PROPOSED RULE TO REGULATE OZONE

NCBA Staff Contact: 

Tamara Thies, Chief Environmental Counsel
202-347-0228

tthies@beef.org

Ozone is produced by a chemical reaction in the atmosphere between volatile organic compounds (VOCs) and oxides of nitrogen (NOx) in the presence of sunlight (i.e. VOC + NOx + sunlight = ozone).  The reactions occur on the scale of 1-2 hours after the VOCs and NOx emissions have mixed.  VOCs are defined as “any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions.” VOCs are emitted from livestock, vegetation burning, and animal waste handling and storage.  NOx is created when nitrogen from either fuel or air combines with oxygen from the air.  NOx is emitted from lightening, soil microbial activity, biomass burning, and fuel combustion from vehicles including farm equipment, among other sources.

The Clean Air Act directs the EPA to set a National Ambient Air Quality Standard (NAAQS) for ozone at a level that is protective of human health and the environment, and to regulate both VOC and NOx emissions as ozone precursors.  The EPA provides guidance for each state with areas not attaining the ozone NAAQS to develop its State Implementation Plan (SIP) to attain the standard by a required attainment date.  The current 8-hour ozone NAAQS is .084 parts per million (ppm).  EPA has issued a proposed rule to tighten the standard to .070-.075ppm during most of the year, and to regulate ozone even more stringently during the crop-growing season due to alleged ozone effects on crop yields.  NCBA wrote comments in opposition to the tightened standards.  EPA is expected to issue a final rule on the ozone standard on March 12, 2008.

NCBA believes that the currently available science, when interpreted properly, shows that the current NAAQS is requisite to protect the public health and that a tighter standard is not necessary.  NCBA has worked with a large coalition of interested organizations which has enlisted scientists to evaluate scientific studies on the issue.  The scientists have determined that the body of studies on which EPA relied to propose a tightened standard has not changed appreciably since EPA set the last standard in 1997.  What has changed, however, is that EPA has gone to extraordinary lengths to make its case for a tighter standard by “reinterpreting,” and we believe mischaracterizing, those studies.  The coalition submitted extensive comments outlining problems with EPA’s proposal. 

NCBA also objected to EPA’s proposal to tighten the ozone standard even more during the crop-growing season.  The fact is that despite the presence of ground-level ozone at or above the current NAAQS, yields for all the major crops have been increasing over the past decade, not decreasing by 50% or greater as chamber studies on which EPA relied predicted.  Chamber studies have little similarity to real world conditions.

In addition, NCBA urged the EPA to regulate VOCs based on their reactivity.  There are thousands of individual chemical species of VOCs that can undergo photochemical reaction in the presence of sunlight and oxides of nitrogen to form ozone.  Not all VOCs, however, contribute equally to ozone formation.  In fact, the ozone-forming potential, or reactivity, of different VOCs varies widely.  The EPA has made some attempts over the years to consider variations in VOC reactivity in its SIP policy and guidance.  These efforts led to the development of EPA’s exemption policy for negligibly reactive VOCs (compounds that are less reactive than or equally reactive to ethane), such as methane and acetone.  In 2005, the EPA issued an “Interim Guidance on Control of Volatile Organic Compounds in Ozone State Implementation Plans” which encourages States to consider recent scientific information on the photochemical reactivity of VOCs in the development of SIPs.  While NCBA agrees with EPA’s view that States should focus on reactivity for control measures, we believe the EPA should require States to regulate VOCs based on reactivity by 2013, the date by which SIPs are due for the new ozone NAAQS.  Scientists have made great progress over the years in determining VOC reactivity, and much more progress is likely to be made by 2013.  Any VOC that has been determined by respected scientists to be highly reactive should be controlled more stringently than VOCs that have been determined to have lower reactivity.  EPA should work to expand or contract the VOC reactivity list in the future as the science and knowledge base evolves to support such changes.  While NCBA understands that it is impossible for the EPA to regulate each VOC differently, we believe it is possible to regulate VOCs more appropriately than is currently done.  This approach is justified from environmental and economic standpoints.  Scarce resources from both public and private budgets would be focused on controlling compounds that have a larger impact on ozone formation, and exclude from or optimize regulation of those compounds that have minimal or no impact on ozone formation.  Return on investment in VOC control strategies would be maximized; and fewer funds would be wasted.

NCBA also urged the EPA to require that States by 2013 take into consideration the characteristics of the geographic area when applying the VOC reactivity-based policy.  If the purpose of the VOC control policy is to reduce ozone formation, scientists believe it is very important to determine the relative effectiveness of VOC and NOx controls in achieving that goal.  Scientists have determined that in some areas of the country, which are characterized as “NOx-limited,” reducing VOC emissions may have little or no impact on reducing ozone formation.  NCBA urged the EPA to perform the research necessary to determine the locations of these areas so that VOC control measures can be targeted to those geographic areas where controls are warranted, instead of requiring sweeping controls of VOCs across geographic areas that will do little or no good in decreasing ozone formation.

If the EPA decides to tighten the ozone standard, there may be many more ozone nonattainment areas around the country than currently exist.  This means that more areas will be required to control VOC and NOx emissions from their sources.  California currently requires CAFOs in nonattainment areas to develop and implement mitigation plans.  Research is currently ongoing at State universities to determine the VOC emission factor from beef cattle, and to develop effective BMPs to control these emissions.  Manure handling, diet manipulation, bedding options, moisture control, and lagoon controls for dairies, among others, currently are being assessed.