BOARD MEETING DATE: November 7, 2003
AGENDA NO. 16

Report on Ambient Air Quality Evaluation to Determine Relative Contribution of Internal Combustion Engines Used for Manufacture of Snow or Operation of Ski Lifts to Potential PM_2.5 Violations

SYNOPSIS:

Rule 1110.2 – Emissions from Gaseous- and Liquid-Fueled Engines, required the Executive Officer to report to the Board by December 31, 1999 on the relative contribution of engines which operate for the manufacture of snow and/or operation of ski lifts to potential PM_2.5 violations. The original report and an update were submitted and accepted by the Board in November 1999 and December 2001, respectively. The current report is an update to the previous two and, similar to prior years, no violations of PM_2.5 standards occurred.

COMMITTEE:

Stationary Source, September 26, 2003, Reviewed

RECOMMENDED ACTION:

Receive and file.

Barry R. Wallerstein, D.Env.
Executive Officer

Introduction

Rule 1110.2 – Emissions from Gaseous- and Liquid-fueled Internal Combustion Engines sets limits for oxides of nitrogen, carbon monoxide, and volatile organic compounds from internal combustion engines. A 1997 amendment to the rule exempted diesel engines used for snow manufacturing and ski lift operation in the Big Bear area. It also required a report to the Board on the relative contribution of these engines to potential PM_2.5 violations. The first report was in November 1999 and included a commitment by staff to update the report every two years. The first update was submitted to the Board in December 2001. The 1999 report and 2001 update concluded that the PM_2.5 concentrations in the Big Bear area where the engines operate were well below the federal standards. Over the past two years, the concentrations have remained below the federal standards. The state of California recently adopted a standard for annual average PM_2.5 concentrations and the Big Bear area also complies with the new state standard.

Background

Rule 1110.2 – Emissions from Gaseous- and Liquid-fueled Internal Combustion Engines sets limits for oxides of nitrogen, carbon monoxide, and volatile organic compounds from internal combustion engines. A 1997 amendment to the rule exempted diesel engines used for snow manufacturing and ski lift operation in the Big Bear area. It also required a report to the Board on the relative contribution of these engines to potential PM_2.5 violations.

PM_2.5 samples from a monitoring station near the ski areas were studied and the report required by the rule was submitted to the Board in November 1999. While concentrations during the ski season were found to be slightly higher than in the off-season, it was noted that other factors must also be considered. Increased diesel truck and automobile traffic during the ski season and the use of wood-burning stoves and fireplaces during cold weather also produce PM_2.5 emissions. The report concluded that PM_2.5 concentrations in the area were below the National Ambient Air Quality Standard (NAAQS) for PM_2.5 for both the 24-hour standard and the annual arithmetic mean. The original report recommended no changes to Rule 1110.2, continued PM_2.5 monitoring in the Big Bear area to assure compliance, and updates on the report to the Board every two years. A subsequent update report was made in December 2001 with similar conclusions and showing no violations of the federal PM_2.5 standards. Recently, a new annual arithmetic mean for ambient PM_2.5 concentrations was adopted by the State of California. Although the new standard is lower than the federal standard, the previous data shows no exceedance of the state standard, as well.

Current Status of PM_2.5 Compliance in the Big Bear Area

As with the previous reports, this update is based on analysis of PM_2.5 samples from the Big Bear monitoring station located at the Big Bear Airport. The ski areas are located south and southeast of the airport within two to four miles of the monitoring station. The original report studied eight months of data because the sampling station was installed in early 1999. The 2001 update included nearly three years of data. This update includes approximately four and one-half years of data, from February 1999 through June 2003. As with the previous assessments, no violations of the federal 24-hour or annual arithmetic mean for PM_2.5 were recorded. The highest concentration recorded at Big Bear since sampling began in 1999 was 35 micrograms per cubic meter (ìg/m³). All samples were well below the federal 24-hour standard of 65 ìg/m³. There is no separate state 24-hour standard. The annual averages at Big Bear for 1999 (11 months of data), 2000, 2001, 2002, and 2003 (6 months of data) were 10.3, 10.5, 11.0, 11.3, and 9.8 ìg/m³, respectively. Figure 1 shows the annual average PM_2.5 for the five years. Again, these are below the federal annual arithmetic mean standard of 15 ìg/m³. The state of California recently adopted an annual average standard for PM_2.5 of 12 ìg/m³ which is lower than the federal standard, however, the Big Bear PM_2.5 annual averages are also below the new state standard.

