fighting for the concerns of property owners? We ought to educate people as to what a secondary standard can accomplish, but it shouldn’t be our responsibility to try to impose it. That should be for the beneficiaries, home owners, property owners, and farmers to demand. If they lobby EPA for it or if Congress pushes for it, the EPA should consider it. But if no stakeholders think they need such a standard, then we really don’t need it and we shouldn’t be pursuing it. With a world full of environmental threats, we need to choose our battles carefully, and this is a battle not worth fighting. We need to save our time, energy, and effort for where it is more needed.

So those are my conclusions and recommendations, which you can accept or reject as you see fit. Thank you for taking the time to read this topic, and I hope you found it helpful to understand an important public health issue.


Footnotes:

  1. Statement by the President on the Ozone National Ambient Air Qualities Standards. White House website. To view, click here.
  2. See my post The EPA’s New Ozone Rule: Part 1. To view it, click here.
  3. See my post The EPA’s New Ozone Rule: Part 7. To view it, click here. See also my blog pages Ozone Excerpts 1, which you can view here, and Ozone Excerpts 2, which you can view here.
  4. For example, see the six papers listed in my post The EPA’S New Ozone Rule: Part 22, which you can view by clicking here.
  5. I admit I’m on very shaky ground here: I haven’t actually seen a scientific study on the economic effects of regulation. Perhaps I’ve bought too deeply into the arguments of conservative Republicans and the Tea Party. But it makes sense that if companies are forced to spend large amounts of money, time, and effort on government regulations, they will have less resources to spend on their business and less money to pay employees. The regulations may be necessary or even vital, but there’s always a cost. Of course, the net cost to the world economy is lessened because money spent on regulation benefits other businesses. The net cost to the U.S. economy is lessened, too, if money spent on conforming to regulations is spent on U.S. businesses.
  6. See my post The EPA’s New Ozone Rule: Part 4, which you can view by clicking here.
  7. See my posts The EPA’s New Ozone Rule: Part 6, which you can view by clicking here, and The EPA’s New Ozone Rule: Part 15, which you can view by clicking here.
  8. See my post The EPA’s New Ozone Rule: Part 7. To view it, click here. See also my blog pages Ozone Excerpts 1, which you can view here, and Ozone Excerpts 2, which you can view here. As for the damage that ozone causes property, I haven’t really discussed that in any depth. However, in Ozone Excerpts 1, see Table 1-2: Summary of ozone causal determination for welfare effects, vegetation, and ecosystem effects. In Ozone Excerpts 2, see Table 2-2: Summary of ozone causal determinations for vegetation and ecosystem effects.
  9. See my post The EPA’s New Ozone Rule: Part 8. To view it, click here.
  10. See my posts The EPA’s New Ozone Rule: Part 10 through Part 14. You can view any of these posts by clicking on the following:     Part 10,     Part 11,     Part 12,     Part 13,     Part 14.
  11. See my posts The EPA’s New Ozone Rule: Part 15 through Part 18. You can view any of these posts by clicking on the following:     Part 15,     Part 16,     Part 17,    Part 18.
  12. For Administrator Stephen Johnson’s view, see my post The EPA’s New Ozone Rule: Part 10 which you can view by clicking here. For Administrator Lisa Jackson’s view, see my posts The EPA’s New Ozone Rule: Part 11, click here to view, and The EPA’s New Ozone Rule: Part 12, click here to view.
  13. See my posts The EPA’s New Ozone Rule: Part 17. To view it, click here.
  14. See my posts The EPA’s New Ozone Rule: Part 20 and Part 21. To view Part 20, click here. To view Part 21, click here.
  15. See my post The EPA’s New Ozone Rule: Part 22. To view it, click here.
  16. See my post The EPA’s New Ozone Rule: Part 23. To view it, click here.
  17. U.S. Environmental Protection Agency website, Clean Air Markets Acid Rain Program. To view, click here.
  18. For example, U.S. Environmental Protection Agency, Acid Rain and Related Programs: 2009 Highlights, 15 Years of Results 1995 to 2009. To review the report, click here.
  19. For example, U.S. Environmental Protection Agency, National Ambient Air Quality Standards for Ozone, July 2011, Section II.C.2. “Comments on the Proposed Decision”, pp. 77 – 163.
  20. See my post The EPA’s New Ozone Rule: Part 9. To view it, click here.
  21. This observation was made from inference. The U.S. Envronmental Protection Agency’s document National Ambient Air Quality Standards for Ozone, July 2011, states (p.38) “The most certain evidence of adverse health effects from exposure to O3 comes from the controlled human exposure studies, as discussed in the 2010 proposal in section II.A.2, and the large bulk of this evidence derives from studies of exposures at levels of 0.080 ppm and above. At those levels, there is consistent evidence of lung function decrements and respiratory symptoms in healthy young adults, as well as evidence of inflammation and other medically significant airway responses.” Later on, the document mentions the Adams studies at the only controlled studies “that examine respiratory effects associated with prolonged O3 exposures at levels below 0.080 ppm.” But the Adams studies only used healthy subjects. Thus, the number of controlled studies using subjects with COPD and other respiratory ailments must be few and far between.

