TCS Daily


Where's EPA's Waldo?

By Kay H. Jones - August 30, 2004 12:00 AM

Waldo is the well-recognized cartoon character who hides in a highly detailed cartoon drawing, challenging the reader to find him. Only his black dot eyes wire rimmed glasses and striped stocking cap can be found after carefully scanning the drawing. Waldo is not easy to find. Neither is the identity of the subset of the Nation's population which EPA claims is currently exposed to unhealthy levels of particulate air pollution known as PM 2.5. So for discussion purposes, let's just call this segment of the population "Waldo".

The annual National Ambient Air Quality Standard (NAAQS) for PM 2.5 is 15 micrograms per cubic meter (ug/m3) and by meeting this standard only those persons exposed to levels above 15 ug/m3 are at risk. Arguments about whether or not such a health effects threshold exists has been intensely debated elsewhere but the setting of the NAAQS at 15ug/m3 in accordance with the tenets of the Federal Clear Air Act carries the inherent assumption that any health effects that might occur below 15ug/m3 are not significant or highly uncertain. To argue otherwise makes the NAAQS setting process meaningless.

So where is Waldo? EPA Administrator Leavett, in his written testimony before the Senate Subcommittee on Clean Air, Climate and Nuclear Safety (4/1/04) stated that there were 65 million people living in non attainment counties based on actual monitoring data measured over the three year period (2000, 2001, and 2002). EPA's data base shows that the number of counties showing such measured non attainment is 120. A handful of counties didn't have complete data so their attainment status could not be established. The tabulated population in the 120 listed counties is actually 58.7 million. Close enough, we think we found Waldo.

But wait he's hiding again. On June 29, 2004 EPA announced that after consulting with the States and Tribes, they have now identified 99 million persons in 244 counties who are living in non-attainment areas. How did Waldo's image get so big so quickly? Wordsmithing. The non-attainment designations are based on identifying counties who have measured PM 2.5 levels above 15ug/m3, as well as those counties who could contribute emissions to those counties who are actually in non-attainment based on actual measured data. Waldo is now wearing a fur coat to the tune of 41 million non exposed persons. No disclaimer about this huge discrepancy appears anywhere in the recent EPA pronouncements.

Is Waldo's image the same across the Nation's landscape? Not by a mile. Of the 57.7 million persons residing in the identified 120 non-attainment counties in the U.S., 21.8 million live in only 13 counties in California. Additionally, there is a very large difference in the shape and color of Waldo in California versus the rest of the Nation.

Outside of California, 86 of the 107 counties with annual concentration levels called design values above 15 ug/m3 are within the range of 15-17 ug/m3. Only one county, Allegheny, in PA has a design value above 20ug/m3. Alternatively, 10 counties in California exceed 17 ug/m3, 7 of which exceed 20 ug/m3 with a maximum exposure level of 28.9 ug/m3 in Riverside County.

Waldo's image becomes even more vivid if we estimate the relative risk of PM 2.5 exposure in California versus the rest of the Nation. The risk projections made by EPA in terms of the number of deaths, hospital visits, asthma attacks, work day losses etc. are highly questionable and based on some extreme if not false assumptions. However, EPA relies on a simple formula that multiplies population (P) times an incremental change in PM 2.5 (C) times a health damage factor (F). For example the number of excess deaths per 1 ug/m3 change in PM 2.5 exposure for all folks over age 30 is based on the most cited American Cancer Society Study by Pope et al. We can therefore compare the relative shades of Waldo in California to the rest of the Nation by simply summing the product of each non attainment county's population times the difference between that county's design value and 15 ug/m3. When the accounting is done we find that 64% of the exposure risk occurs in California regardless of the health effect one might espouse.

A further insight into the possible shades of Waldo is to look at the risk factors for persons who are exposed to PM 2.5 at levels above 18.7 ug/m3. This average level is mathematically equal to a median level of 15ug/m3. EPA did not read the original Pope paper with any degree of care because his city by city population exposure data were annual medians of PM 2.5 not means. EPA in its 1996 PM 2.5 staff paper assigned a 15 ug/m3 threshold to Pope's graphed city by city mortality versus exposure data. Hence, when they reported this 15ug/m3 threshold as the mean to support their NAAQS proposal, they actually but inadvertently set the threshold at an annual mean of 18.7ug/m3. EPA has never corrected this error, but admitted the mistake in a press release in April 1997. (See Jones, Citizens for a Sound Economy, May 1997 for a detailed analysis.) If we use 18.7ug/m3 as the risk threshold, the non-California Waldo practically becomes invisible relative to the California Waldo. The relative exposure risk for the California Waldo is now 93% of the total U.S. exposure risk.

