EPA’s Lead Modeling Study at the Santa Monica Airport Kim Hoang, PhD, MPH EPA Region 9

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,

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 November 30,

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,

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

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,

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,

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

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

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,

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,

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.

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,

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,

Comments on ANPR  ANPR in Federal Register at:  Comment period closed on Aug 27, 2010  However, comments are still accepted. Please follow instruction on Federal Register notice to submit comments. November 30,

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:  EPA actions with regard to responding to the petition from Friends of the Earth can be obtained from: November 30,

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 Ph: (415) Fax: (415) November 30,