EPA’s New Ozone Rule: Part 18

In our last post, we saw how EPA’s CASAC reacted strongly to its decision to make the secondary standard of ground-level ozone identical to the primary standard. That influenced EPA to reconsider its decision as reported in the document National Ambient Air Quality Standards for Ozone, Final Preamble, 2011 (p. 215):

In reconsidering the 2008 final rule in the 2010 proposal, the Administrator agreed with the conclusions drawn in the 2006 Criteria Document, 2007 Staff Paper and by CASAC that the scientific evidence available in the 2008 rulemaking continues to demonstrate the cumulative nature of O3 – induced plant effects and the need to give greater weight to higher concentrations. Thus, the Administrator concluded that a cumulative exposure index that differentially weights O3 concentrations represents a reasonable policy choice for a secondary standard to protect against the effects of O3 on vegetation during the growing season. The Administrator further agreed with both the 2007 Staff Paper and CASAC that the most appropriate cumulative, concentration-weighted form to consider is the sigmoidally weighted W126 form.

As EPA noted before, the amount of protection the primary standard would give to vegetation is uncertain, but the hint is that EPA is now prepared to err on the side of regulation. In this excerpt (p. 216), EPA argues that we can’t be sure that the primary standard can protect vegetation as well as the W126 standard. A comparison is hard to make because the results of such a comparison would likely differ from year to year, and because we don’t have enough data in the areas where the secondary standard might do the most good, in rural areas. (The paragraph sign [¶] indicates a paragraph break that I introduced that wasn’t there in the original text. The “8-hour average standard” is the primary standard, which averages ozone readings taken during an eight-hour period.):

The Administrator noted that… EPA proposed a second option of revising the then-current 8-hour average secondary standard by making it identical to the proposed 8-hour primary standard. The 2007 Staff Paper analyzed the degree of overlap expected between alternative 8-hour and cumulative seasonal secondary standards using recent air quality monitoring data. Based on the results, the 2007 Staff Paper concluded that the degree to which the current 8-hour standard form and level would overlap with areas of concern for vegetation expressed in terms of the 12-hour W126 standard is inconsistent from year to year and would depend greatly on the level of the 12-hour W126 and 8-hour standards selected and the distribution of hourly O3 concentrations within the annual and/or 3-year average period.

¶ The 2007 Staff Paper also recognized that meeting the then current or alternative levels of the 8-hour average standard could result in air quality improvements that would potentially benefit vegetation in some areas, but urged caution be used in evaluating the likely vegetation impacts associated with a given level of air quality expressed in terms of the 8-hour average form in the absence of parallel W126 information. This caution was due to the concern that the analysis in the 2007 Staff Paper may not be an accurate reflection of the true situation in non-monitored, rural counties due to the lack of more complete monitor coverage in many rural areas. Further, of the counties that did not show overlap between the two standard forms, most were located in rural/remote high elevation areas which have O3 air quality patterns that are typically different from those associated with urban and near urban sites at lower elevations. Because the majority of such areas are currently not monitored, there are likely to be additional areas that have similar air quality distributions that would lead to the same disconnect between forms. Thus, the 2007 Staff Paper concluded that it remains problematic to determine the appropriate level of protection for vegetation using an 8-hour average form. [emphasis mine — MHK]

Now here is the real rationale behind the secondary rule: cumulative exposure hurts plants more than it hurts humans. But why that should be? That question I can’t answer. The document continues (p. 217):

The Administrator also noted in the 2010 proposal that CASAC recognized that an important difference between the effects of acute exposures to O3 on human health and the effects of O3 exposures on welfare [of vegetation — MHK] is that vegetation effects are more dependent on the cumulative exposure to, and uptake of, O3 over the course of the entire growing season (Henderson, 2006c). The CASAC O3 Panel members were unanimous in concluding the protection of natural terrestrial ecosystems and managed agricultural crops requires a secondary O3 standard that is substantially different from the primary O3 standard in form, averaging time, and level (Henderson, 2007).

That concludes the EPA’s rationale in the document. Again, it seems to me that the decision was based on a judgement call. You may agree with me that there is less of a moral imperative to safeguard property and crops than there is safeguarding human life, so when evaluating the secondary standard, it makes even more sense to compare gains and losses. True, a secondary standard might improve agricultural crops, but is it worth the additional cost to industry to maintain that standard? That question is especially hard to answer when we don’t know exactly how much benefit the secondary standard would bring us above and beyond the primary standard. It’s a very tricky question. More about this in my final comments on the subject. In the meantime, let’s discuss how EPA standards are implemented.

EPA’s New Ozone Rule: Part 17

In our previous post, the EPA explained why it found a secondary standard necessary to protect vegetation Indeed, when EPA’s Clean Air Scientific Advisory Committee (CASAC) found out, they strongly objected. I can imagine that a journalist reporting on CASAC would use words like “furious”, “enraged”, “livid.” They let the EPA know in no uncertain terms how they felt as reported in the document National Ambient Air Quality Standards for Ozone, Final Preamble, 2011 (p. 212):

Following the 2008 decision on the O3 standards, serious questions were raised as to whether the standards met the requirements of the CAA [Clean Air Act — MHK]. In April 2008, the members of the CASAC Ozone Review Panel sent a letter to EPA stating “[i]n our most-recent letters to you on this subject – dated October 2006 and March 2007 – … the Committee recommended an alternative secondary standard of cumulative form that is substantially different from the primary Ozone NAAQS in averaging time, level and form — specifically, the W126 index within the range of 7 to 15 ppm-hours, accumulated over at least the 12 “daylight” hours and the three maximum ozone months of the summer growing season” (Henderson, 2008). The letter continued: “[t]he CASAC now wishes to convey, by means of this letter, its additional, unsolicited advice with regard to the primary and secondary Ozone NAAQS. In doing so, the participating members of the CASAC Ozone Review Panel are unanimous in strongly urging you or your successor as EPA Administrator to ensure that these recommendations be considered during the next review cycle for the Ozone NAAQS that will begin next year” (id.).

