Status Report: “Significant Impact” from Mobile Sources and Road Dust By John F. Kowalczyk Co-Chair WRAP Mobile Source Forum WRAP Board Meeting Nov. 13, 2002

“Significant Impact” Requirements in Section 309 Determine if Mobile Source Emissions or Road Dust “Contribute Significantly” to Visibility Impairment in any of the 16 Class I areas on the Colorado Plateau based on Current and Projected Emissions.

If Mobile Sources from an Area of a State are a “Significant Contributor” Requires State to Restrict Emissions to Projected Lowest Levels Implement Measures to Achieve “Emissions Budget” and Demonstrate Compliance Establish Annual Emission Tracking System and Report in Required Periodic SIP Revisions (2008,2013,2018)

If Road Dust (Paved and Unpaved) is a “Significant Contributor” Must Implement “Necessary and Appropriate Emission Management Strategies”

Ambiguities of Rule “Mobile Sources Not Defined “Significant” Not Defined “Areas of State” Not Defined

Mobile Source Forum Recommendations Define “Areas of State” for purposes of Mobile Source Analysis as Urban areas in the 9 -State Transport Region with populations > 250,000 Analyze Road Dust Impacts on a Statewide/Reservation Basis No Consensus on Definition of “Significant” at this Time - Some Alternatives Identified

Remainder of Presentation Emission Trends Visibility Analysis Results Alternative Definitions of Significant Issues with Alternatives Possible Future Actions

Noteworthy Points Onroad, Nonroad and Total Mobile Emissions all Trend Downward in 309 Planning Period Further Reductions in Nonroad Emissions expected because of Imminent Revisions to Emission Model and Expected New Regulations

Cumulative Mobile Impact

Phoenix Area Mobile Impacts

Nonroad Most Significant Nonroad Emissions are Predominant cause of Visibility Impacts from Mobile Sources (about 80% of contribution) Nonroad Sources will continue to be of concern in the future even with revised model .

Agreement on Recommendations for Nonroad Support expeditious adoption/ implementation of new EPA reg. for Engines and Fuels similar to those for Onroad (WRAP LETTER?) WRAP (MSF) Coordinate regional demo projects/retrofit and clean fuel programs to reduce nonroad emissions

Six Alternative “Significance” Determinations Mobile Source Forum Originally Proposed 1 Cumulative and 2 Area approaches Recently 1 Emission Approach, 1 Additional Cumulative and 1 Additional Area Approach Identified

Original MSF Proposals for Defining Significant Impact Cumulative < 10%, Area >5% Cumulative >10%, Area >1% Urban Area > 1% Urban Area > 10%

Alternatives 1,2 & 3 for Phoenix Mobile Sources Cumulative : > 10%: 6 Class I areas > 1% (highest Class 1 area 8%) Area > 1%: 6 Class I areas > 1% Area >10% No Areas >10%

MS Forum Can’t Reach Consensus on 1st 3 Alternatives Alternatives felt to be either to Stringent or not Stringent enough. Finding Phoenix Has Significant Impact prevents 309 because of state legislation and may jeopardize entire 309 process - emission budget would not implemented - nothing accomplished

Cumulative Road Dust Impacts

Road Dust Recommendation Road Dust Impacts from any one state/reservation most likely not significant under any of 3 alternatives (max. cumulative impact ~ 3% Find Road Dust is not significant contributor to Visibility Impairment from any State/Reservation (< 1% impact)

Alternative 4 By MS Forum: Emission Trend Approach Intent of Haze Rule (309) (d) (5) (ii) and GCVTC Emission Budget Provision is to Prevent Future Emission Increases Total Mobile Source Emissions are projected to continually decrease through 2018 in all Urban Areas Conclude Mobile Sources are not Significantly Contributing to Visibility Impairment Per Rule Provision Intent

IOC Issues with Alternative 4 Downward Trend in Emissions does not necessarily mean Mobile Sources are not a Significant Contributor to Visibility Impairment Feel Nonroad component of Mobile Sources has a Major Impact on Visibility even with expected Change in Emission Model. Feel Rule may require an actual Visibility Model Analysis.

Alternative 5 Use total Visibility Impairment Analysis (natural background + human caused) Use Cumulative MS Forum Significance Alternative (Alternative 1) Consider reductions in Nonroad Emissions from imminent change in emission model Find Mobile Source Impacts Insignificant (All urban areas < 5% contribution

Issues with Alternative 5 May conflict with Rule definition which seems to require a Visibility Analysis based only on Human Caused Impairment Some concern about Message and Precedence of approach used in finding Mobile Sources have Insignificant Impact.

Alternative 6 Consider Intent of GCVTC that Emission Budget apply only to Onroad Emissions Consider it unreasonable to apply Emission Budget to Onroad Mobile based on most of Visibility Impact coming from Nonroad Mobile Emissions.

Alternative 6 (Continued) Use Visibility Modeling Analysis based on Human Impact only Use 5% as Significance Threshold (middle ground of MSF 3 alternatives and somewhat consistent with PSD and FLAG) . Conclude Onroad Mobile Sources from any Major Urban area have Insignificant (<5% impact)

Alternative 6 (Continued) Also Conclude Nonroad Visibility Impacts are Large even considering imminent Emission Model Revisions and support new Local,State and Federal Efforts to Control Nonroad Mobile Emissions as previously outlined.

Issues with Alternative 6 EPA must agree that rule intent was to analyze and apply emission budget to onroad mobile only. Not clear whether this would solve Arizona legislative problem with 309 process.

Possible WRAP Action Support one of the Alternatives Give MSF/IOC more time to try and reach consensus Direct MSF to prepare suite of some alternatives for States/Tribes to consider Do not provide any guidance to states/tribes other than emission and modeling results. Support Recommendations on Nonroad