1.	Why does the Air Resources Board (ARB) want to reduce diesel particulate matter (diesel PM) emissions from equipment used in agricultural operations?
A:	Diesel PM reductions from agricultural engines are necessary to help in the effort to reduce Californian's exposures to diesel PM. In September 2000 the ARB approved the Diesel Risk Reduction Plan, a comprehensive plan that is designed to significantly reduce diesel PM emissions and the associated potential cancer risks. The plan is a commitment for action over the next five to seven years and sets an ambitious goal to reduce current diesel PM emissions and their associated potential cancer risk levels by 75% in 2010 and by 85% or more in 2020. To meet this goal all uses and categories of diesel-fueled engines need to be examined and controls implemented where it is determined to be technically and economically feasible. Agricultural engines are not being singled out, ARB staff are looking at all applications - on-road, off-road and stationary engines to see what is the best way to reduce the diesel PM emissions and meet the Plan's goal.
2.	What percentage of the 2000 statewide diesel PM emissions inventory does diesel PM emissions from agricultural operations represent?
A:	Based on the ARB's diesel PM emission inventory for the year 2000, agricultural operations (which does not include emissions from logging operations) represent approximately 14 percent of the total 2000 statewide diesel PM emissions inventory. Diesel PM emissions from agricultural operations are comparable to those from on-road heavy-duty trucks which comprise approximately 16 percent of the total statewide diesel PM emissions for the year 2000.
3.	What is ARB's strategy for addressing the federal exemption for new farm equipment less than 175 horsepower, i.e., Federal Clean Air Act (CAA), Section 209 (e)(1)(A)?
A:	As the question indicates, we must rely on U.S. EPA to establish emission limits for new farm equipment because we are preempted by federal law from establishing emission limits for new farm equipment less than 175 horsepower. Recent developments suggest that off-road engine control can move directly to after-treatment technology-based standards with higher emission reductions, on a cost-effective per engine basis. To this end, we are encouraging U.S. EPA to accelerate the implementation of stringent emission standards in all 50 states based on after-treatment technologies with the goal of reducing diesel PM emissions to 90 percent.
4.	What regulatory approach will the ARB take to reduce diesel PM emissions from agricultural diesel-fueled engines?
A:	We will evaluate a variety of approaches for reducing diesel PM from agricultural equipment ranging from the traditional "command and control" approach to voluntary and incentive based programs. We believe that for new equipment, it makes sense to have a mandatory program that the original equipment manufacturers would need to meet at the national level. For retrofit applications, based on our initial discussions with agricultural representatives, we expect that less traditional approaches such as incentive and voluntary programs will result in a high level of compliance at the least cost to the agricultural industry. Regardless of the approach taken, however, measures to reduce diesel PM from agricultural equipment will be developed in an open and public process and we will continue to encourage input from the agricultural community.
5.	Can you shed some light on your intentions for the agricultural industry in the near-term?
A:	In the near-term, we will be focusing our efforts on identifying ways to reduce diesel PM emissions from new and existing agricultural tractors and irrigation pumps. These two uses of agricultural equipment are responsible for over 97% of the diesel PM emissions from all agricultural equipment and it makes sense to start by looking at these engines. For new engines, we will work with U.S. EPA to develop new engine standards that the manufacturers must meet. For the existing engines, we are beginning the process of identifying where we think retrofits will work and where it will be cost effective. To help us with this work, a Diesel PM Agricultural Working Group (see last question) has been created and we have enlisted their help in identifying where it will make sense to require retrofits, what incentive or voluntary type programs will best serve the needs of the agricultural community and what demonstration studies are needed to provide the confidence that the retrofits will work. We are also working closely with manufacturers to ensure any retrofits will address compatibility and warranty concerns.
6.	What technologies are available to reduce diesel PM emissions from existing diesel-fueled engines?
A:	Retrofits of existing diesel-fueled engines are an essential element of the Diesel Risk Reduction Plan. Over the next several years a significant percent of the reductions in diesel PM will result from retrofits. There are many control technologies available to reduce diesel PM emissions from in use diesel-fueled engines, the most effective being catalyst based diesel particulate filters (DPFs). DPFs have been demonstrated to reduce diesel PM emissions by 85 percent or more when used with very low sulfur (15 ppm) diesel fuel. During the development of the Diesel Risk Reduction Plan, ARB staff evaluated several technologies that can be used to reduce diesel PM emissions including the DPFs, alternative fuels such as biodiesel, engine modifications, fuel borne catalysts, oxidation catalysts and other types of particulate traps. Their findings are provided in Appendix IX of the Diesel Risk Reduction Plan.
7.	How much will catalyzed-based DPFs cost? How will you take into consideration the unique production costs California farmers face?