Now CASAC is going to really lay into the EPA!

The letter further stated the following views:

The CASAC was … greatly disappointed that you failed to change the form of the secondary standard to make it different from the primary standard. As stated in the preamble to the Final Rule, even in the previous 1996 ozone review, ‘there was general agreement between the EPA staff, CASAC, and the Administrator, … that a cumulative, seasonal form was more biologically relevant than the previous 1-hour and new 8-hour average forms (61 FR 65716)’ for the secondary standard. Therefore, in both the previous review and in this review, the Agency staff and its advisors agreed that a change in the form of the secondary standard was scientifically well-justified.

Unfortunately, this scientifically-sound approach of using a cumulative exposure index for welfare effects was not adopted, and the default position of using the primary standard for the secondary standard was once again instituted. Keeping the same form for the secondary Ozone NAAQS as for the primary standard is not supported by current scientific knowledge indicating that different indicator variables are needed to protect vegetation compared to public health. The CASAC was further disappointed that a secondary standard of the W126 form was not considered from within the Committee’s previously-recommended range of 7 to 15 ppm-hours. The CASAC sincerely hopes that, in the next round of Ozone NAAQS review, the Agency will be able to support and establish a reasonable and scientifically-defensible cumulative form for the secondary standard.” (Henderson, 2008)

Wow! You can almost feel the burning red-hot indignation behind this rhetoric which I suspect was toned down quite a bit. In our next post, we’ll see how the EPA reacted.

EPA’s New Ozone Rule: Part 16

We are continuing our discussion in our last post about why the EPA felt it necessary to formulate a new secondary standard for ground-level ozone concentration. As we noted before, initially the EPA felt it adequate for the secondary standard to be identical to the primary standard, but then it reconsidered its position.

The EPA performed an evaluation comparing primary and secondary standards and found that high cumulative exposures were widespread. Below is a summary of what they found, taken from the document National Ambient Air Quality Standards for Ozone, Final Preamble, 2011. Note point #4 where EPA explains why it thinks the primary standard is insufficient (p. 201):

…The following key observations were drawn from comparing predicted changes in interpolated air quality under each alternative standard form and level scenario analyzed:

  1. The results of the exposure assessment indicate that then-current air quality levels could result in significant impacts to vegetation in some areas. For example, [bulleted list is my formatting — MHK]
    • For the base year (2001), a large portion of California had 12-hr W126 O3 levels above 31 ppm-hours, which has been associated with approximately up to 14% biomass loss in 50% of tree seedling cases studies.
    • Broader multi-state regions in the East (NC, TN, KY, IN, OH, PA, NJ, NY, DE, MD, VA) and West (CA, NV, AZ, OK, TX) are predicted to have levels of air quality above the W126 level of 21 ppm-hours, which is approximately equal to the secondary standard proposed in 1996 and is associated with biomass loss levels no greater than approximately 9% in 50% of tree seedling cases studied, and biomass loss levels greater than approximately 9% in the other 50%.
    • Much of the East and Arizona and California have 12- hour W126 O3 levels above 13 ppm-hours which has been associated with biomass loss levels no greater than approximately 7% biomass loss in 75% of tree seedling cases studied and biomass loss levels greater than approximately 7% in the remaining 25% of cases studied.
  2. When 2001 air quality was rolled back to meet the then current 8-hour secondary standard, the overall 3-month 12-hour W126 O3 levels were somewhat improved, but not substantially. Under this scenario, there were still many areas in California with 12-hour W126 O3 levels above 31 ppm hours. A broad multi-state region in the East (NC, TN, KY, IN, OH, PA, MD) and West (CA, NV, AZ, OK, TX) were still predicted to have O3 levels above the W126 level of 21 ppm-hours.
  3. Exposures generated for just meeting a 0.070 ppm, 4th-highest maximum 8-hour average alternative standard (the lower end of the proposed range for the primary O3 standard) showed substantially improved O3 air quality when compared to just meeting the then-current 0.08 ppm, 8-hour standard. Most areas were predicted to have O3 levels below the W126 level of 21 ppm-hr, although some areas in the East (KY, TN, MI, AR, MO, IL) and West (CA, NV, AZ, UT, NM, CO, OK, TX) were still predicted to have O3 levels above the W126 level of 13 ppm-hours.
  4. While these results suggested that meeting a proposed 0.070 ppm, 8-hour secondary standard would provide substantially improved protection in some areas, the Staff Paper recognized that other areas could continue to have elevated seasonal exposures, including forested park lands and other natural areas, and Class I areas which are federally mandated to preserve certain air quality related values. This is especially important in the high elevation forests in the western U.S. where there are few O3 monitors and where air quality patterns can result in relatively low 8-hour averages while still experiencing relatively high cumulative exposures.