Figure 1

Figure 2 shows the PM_2.5 daily ambient concentration at the Big Bear monitoring station from February 1999 through June 2003. The line at 65 ìg/m³ represents the NAAQS for PM_2.5 over a 24-hour period. All readings during the sampling period are below the standard. The state has no separate 24-hour standard for PM_2.5. The exemption for snow manufacturing/ski lift engines extends from November 1 of one year through April 15 of the following year. PM_2.5 concentrations are somewhat higher during that period than during the off-season. However, as noted in the original report, many factors contribute to increased PM_2.5 during the ski season, including internal combustion engines, increased truck and automobile traffic, and the use of wood-burning ovens and fireplaces in cold weather.

Other Considerations

This report focuses on the surrounding PM_2.5 concentrations contributed by the snow manufacturing/ski lift diesel engines. It does not address any other compliance issues related to these engines or any pending regulations regarding diesel engines in general. There are a few other issues involving diesel engines which should be noted, however. The 1997 amendment to Rule 1110.2 is still under review by U.S. EPA. Pending the outcome of that review, additional changes to the rule may be required. CARB has classified diesel exhaust as a toxic air contaminant and is working on standards for all diesel-fueled internal combustion engines which will eventually affect all existing and new diesel engines in the AQMD. Because of potential health effects due to diesel PM exposure, PM₁₀ emissions from new and modified diesel engines are subject to new source review requirements for toxic air contaminants including installation of Best Available Control Technology for toxic emissions (T-BACT), as well as BACT and other requirements of New Source Review rules for criteria pollutants.

There are two facilities covered by this report, Snow Summit and Bear Mountain. Recently, under Order for Abatement, Snow Summit has agreed to replace the portable diesel-fueled engines used for snow-making with two large diesel-fueled engines equipped with selective catalytic reduction and particulate filters. Six diesel-fueled engines installed approximately 20 years ago will continue to operate and produce power for several purposes, including snow-making. The engines used to operate the ski lifts will still be operated. Also, under Order for Abatement, Bear Mountain has converted their diesel engine driven snow-making operations to run on electricity. The two areas are now under the common ownership of Snow Summit although they maintain the original names.

Conclusions

No PM_2.5 exceedences of federal or state ambient air quality standards were found over the past four and one-half years in the Big Bear area. All 24-hour samples were below the federal standard and the yearly averages were also lower than the federal and state standards for annual average. Emission controls and electrification of many of the diesel-fueled engines used for the manufacture of snow will further reduce particulate emissions. No violations of the PM_2.5 standards were observed and no violations are anticipated based on the sampling data. However, since PM_2.5 emitted directly by internal combustion engines contains air toxic contaminants, particulate emissions from diesel engines will be regulated under a new state Air Toxics Control Measure for new and existing diesel engines proposed for adoption by CARB in November of this year. Diesel engines will also be subject to future AQMD rules. In addition, any new or modified engines are subject to new source review requirements for criteria and toxic air contaminants including, but not limited to, BACT and T-BACT, respectively.

Staff Recommendations

No change to Rule 1110.2 is recommended at this time based on continuing compliance with NAAQS for PM_2.5 in the Big Bear area. Continued PM_2.5 sampling is recommended to assure continued compliance in the area. Staff recommends that updates every two years be discontinued since over four years of data consistently shows compliance and emissions have decreased because of the changes at the ski resorts in the Big Bear area. One has electrified their engines and the other has controlled and upgraded engines.

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