Risk Screening of Point Source Air Toxics in Minneapolis/ St. Paul, Minnesota

1. Risk Screening of Point Source Air Toxics in Minneapolis/St. Paul, Minnesota Michele Knox Palmer Environmental Engineer Integrated Air Toxics Section EPA Region V, Chicago, IL April 8, 2008

2. Outline • Background on Air Toxics Program • Risk Screening Process and Tools • Minneapolis/St. Paul Case Study • Risk Screening • Monitoring Data • Conclusions • On-line Resources

3. What are Air Toxics? • 187 Hazardous Air Pollutants identified in the Clean Air Act 112(b) • Many are known or suspected carcinogens • May cause damage to • respiratory, reproductive, immunological • neurological or hormonal systems • Examples include benzene, metals, dioxins

4. What are Sources of Air Toxics? • Point Sources • Large and small Industries • Area Sources • Gas stations and dry cleaners • Mobile Sources • Cars, boats, planes and trucks • Natural Sources • Wildfires and volcanoes

5. What are US EPA’s Air Toxics Program Goals? • Further understand and characterize human health risks • Reduce human health risks due to exposure to air toxics • Utilize a combination of • technology-based standards • risk-based programs • voluntary reduction initiatives

6. What are Region V’s Regional Air Toxics Priority Projects? • Pursue voluntary initiatives to reduce point source air toxics • Collaborate with each of Region 5 States • Begin with a screening process to identify sources and risks • Work jointly with industries to achieve emissions reductions

7. What Tools are Available? • Risk Screening Software and Databases • NATA - National Air Toxics Risk Assessment • RSEI - Risk Screening Environmental Indicators • Ambient Air Monitoring Data • Emissions Inventory Databases • TRI - Toxics Release Inventory • NEI - National Emissions Inventory • RAPIDS – Regional Air Pollutant Inventory Development System • State and Local Inventories

8. Description of Tools • NATA and NEI • Every 3 years, 1996,1999, 2002 2002 NATA coming soon • Point, area and mobile sources • RSEI and TRI • Every year, RSEI through 2005, TRI through 2006 • Point sources only • Industry self reporting

9. Air Toxics Risk Screening Process R. Trine, IATS, 2007

10. Air Toxics Risk Screening Process (continued) R. Trine, IATS, 2007

11. So What is Going on in Minneapolis/St. Paul?

12. Minneapolis/St. Paul Study Area • Included 5 counties for analysis • Hennepin, Ramsey, Washington, Dakota, Anoka • Encompasses half the population of Minnesota • In general, highest health risks are where the people are most concentrated

13. NATA Cancer Risks in Minnesota

14. NATA Non-Cancer Hazard in Minnesota

15. RSEI Score of Pollutants (2000-2005, unitless relative score) C = metal compounds

16. TRI Air Toxics Emissions (pounds, 2000-2005) C = metal compounds

17. Diisocyanate Emissions by Source

18. Diisocyanates Follow-up • US EPA met with the State • State consulted Industry A • Industry A realized it was incorrectly over-reporting DI emissions • No significant risks from Diisocyanates • Continued with our evaluation of nickel and manganese emissions

19. Evaluating Risks and Emissions of Manganese (Mn) and Nickel (Ni) • RSEI shows that manganese and nickel are the next highest sources of risk • We can apportion risks by industry • We can view air monitoring data for metals • Risks are relative to population in proximity to source as well as overall emissions

20. Air Toxics Risk Screening Process R. Trine, IATS, 2007

21. Monitoring Sites for Metals (TSP) TSP=total suspended particulates

22. How do we Evaluate Health Risks from Monitoring Data? • Compare ambient concentrations to health standards • HQ < 1 considered “safe” • RfC - Reference Concentration for non-cancer • Conc/RfC = Hazard Quotient (HQ)

23. Air Monitoring Results for Twin Cities (2000-2007, ug/m3, TSP) TSP = total suspended particulates C = metal compounds * IRIS and ATSDR

24. So . . . What does all this mean? • RSEI analysis shows that nickel (Ni) and manganese (Mn) are two pollutants which may be of concern in Minneapolis/St. Paul • Monitoring data is available that shows that Mn levels may be elevated in the urban area • Ni and Mn emissions may contribute to total health risks in the urban area

25. Where do we go from here? • Verify data from manganese and nickel emissions sources • Coordinate with the State to evaluate the significance of this data and determine a future course of action • If necessary, work with the State and identified industries on possible voluntary nickel and manganese emission reductions

26. Conclusions • NATA and RSEI can be used to prioritize pollutants, industries and geographic areas of concern • Monitoring data can be compared to health standards to show which pollutants are elevated • Data must be evaluated critically with good science and sound judgment in light of the inherent uncertainties in screening tools • These tools can guide us in making decisions on how to achieve public health risk reductions

27. On-line Resources • NATA – www.epa.gov/ttn/atw/NATA • RSEI – www.epa.gov/opptintr/rsei/ • Monitoring – www.epa.gov/air/data/reports.html • NEI – www.epa.gov/ttn/chief/net/index.html • TRI – www.epa.gov/triexplorer • RAPIDS – glc.org/air/rapids/