Now the EPA will explain where in particular the lack of a separate secondary standard is a problem. It seems that ozone levels in high-elevation rural areas remain fairly constant during the day, so that the ozone concentration may be below the primary standard and yet deliver a large cumulative exposure. This is where attention to a cumulative-based secondary standard might be particularly useful. Note that the 8-hour average form refers to the primary standard, which depends on the average of ozone measurements taken during an eight-hour time period (p. 202):

To further characterize O3 air quality in terms of the 8-hour and alternative secondary standard forms, an analysis was performed in the 2007 Staff Paper to evaluate the extent to which county-level O3 air quality measured in terms of various levels of the 8-hour average form overlapped with that measured in terms of various levels of the 12-hour W126 cumulative, seasonal form. This analysis was limited by the lack of monitoring in rural areas where important vegetation and ecosystems are located, especially at higher elevation sites. This is because O3 air quality distributions at high elevation sites often do not reflect the typical urban and near-urban pattern of low morning and evening O3 concentrations with a high mid-day peak, but instead maintain relatively flat patterns with many concentrations in the mid-range (e.g., 0.05-0.09 ppm) for extended periods. These conditions can lead to relatively low daily maximum 8-hour averages concurrently with high cumulative values so that there is potentially less overlap between an 8-hour average and a cumulative, seasonal form at these sites. The 2007 Staff Paper concluded that it is reasonable to anticipate that additional unmonitored rural high elevation areas important for vegetation may not be adequately protected even with a lower level of the 8-hour form.

Then the EPA seems to reverse its position. Since we can’t be confident that the primary standard will be adequate, especially in rural areas and remote areas where data on ozone might be sparse, we may need to establish a secondary standard. Whereas before the EPA wanted to err on the side of less regulation, now they want to err on the side of more regulation (p. 203):

It continues to remain uncertain as to the extent to which air quality improvements designed to reduce 8-hour O3 average concentrations would reduce O3 exposures measured by a seasonal, cumulative W126 index. The 2007 Staff Paper indicated this to be an important consideration because:

  1. The biological database stresses the importance of cumulative, seasonal exposures in determining plant response;
  2. Plants have not been specifically tested for the importance of daily maximum 8-hour O3 concentrations in relation to plant response;
  3. The effects of attainment of a 8-hour standard in upwind urban areas on rural air quality distributions cannot be characterized with confidence due to the lack of monitoring data in rural and remote areas.

These factors remain important considerations in the Administrator’s reconsideration of whether the current 8-hour form can appropriately provide requisite protection for vegetation.

Question on point #3: If we can’t be sure of the effects of attainment of an 8-hour standard on rural areas because we don’t have enough monitoring data, how would we be any more sure of the effects of attainment of the secondary standard?

The EPA’s own CASAC (Clean Air Scientific Advisory Committee) was also very unhappy with the decision to make the secondary standard equal to the primary standard. We will see what they have to say in the next post.

EPA’ s New Ozone Rule: Part 15

A major innovation of EPA’s 2010 revision of the ozone standard was the introduction of what is called a secondary standard that is different from the primary standard. The secondary standard has existed before, but it was always set identical to the primary standard. To summarize the two standards:

  • The primary standard is intended to protect the public health. It is currently based on the fourth-highest 8-hour average ozone concentration reading in a year.
  • The secondary standard is meant to protect property, economic interests, and other concerns. It is based on a cumulative ozone concentration over time. Ozone readings are taken hourly between 8 a.m. and 7 p.m., adjusted by what is called the W126 rule, and then summed during a three-month period. Units are in ppm-hours. See what I wrote in this blog about the secondary standard in the post “EPA’s New Ozone Rule: Part 6.” To view, click here.

Now if one standard was consistently stricter than the other, the EPA could simply adopt the stricter standard. That it felt necessary to formulate two standards can only mean that in some places one standard will be harder to meet, and in other places the other standard will be the stricter. The EPA wants to meet both standards everywhere, a condition we Orthodox Jews call being machmir for both shitos.

What I don’t understand yet is why the primary standard, which is meant to safeguard public health, is based on a highest one-time average, whereas the secondary standard, meant to protect property, is based on a cumulative measure. A cumulative standard makes sense, because research shows that the extent of damage to plants caused by ozone depends on cumulative exposure. But perhaps damage to human health also depends on cumulative exposure, just as the damage caused by radiation to human health depends on cumulative exposure. Why not make the primary standard cumulative as well? Be that as it may, currently the primary standard remains based on a highest one-time average, while the secondary standard remains identical to the primary standard.

What I want to do in this post is quote EPA in its own words why it felt a new secondary standard was necessary, discussed in the document National Ambient Air Quality Standards for Ozone, Final Preamble, 2011.

From the outset, the EPA is clear that the secondary standard was formulated because of ozone’s effects on plants (p. 196):

…The 2006 Criteria Document concluded that O3 exposure indices that cumulate differentially weighted hourly concentrations are the best candidates for relating exposure to plant growth responses…

It is interesting that the EPA recognized the value of a secondary standard long before 2010 (p. 197):

At the conclusion of the 1997 review, the biological basis for a cumulative, seasonal form was not in dispute. There was general agreement between the EPA staff, CASAC, and the Administrator, based on their review of the air quality criteria, that a cumulative, seasonal form was more biologically relevant than the previous 1-hour and new 8-hour average forms (61 FR 65716).

