1. EPA’s 2009-2010 Lead Modeling Study at the Santa Monica Airport Kim Hoang, PhD, MPH EPA Region 9

2. Acknowledgment Contribution to this presentation from:  Marion Hoyer, PhD Office of Transportation and Air Quality  Arnold Den, PhD Region 9 (retired)  Matt Lakin, PhD Region 9 November 30, 2011 2

3. Overview  Background nationally on lead emissions from piston-engine aircraft  Why we conducted a study at the Santa Monica Airport  Results of the study  Recommendation from this study  EPA web site on other major lead sources http://www.epa.gov/lead/index.html November 30, 2011 3

4. Inventory of Sources Contributing Lead to Ambient Air  Sources of lead emissions to air include:  Gasoline for piston-engine aircraft (not used in commercial passenger aircraft)  Metal industries  Manufacturing industries  Waste incinerators  Industrial/commercial/utility boilers  In 2008, these sources collectively emitted 990 tons  In 2008, 551 tons of lead were emitted due to use of leaded aviation gasoline.  Approximately half this lead is emitted in-flight  The other half is emitted in the local flying area around airports November 30, 2011 4

5. Airports Where Piston-engine Aircraft Operate in the U.S. November 30, 2011 5

6. Petition on Lead Emissions from Piston Aircraft  In 2006 Friends of the Earth Petitioned EPA to do the following:  If sufficient information exists, make a finding of the endangerment to public health and welfare.  If finding is positive, propose a lead emission standard for general aviation aircraft.  If insufficient information exists to make a finding, commence a study.  In 2007 we issued a notice requesting input on a wide range of issues regarding emissions of lead from piston aircraft.  In 2010 we issued an Advance Notice of Proposed Rulemaking (ANPR) to let people know we are studying this issue and requesting additional information. November 30, 2011 6

7. Primary Purpose of the EPA Study at Santa Monica  The goal of this study was to develop an approach to model ambient air lead concentrations near airports.  Lead emissions from piston-engine aircraft and leaded aviation gasoline are Federally-regulated.  EPA received a petition to determine whether lead emissions from piston-engine aircraft endanger human health and the environment.  The results of this study are being used to inform an EPA national-scale analysis of the local impact of lead emissions from piston-engine aircraft. November 30, 2011 7

8. 8 Description of Study (2008)  Collected limited air, soil and dust monitoring data  Collected a limited number of air samples to conduct a model- to-monitor comparison (3 days in summer and 3 days in winter)  Soil and dust monitoring to explore potential gradient of Lead relative to distance from airport  Collected data for air quality modeling  Detailed lead inventory for all sources within 25 Km of the airport, aircraft counts by hour, lead emissions locations on airport property, etc.  Modeled air lead concentrations for every day of 2008  provide maximum 3-month average lead concentrations for comparison to the Lead NAAQS November 30, 2011

9. Lessons Learned from the Air Monitoring  Average lead concentrations in air were in the same range as those reported by SCAQMD in 2006-2007  Concentrations at upwind locations (west tarmac) were at or below 0.004  g/m 3  Concentrations at downwind locations (east tarmac) ranged from 0.039 – 0.071  g/m 3  Concentrations at neighborhood sites downwind ranged from 0.033 – 0.056  g/m 3 November 30, 2011 9

10. Lessons Learned from the Air Modeling  Modeling results agreed well with monitored values – provides strong confidence for applying the model to other airports  Lead concentrations above the local background levels extended up to 500m downwind from the airport  The engine “run-up” check had a significant impact on ambient lead concentrations  This is important because we had not previously included run-up emissions in air quality modeling  Roadway dust was not a significant contributing factor to ambient lead levels near the airport November 30, 2011 10

11. Comparison of Modeled Lead Concentration Data to the Lead NAAQS  The Lead National Ambient Air Quality Standard (NAAQS) was revised in 2008 to a level of 0.15  g/m 3  The standard is measured as the maximum 3-month average concentration  We did not collect samples over a 3-month period to provide a relevant comparison to the modeled averages  Modeled concentrations for 2008 at two locations on airport property had 3-month average lead concentrations above 0.15  g/m 3  Cannot be used to determine attainment status  All the individual days monitoring data are lower than the modeled 3-month average values November 30, 2011 11

12. 12 Soil and Dust Sampling  We collected soil and dust samples on airport property, in local parks, and at local residences.  Results showed no elevated lead on airport property or in local parks, compared to average, non-source impacted levels in California.  Two home samples had lead levels above either the EPA or Draft CAL/EPA lead screening levels  Aviation lead may have contributed to these levels, but the results suggest additional sources may be involved.

13. Implications For Other Airports  Air monitoring and modeling approaches used for SMO fully applicable to other local scale airports  Multiple runways and prevailing wind directions might require additional data  Recommendation for other airports:  Conduct on-site survey of piston-engine aircraft activities  Collect hourly activity patterns  Use on-site wind speed and wind direction data  Use site-specific terrain and land use data  Include stationary sources within at least 20 km November 30, 2011 13

14. EPA’s Current Focus and Activity: Evaluating the Question of Endangerment  We are performing additional analyses as described in the ANPR:  Model piston-engine emissions of lead at airports to evaluate the impact on local air quality and exposure to lead  Evaluate the data from lead monitors  Issue a proposal describing our analysis and our proposed position on the question of endangerment.  Opportunity for public comment on our proposal before any action if finalized  Issue a final decision document. November 30, 2011 14

15. Comments on ANPR  ANPR in Federal Register at: http://federalregister.gov/a/2010-15340 http://federalregister.gov/a/2010-15340  Comment period closed on Aug 27, 2010  However, comments are still accepted. Please follow instruction on Federal Register notice to submit comments. November 30, 2011 15

16. Where to Obtain Information  The final report: “Development and Evaluation of an Air Quality Modeling Approach for Lead Emissions from Piston-Engine Aircraft Operating on Leaded Aviation Gasoline” (Feb 2010) for the EPA study at the Santa Monica airport is posted at: www.epa.gov/otaq/aviation.htm www.epa.gov/otaq/aviation.htm  EPA actions with regard to responding to the petition from Friends of the Earth can be obtained from: www.epa.gov/otaq/aviation.htm November 30, 2011 16

17. My Contact Information Kim Hoang, PhD, MPH Air Toxics Risk Coordinator Air Division U.S. EPA Region 9 (Air-6) 75 Hawthorne Street San Francisco, CA 94105 Ph: (415) 972-3147 Fax: (415) 947-3583 Email: hoang.kim@epa.gov November 30, 2011 17