Another way to put it is that Waldo is about 14 times larger in California than the rest of the Nation. There are even more shades of color to look at when trying to find Waldo.

Not all of the people who reside within a particular county have the same exposure as indicated by the design value, which is based on the worst monitored PM 2.5 level. EPA's non-attainment documentation sheds some light on this fact. For example, in the non attainment counties that are associated with the Chicago, Pittsburgh and the Baltimore/D.C. metro areas only about 50% of the monitors within these counties measured annual average PM 2.5 levels above 15 ug/m3. In the LA basin the percent above the NAAQS was 69. In all of Ohio it was 67. Surely all of the folks living in the smaller counties with only one monitor are more than likely not equitably exposed to that county's single design value. It is therefore appropriate to adjust the 57.7 million people Waldo cited at the beginning of this discussion downward to account for intra county exposure differences. A correction factor of 60% was assumed for illustration purposes yielding a nationwide Waldo of 34.6 million. Actually, EPA has the ability to define more precisely the Nation's population exposure distribution. They can actually model estimated exposures down to the census tract level, especially in major population centers where multiple monitoring sites exist. EPA has conducted such modeling for assessing the potential exposure to most of the air toxic pollutants of concern. (See the National Air Toxics Assessment, NATA) Such a census tract level analysis for PM 2.5 already exists in part in EPA's Clear Skies benefits analysis although not specifically to describe Waldo. For sure we can say that today's Waldo is not 99 million and probably less than the 35 million we have described so far. How will Waldo shrink in the future?

For starters current regulatory programs, mainly auto emissions reductions; have reduced the contribution of secondary aerosols (which are formed in smog) to urban PM 2.5. This reduction should continue commensurate with the turnover of the mobile source fleet to newer lower emitting vehicles. Nationwide average PM 2.5 has declined by 10% in the past four years according to EPA's own trend analysis. There is no reason to suggest that this same trend will not continue for at least the next 10 years. If such a trend holds true, all of the current design values can be reduced by 15% over the next six years, i.e. 2.5% per year based on the trend over the past four years. Based on this assumption the non California Waldo will only embrace some 14 million persons i.e. those persons living in the 12 counties which currently have PM 2.5 design values above 17.6 ug/m3. If we apply the 60% correction for monitoring differences as previously discussed; the non-California Waldo becomes a shadow of only 8.4 million. On the other hand this projected trend in reduced PM 2.5 has little or no effect in California. Ten of the 13 counties currently designated as in non-attainment will remain so with a population of 18 million (or 11 million corrected). Still the whole Waldo will shrink from EPA's bloated Waldo of 99 million to about 20 million without any further regulatory action. In health risk terms if we assume that the PM 2.5 NAAQS of 15 ug/m3 is the binding health effects threshold, the non California Waldo shrinks to only 15% of the California exposure risk in 2010. If we were to use EPA's assigned equivalent threshold of 18.7 ug/m3, the non-California risk would be ZERO. The California risk will be reduced by 62% by 2010 if the current trend continues.

The two regulatory strategies that EPA points to which they claim will help non-attainment areas achieve the PM 2.5 standard are the Interstate Rule and the Clean Air Non Road Diesel Rule. The Interstate Rule is essentially the same as the Clear Skies Initiative that was submitted to Congress but not acted upon. The Rule focuses on reducing SOx and NOx from coal fired power plants in the eastern half of the U.S. The modeled PM 2.5 reduction averaged less than 1 ug/m3 across the domain of the power plant impacts. There are no benefits from this Rule in California since there are no coal fired power plants in the State. Hence this Rule does nothing to reduce the health risk where it is the dominant risk nationally. The non-road diesel Rule will only reduce PM 2.5 by about 0.33 ug/m3 on the average by 2010. (See the Regulatory Impact Analysis on this Rule) Again this incremental ambient reduction will not significantly reduce the exposure risk in California nor change the non-attainment picture there. This Rule is not needed elsewhere in the Nation.

So " Where is Waldo?" In EPA's mind he is almost as big as the cartoon in which he's hiding i.e. 99 million in a total U.S. population of over 260 million persons. When Waldo's image is redrawn using some minimal degree of perfection and some shading he becomes almost obscure from sight. So when you look for Waldo look more carefully at the cartoon EPA is showing you.

Kay Jones is a private consultant in Seattle, WA. He has previously served as the senior advisor on air quality at the President's Council on Environmental Quality during the Ford and Carter administrations. This column is based on a longer article that will appear in the winter 2004 issue of Regulation magazine.


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