The EPA also explained why, rather than summing up straight ozone concentrations, it chose to sum up modified values, referred to as the W126 form. Using W126 values gives more weight to higher concentrations and much less weight to lower concentrations that would exist either naturally without human activity, or from foreign sources beyond the control of the U.S. government (p. 198):

Regarding the first consideration, the 2007 Staff Paper noted that the W126 form, by its incorporation of a continuous sigmoidal weighting scheme, does not create an artificially imposed concentration threshold, yet also gives proportionally more weight to the higher and typically more biologically potent concentrations, as supported by the scientific evidence. Second, the index value is not significantly influenced by O3 concentrations within the range of estimated PRB [policy-relevant background, the level of ozone not caused by human activity in the U.S. — MHK], as the weights assigned to concentrations in this range are very small.

Nevertheless, the EPA retained a secondary standard identical to the primary standard until 2010. Initially, the EPA felt that if the primary standard was made more strict, it would be sufficient for the secondary standard were made identical to it. A separate secondary standard that was cumulative would provide no additional protection unless it was made very strict, which can’t be justified because our knowledge of the effects of low-level ozone on vegetation is so uncertain (the paragraph sign [¶] indicates a paragraph break that I inserted. P. 209):

In considering the appropriateness of establishing a new standard defined in terms of a cumulative, seasonal form, or revising the 1997 secondary standard by making it identical to the revised primary standard, … EPA first considered the 2007 Staff Paper analysis of the projected degree of overlap between counties with air quality expected to meet the revised 8-hour primary standard, set at a level of 0.075 ppm, and alternative levels of a W126 standard based on currently monitored air quality data. This analysis showed significant overlap between the revised 8-hour primary standard and selected levels of the W126 standard form being considered, with the degree of overlap between these alternative standards depending greatly on the W126 level selected and the distribution of hourly O3 concentrations within the annual and/or 3-year average period. On this basis, as an initial matter, EPA concluded that a secondary standard set identical to the proposed primary standard would provide a significant degree of additional protection for vegetation as compared to that provided by the then-current 0.084 ppm secondary standard.

¶ In further considering the significant uncertainties that remain in the available body of evidence of O3-related vegetation effects and in the exposure and risk analyses conducted for the 2008 rulemaking, and the difficulty in determining at what point various types of vegetation effects become adverse for sensitive vegetation and ecosystems, EPA focused its consideration on a level for an alternative W126 standard at the upper end of the proposed range (i.e., 21 ppm-hours). The 2007 Staff Paper analysis showed that at that W126 standard level, there would be essentially no counties with air quality that would be expected both to exceed such an alternative W126 standard and to meet the revised 8-hour primary standard – that is, based on this analysis of currently monitored counties, a W126 standard would be unlikely to provide additional protection in any monitored areas beyond that likely to be provided by the revised primary standard.

The EPA states again that with the lack of extensive monitoring in rural areas, it is unsure how much additional protection a separate secondary standard would provide. At this point, it decided to err on the side of less regulation. Note that the term “8 hour standard” refers to the primary standard, which averages readings over eight-hour periods (p. 210):

The EPA also recognized that the general lack of rural monitoring data made uncertain the degree to which the revised 8-hour standard or an alternative W126 standard would be protective in those areas, and that there would be the potential for not providing the appropriate degree of protection for vegetation in areas with air quality distributions that result in a high cumulative, seasonal exposure but do not result in high 8-hour average exposures. While this potential for under-protection using an 8- hour standard was clear, the number and size of areas at issue and the degree of risk was hard to determine. However, EPA concluded at that time that an 8-hour standard would also tend to avoid the potential for providing more protection than is necessary, a risk that EPA concluded would arise from moving to a new form for the secondary standard despite significant uncertainty in determining the degree of risk for any exposure level and the appropriate level of protection, as well as uncertainty in predicting exposure and risk patterns.

…EPA concluded at that time that establishing a new secondary standard with a cumulative, seasonal form would result in uncertain benefits beyond those afforded by the revised primary standard and therefore may be more than necessary to provide the requisite degree of protection.

Eventually, though, the EPA changed its mind. Why will be discussed in the next post.

EPA’s New Ozone Rule: Part 8

In 2008, the EPA under George W. Bush reduced the maximum allowable concentration of ground-level ozone from 80 ppb to 75 ppb1. Two years later, the EPA decided to reduce the limit still further to 70 ppb.2. What made the EPA decide to do so in only two years? This was unusual because the Clean Air Act only requires the EPA to review its policy on ozone once every five years, the next review required in 20133. What was the rush?

In April 2008, soon after the EPA lowered the standard, the Clean Air Scientific Advisory Committee (CASAC, EPA’s scientific advisory board on clean air4) sent the EPA a letter strongly disagreeing with the new standard, claiming that the new ozone standard was not low enough to provide a margin of safety. It wanted a primary standard between 60 and 70 ppb. In addition, CASAC felt that a different secondary standard should be established to protect property and the environment. This standard should be cumulative rather than be based on highest average readings5.

A month later, a number of groups challenged EPA’s standards in court. Some of them felt the standard went too far: business interests and some states. Other petitioners felt the standard did not go far enough: environmental organizations, public health organizations, and other states. These lawsuits were consolidated into one: State of Mississippi et al v. U.S. Environmental Protection Agency. In March 2009, the EPA filed an unopposed motion to hold the lawsuit in abeyance while it reviewed the new standard. 6 The revised standard, which lowered the maximum allowable concentration from 75 ppb to 70 pbb, was published in July 20117. In September 2011, the Obama administration requested that the EPA rescind its new standard8.