A:	When we developed the Diesel Risk Reduction Plan we worked with manufacturers of DPFs to estimate the costs associated with retrofitting off-road engines with DPFs. At that time, the costs to retrofit off-road engines ranged up to $30 per horsepower. This is an estimate based on the cost of retrofitting a wide range of engine types and applications. New data obtained after the Diesel Risk Reduction Plan was approved indicates this is likely an overestimate. We also expect the cost of DPFs to decrease significantly as production volume increases over the next several years. More representative and accurate cost estimates will be prepared during the development of each proposed measure. We will also work closely with the agricultural community through the Diesel PM Agricultural Working Group to take into consideration costs unique to agriculture. Even so, we remain sensitive to the cost impacts on California agricultural businesses. Retrofits will be put in place only when the cost is reasonable and we will work to develop and support incentive programs to help offset the cost of installing the equipment.
8.	To what degree are you going to take into consideration the operating conditions and useful life of agricultural equipment?
A:	Operating conditions, such as the hours of operation, age of equipment and location of equipment are important elements in our evaluations to determine the feasibility and cost effectiveness of implementing emission controls for diesel PM. As we move forward with implementation, we will work closely with the Diesel PM Agricultural Working Group and other agricultural representatives to obtain accurate information about operating parameters in California that we can then use in the decision-making process.
9.	How will you know that DPFs will work on equipment used in agricultural operations and what precautions are being undertaken to ensure that the use of DPFs or low sulfur fuel will not adversely affect our engines?
A:	While DPFs have been successfully used in many on-road applications, particularly in Europe, we are undertaking several demonstration programs to ensure a high level of confidence. Currently we are working with the Diesel PM Agricultural Working Group to identify which engines and applications would be the best candidates for a demonstration program. Once we have identified the best candidate engines we will design and conduct a study, in cooperation with the agricultural community, to help us better understand the applicability of DPF technologies and low sulfur fuel on agricultural equipment. In addition, in order to assist the manufacturers of retrofit emission controls and to provide assurance to the end user of DPFs, the ARB is developing a verification procedure for DPFs. Manufacturers of DPFs must provide data to verify reductions from equipment-based emission control systems; meet minimum performance and durability specifications as well as minimum defects warranty periods.
10.	What steps are being taken to ensure that adverse environmental impacts do not result from disposal from ash that has been collected on DPFs?
A:	DPFs are designed to oxidize the particulate matter to carbon dioxide; however, metal oxide "ash" particles remain trapped by the filter since these particles are not combustible. Metal oxide deposits that are found in the ash are derived from engine wear, oil additives, fuel additives, and corrosion of the manifold and other exhaust system components. Depending on the application, DPFs will need to be periodically cleaned to remove accumulated ash. It appears that a variety of practices are in use to accomplish this maintenance requirement, some which may result in release of potentially toxic substances into the environment. To ensure any adverse environmental impacts are minimized, ARB staff is working with the California Department of Toxic Substances Control to determine if the ash constitutes a "hazardous waste" under current State or federal laws and what maintenance and disposal procedures should be followed.
11.	Are there certain older engines, regardless of size, that will be exempt from our regulatory development efforts?
A:	It is premature at this time to identify any engines that will not be good candidates for retrofits. We need to conduct a thorough evaluation of agricultural equipment and what technologies are feasible and cost effective before we can identify which engines will be exempt. It is likely, however, that for some older, less frequently used equipment we will determine that it is neither feasible nor cost-effective to require this equipment to be retrofitted. In these cases, incentive programs to speed the introduction of newer equipment may prove to be a more suitable approach.
12.	The Diesel Risk Reduction Plan requires the use of very low-sulfur (<15ppm) diesel fuel. What quantity of diesel fuel with a sulfur content of no more than 15 ppm is being produced now, when will it be available throughout California and what will it cost?
A:	Approximately 20 percent of diesel fuel currently produced in California has a sulfur content, by weight, less than 15 ppm. ARB staff has estimated an incremental refining cost of less than $0.05 per gallon to produce this fuel. Under a current proposal to amend the California diesel fuel regulations, by June 1, 2006, all diesel fuel sold in California will have a sulfur content less than 15 ppm. We are aware of the concerns regarding the impact of the proposed fuel regulations on diesel supply and prices and ARB staff are evaluating several options that would help to mitigate these issues. In the event the ARB develops measures to reduce diesel PM prior to 2006 that would rely on the use of low sulfur fuel, we will take into consideration both the cost and availability of low sulfur fuel prior to proposing the measure to the ARB for consideration.
13.	Is the ARB aware of the existing economic disadvantage California farming operations face from their national and international competitors?
A:	We are sensitive to the competitive issues that are raised in the event there are "California" only requirements. To this end we are working closely with U.S. EPA to encourage them to adopt standards and regulations applicable to all 50 states that are similar in both scope and stringency to the measures identified in the Diesel Risk Reduction Plan. We also acknowledge it will be more difficult to create a "level playing field" with our international counterparts. To help minimize the competitive disadvantages within both the national and international marketplace we will be exploring the use of incentive programs and other voluntary type measures to lesson the economic burden on California farmers.