The document which lays out this new standard, National Ambient Air Quality Standards for Ozone, Final Preamble published July 7, 2011, lays out a detailed explanation of EPA thinking: why it didn’t think 75 ppb was a good enough standard, why 60 ppb was too low and 70 ppb was about right, and why it felt a new secondary standard to protect property and the environment was necessary9. I am going to try to summarize that thinking here.

Footnotes:

  1. U.S. Environmental Protection Agency, Integrated Science Assessment for Ozone and Related Photochemical Oxidants, Third External Review Draft, June 2012, p.lxxiii.
  2. U.S. Environmental Protection Agency, National Ambient Air Quality Standards for Ozone, Final Preamble, 2011, p.6.
  3. United States Code, Title 42, Chapter 85, §7409 (d)(1). To view, click here.
  4. The Clean Air Act requires that an independent scientific body review the NAAQS at five-year intervals and make recommendations. CASAC currently fulfils this role. See United States Code, Title 42, Chapter 85, §7409 (d)(2). To view, click here.
  5. U.S. Environmental Protection Agency, National Ambient Air Quality Standards for Ozone, Final Preamble, 2011, p.18.
  6. ibid.pp.29-30
  7. This is the National Ambient Air Quality Standards for Ozone, Final Preamble, 2011 that has been referred to above.
  8. Statement by the President on the Ozone National Ambient Air Qualities Standards. White House website. To view, click here.
  9. U.S. Environmental Protection Agency, National Ambient Air Quality Standards for Ozone, Final Preamble, 2011. The rationale for the primary standard (section II) starts on p. 34 and the rationale for the secondary standard (section III) starts on p. 192.

EPA’s New Ozone Rule: Part 6

Let’s look at EPA’s proposed ozone rule to see exactly what it entails. Unlike previous ozone rules, it has two distinct parts1:

  • A primary standard to protect human life and health.
  • A secondary standard to protect property, agriculture, and the environment.

Technically speaking, EPA rules always had primary and secondary standards, but up to now, the ozone primary and secondary standards were identical2. This is the first time that the two standards were made distinct, done at the urging of EPA’s Clean Air Scientific Advisory Committee (CASAC)3.

The two standards are different in character. The primary standard is based solely on averages4. If the average ozone concentration rises above a certain level, that location is in non-attainment. The secondary standard is based on cumulative exposure to ozone1. It is more focused on the effects caused by long-term exposure to ozone.

The new rule is making an interesting statement: it appears that with regards to human health we are more interested in the acute effects of high exposure. With property and agriculture, we seem more concerned with ozone’s long term effects. Yet the EPA is aware of that long-term exposure to ozone can degrade human health over time.

Now if a locale is to be in attainment, it presumably must meet both the primary and secondary standards. Sometimes one standard will be more stringent, sometimes the other. Consider locales which meet one standard and not the other. In one locale, ozone levels are usually very low. Occasionally, they peek to high levels, just often enough so that the locale does not meet the primary standard, yet the cumulative exposure to ozone remains low. In another locale, ozone levels are consistently high causing large cumulative exposure, but they fall just shy of breaking the primary standard. State and Federal authorities will need to keep track on two sets of numbers for each locale to enforce both standards.

The primary standard in the proposed rule is actually the same as in current rule, just a little stricter, the maximum concentration lowered from 75 ppb in the current rule to 70 ppb. The air is sampled frequently at a measuring station, and readings are averaged out over an eight-hour period. This yields 1,095 such averages in a calendar year (1,098 in a leap year). The three highest averages are thrown out and the fourth-highest average is used to represent the year’s maximum. The maximums from three consecutive years are then averaged together. If this composite average exceeds 70 ppb, that locale is considered in nonattainment1.

The secondary standard is a little more complicated but easily understandable if you remember your high school algebra. The values to be summed are not the ozone concentrations themselves but a calculation based on each reading of ozone concentration, called the W126 index5. To determine, the cumulative index, hourly readings of ozone concentrations are taken at an individual station 12 hours a day, starting at 8 a.m. and finishing at 7 p.m. A value Wi is then calculated as follows:

                                     Wi =        Ci                 
1 + 4403e –ACi

where:

Ci (read as “C sub i”) is the reading of ozone concentration measured in parts per million (ppm) taken at hour i. Because the W126 index is cumulative, Ci is in units of ppm-hours.

e is the base of natural logarithms, approximately equal to 2.71828.
A is a constant equal to 126/ppm-hour.

For example, suppose at 2:00 in the afternoon we measured an ozone concentration of .083 ppm. We would then calculate a W value for 2 pm this way:

             W2pm =                              .083 ppm-hours                   
                                1 + (4403)(e – (126/ppm-hour)(.083 ppm-hours))

This can easily be calculated with the help of a scientific calculator6 (note that the ppm-hours units cancel in the exponent as they should), yielding a value of 0.74 ppm-hours. This means that the ozone concentration at 2 pm will contribute slightly less to the cumulative total than if we did not use the formula (.074 ppm-hours versus .083 ppm-hours).

The Wi values are summed each day, giving a daily cumulative total:

Wdaily = ΣWi

summed from the first reading of the day at 8 am to the last reading at 7 pm.

The Wdaily values are themselves summed over a three-month period. As I understand it, these are running totals: January-February-March, February-March-April, March-April-May, and so on.

W126 = ΣWdaily

summed from the first day of each three-month period through the last day.

Thus, each calendar year produces ten W126 values, from January-February-March through October-November-December. The highest W126 value for the year is selected. This process is carried out for three consecutive years, producing three yearly maximum W126 values. The average of these three values is the final W126 value. If it is higher than 13 ppm-hours, then the area where the readings were taken is declared to be in non-attainment5.

For example, the following are fictitious highest W126 totals summed up during each of 2008, 2009, and 2010. All values are in ppm-hours:

Year Highest Value Period Summed
2008 15.2 Apr-May-Jun
2009 14.3 May-Jun-Jul
2010 12.9 Mar-Apr-May

The average of these three values is 14.1 ppm-hours. Since this is above the standard of 13 ppm-hours, the area from where these readings were taken is in non-attainment.

Why is the W126 index used? To quote A.S.L. & Associates, a Montana company whose founder developed the W126 index:

The W126 index is a cumulative exposure index that is biologically based. The W126 ozone index focuses on the higher hourly average concentrations, while retaining the mid- and lower-level values. By applying a continuous weighting, the W126 index has the advantage of not utilizing an artificial “threshold.”

In 1985, A.S. Lefohn proposed the use of the W126 ozone exposure index for predicting vegetation effects. The cumulative W126 exposure index uses a sigmoidally weighted function (i.e., “S” shaped curve) as described by Lefohn and Runeckles (1987) and Lefohn et al. (1988). The W126 index is a cumulative exposure index and not an “average” value. It is a biologically based index, which is supported by research results (i.e., under both experimental and ambient conditions) that show that the higher hourly average ozone concentrations should be weighted greater than the mid- and lower-level values. The W126 index is accumulated over a specified time period.7

Let’s look again at the equation that defined the individual hourly W126 values, designated as Wi:

                                     Wi =        Ci                 
1 + 4403e –ACi

Let’s plot the Wi values on a graph as a function of the original hourly ozone concentrations that generated them, Ci:

Graph of Wi values plotted against the ozone concentrations used to calculate the values.

As the graph shows, when the ozone concentration Ci is less than .035 ppm-hour, Wi values are negligible. As Ci increases, the Wi values quickly climb, but are still always less than Ci. As Ci increases beyond about .085 ppm-hour, the growth rate of Wi subsides somewhat until about .10 ppm-hour, when Ci nearly equals Wi (within 1%), and the graph becomes linear. This shows that for ozone concentrations less than 0.035 ppm, the W126 values contribute almost nothing to the cumulative total. For concentrations greater than than .100 ppm, the W126 values are almost identical to the ozone concentrations. In between 0.035 ppm and .100 ppm, the contribution varies, with larger concentrations contributing much more to the cumulative total than smaller concentrations.

You can also see this in a table that I prepared of oxygen concentrations in increments of .010 ppm and their corresponding W126 values:

Ozone   Percent of Ozone
Concentration (ppm) W126 Value Concentration
0.01 0.0000 0.08%
0.02 0.0001 0.28%
0.03 0.0003 0.99%
0.04 0.0014 3.39%
0.05 0.0055 11.01%
0.06 0.0182 30.36%
0.07 0.0424 60.59%
0.08 0.0675 84.42%
0.09 0.0855 95.03%
0.10 0.0985 98.54%

Footnotes:

  1. U.S. Environmental Protection Agency, National Ambient Air Quality Standards, 2010, pg. 1 and pg. 6
  2. U.S. Environmental Protection Agency website, Ozone (O3) Standards – Table of Historical Ozone NAAQS. To view, click here.
  3. U.S. Environmental Protection Agency, National Ambient Air Quality Standards, 2010, pg. 17.
  4. ibid., pg. 34
  5. ibid., pg. 193.
  6. It is even easier using Microsoft Excel® or similar spreadsheet program. If an ozone concentration in ppm is in cell A1, then this formula typed in cell B1 will give the corresponding W126 value:

    = A1 / (1 + 4403 * EXP(-126*A1))

  7. A.S.L. & Associates website, How the W126 Ozone Exposure Index Was Developed. To view, click here.

EPA’ s New Ozone Rule: Part 5

On September 2, 2011, the Obama administration rescinded an EPA proposal to tighten standards on ozone in the atmosphere at ground level1.   This proposal would have:

  • Lowered the maximum allowable concentration of ground-level ozone from 75 parts per billion (ppb) to 70 ppb2. This is the primary standard whose purpose is to safeguard human health.
  • Introduced a secondary standard based on a cumulative total of ozone exposure, 13 parts per million-hours (ppm-hour) in a three month period2. One ppm-hour is the exposure one receives from breathing an atmosphere of 1 ppm ozone for one hour. Two ppm-hours is the exposure of 1 ppm for 2 hours or 2 ppm for 1 hour. The purpose of the secondary standard is to protect property, quality of life, and wildlife habitat.

The question we want to consider is: Did it serve the public interest to rescind the proposed regulation or would it have been better to allow the regulation to become law? Does the benefit that the regulation provides the public outweigh the costs or vice versa?

Some might argue that a regulation that is shown to save lives offers a benefit that outweighs all costs, but that isn’t necessarily true. We put a finite price on human life all the time: insurance companies, the courts, the medical profession, governments. To show why we must do this, ask yourself this question: suppose a single person was in grave danger but could be rescued for a billion dollars. Should the government pay a billion dollars to rescue that individual? There is a raging debate how about much money to spend on medical care for the poor at a cost much less than a billion dollars per life. There are limits to how much we can spend to rescue people, especially when the costs can affect the business and economic climate3.

Another example: suppose we want to institute environmental regulation X. X will save the lives of 1000 people but will cause 10,000 people to be laid off from their jobs. Is it worth it? What if it will save the lives of 5,000 people? 10,000 people? 100,000 people? What if X will reduce tax revenues needed for schools, sanitation, police and fire services? When the question is phrased as a matter of extremes (X will save a million lives at an economic cost of ten million dollars, or X will save a handful of lives but will wreak economic havoc), most of us would find the question easy to answer. But when the costs and benefits are more balanced, that’s when it becomes tricky.

Of course, saving lives are not the only benefits of environmental regulations4. Tougher ozone standards promise to reduce the amount and severity of respiratory illness5, even to increase general wellness, helping to keep our lung function from deteriorating over long periods of time. The atheletes among us will be able to retain their abilities longer, but even ordinary people may be able to retain their vigor longer into their old age.

Lower ozone levels could particularly benefit those with pre-existing respiratory conditions, such as asthma, chronic bronchitis, and emphysema5. While people with these conditions represent just a fraction of the population, they still deserve our consideration. We have a legislative precedent: the Americans with Disabilities Act (ADA) has made life easier for millions of people6. If we demand accommodations for the blind, the deaf, and wheelchair-bound, we should also make accommodation for those with breathing difficulties.

There are also economic benefits from tougher ozone standards. If even low concentrations of ozone make some people ill, then maintaining lower concentrations will mean less illness. That means lower health care costs, less productivity lost at work, less absences at school. Ozone also damages plant life7; lower ozone levels will benefit agriculture as well as protect other forms of property (ozone is murder on certain types of rubber8). Less tangible is the damage that can be prevented to our national parks and other wildlife habitat.

On the other hands, there could be substantial costs. Ozone is not emitted directly by industry but is formed from other chemicals released into the air9. To reduce ozone, industry (as well as private cars and trucks) must curtail these emissions, and that can be expensive. If the costs are too great, companies will become less profitable, will need to cut back on hiring, will yield less tax revenue, may be tempted to move to other jurisdictions with less onerous regulation. The EPA is prohibited by law from allowing cost considerations to influence its decision to impose new and stricter regulations10. But we are not so prohibited, and we need to weigh costs against benefits to determine how society’s interests are best served.


Footnotes:

  1. Statement by the President on the Ozone National Ambient Air Qualities Standards. White House website. To view, click here.
  2. U.S. Environmental Protection Agency, National Ambient Air Quality Standards, 2010, p. 1. To view the document, click here.
  3. A related concept is the value of statistical life (VSL), which is a measure of how much people are willing to pay for reduction of danger to life. For a discussion on determining VSL in three provinces in China, see the paper The Value of Statistical Life by Jie He and Hua Wong, World Bank eLibrary, which you can view by clicking here. See also the Wikipedia article Value of Life which you can view by clicking here.
  4. For discussions of mortality associated with ozone exposure, see the U.S. Environmental Protection Agency, Integrated Science Assessment for Ozone and Related Photochemical Oxidants, Second External Draft, September 2011, Sections 2.6.2, 6.6, 7.4.10, and 7.7. To view the document, click here, then click the button “Get the Report.”
  5. For discussions of health conditions associated with ozone exposure, see the U.S. Environmental Protection Agency, Integrated Science Assessment for Ozone and Related Photochemical Oxidants, Second External Draft, September 2011, Sections 2.6, 6.2 through 6.5, and 7.3 through 7.6. To view the document, click here, then click the button “Get the Report.”
  6. For discussions of the effect of ozone on lung health, see the U.S. Environmental Protection Agency, Integrated Science Assessment for Ozone and Related Photochemical Oxidants, Second External Draft, September 2011, Sections 6.2 and 7.2. To view the document, click here, then click the button “Get the Report.”
  7. The U.S. Equal Employment Opportunity Commission maintains a website with a good summary of the ADA, which you can view by clicking here.
  8. For discussions of the effect of ozone on vegetation and the environment, see the U.S. Environmental Protection Agency, Integrated Science Assessment for Ozone and Related Photochemical Oxidants, Second External Draft, September 2011, Sections 2.7 and 9. To view the document, click here, then click the button “Get the Report.”
  9. See my post “EPA’s New Ozone Rule, Part 4” which you can view by clicking here.
  10. U.S. Environmental Protection Agency, National Ambient Air Quality Standards, 2010, p. 9. To view the document, click here.

    Actually, this prohibition is not actually stated by the Clean Air Act, but has been inferred by the courts. It is based on Section 109 of the Clean Air Act (United States Code, Title 42, Section 7409, which you can read by clicking here) which states in subsection (b)(1): “National primary ambient air quality standards…based on such criteria and allowing an adequte margin of safety, are requisite to protect the public health.” Similarly, it states in subsection (b)(2): Any national secondary ambient air quality standard…is requisite to protect the public welfare from any known or anticipated adverse effects associated with the presence of such air pollutant in the ambient air.” The Supreme Court in its ruling in the case Whitman v. American Trucking Associations, Inc. (which you can read by clicking here) inferred from the lack of mention of cost as a criteria in determining NAAQS that cost was excluded. This is because in other places, the Clean Air Act explicitly does allow cost as a criteria. As an Orthodox Jew, I take great pleasure from this argument — it could have come straight from the Talmud.