Welfare Risk and Exposure Assessment for Ozone Final This page intentionally left blank. EPA-452/R-14-005a August 2014 Welfare Risk and Exposure Assessment for Ozone Final U.S. Environmental Protection Agency Office of Air and Radiation Office of Air Quality Planning and Standards Health and Environmental Impacts Division Risk and Benefits Group Research Triangle Park, North Carolina 27711 DISCLAIMER This document has been prepared by staff from the Risk and Benefits Group, Health and Environmental Impacts Division, Office of Air Quality Planning and Standards, U.S. Environmental Protection Agency. Any findings and conclusions are those of the authors and do not necessarily reflect the views of the Agency. Questions on this document should be addressed to Dr. Bryan Hubbell at the U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards, 109 TW Alexander Drive, C504-02, Research Triangle Park, North Carolina 27711 or email -- [email protected]. TABLE OF CONTENTS 1 INTRODUCTION.......................................................................................................... 1-1 1.1 HISTORY ........................................................................................................................ 1-2 1.2 CURRENT RISK AND EXPOSURE ASSESSMENTS: GOALS AND PLANNED APPROACH .................................................................................................................... 1-4 1.3 ORGANIZATION OF DOCUMENT ............................................................................. 1-5 2 FRAMEWORK ............................................................................................................. 2-1 2.1 O3 CHEMISTRY ............................................................................................................. 2-2 2.2 SOURCES OF O3 AND O3 PRECURSORS ................................................................... 2-4 2.3 ECOLOGICAL EFFECTS .............................................................................................. 2-5 2.4 ECOSYSTEM SERVICES .............................................................................................. 2-8 3 SCOPE ............................................................................................................................ 3-1 3.1 OVERVIEW OF RISK AND EXPOSURE ASSESSMENTS FROM PREVIOUS REVIEW .......................................................................................................................... 3-2 3.1.1 Exposure Characterization ................................................................................... 3-3 3.1.2 Assessment of Risks to Vegetation ...................................................................... 3-4 3.2 OVERVIEW OF CURRENT ASSESSMENT PLAN .................................................... 3-5 3.2.1 Air Quality Considerations .................................................................................. 3-6 3.2.2 Relative Tree Biomass Loss and Crop Yield Loss .............................................. 3-8 3.2.3 Visible Foliar Injury ........................................................................................... 3-11 3.3 UNCERTAINTY AND VARIABILITY ....................................................................... 3-13 4 AIR QUALITY CONSIDERATIONS ......................................................................... 4-1 4.1 INTRODUCTION ........................................................................................................... 4-1 4.2 OVERVIEW OF O3 MONITORING AND AIR QUALITY .......................................... 4-1 4.3 OVERVIEW OF AIR QUALITY INPUTS TO RISK AND EXPOSURE ASSESSMENTS .............................................................................................................. 4-4 4.3.1 Air Quality Metrics .............................................................................................. 4-5 4.3.2 Ambient Air Quality Measurements .................................................................... 4-7 4.3.3 National-scale Air Quality Surfaces for Recent Air Quality ............................... 4-8 4.3.4 Air Quality Adjustments to Meet Existing Primary and Potential Alternative Secondary O3 Standards ..................................................................................... 4-10 4.4 ASSESSMENT OF UNCERTAINTY .......................................................................... 4-29 4.5 SUMMARY OF AIR QUALITY RESULTS ................................................................ 4-43 4.6 REFERENCES .............................................................................................................. 4-43 v 5 O3 RISK TO ECOSYSTEM SERVICES .................................................................... 5-1 5.1 INTRODUCTION ........................................................................................................... 5-1 5.2 REGULATING SERVICES ............................................................................................ 5-3 5.2.1 Hydrologic Cycle ................................................................................................. 5-3 5.2.2 Pollination ............................................................................................................ 5-4 5.2.3 Fire Regulation..................................................................................................... 5-4 5.3 SUPPORTING SERVICES ............................................................................................. 5-8 5.3.1 Net Primary Productivity ..................................................................................... 5-8 5.3.2 Community Composition and Habitat Provision ................................................. 5-9 5.4 PROVISIONING SERVICES ....................................................................................... 5-10 5.5 CULTURAL SERVICES .............................................................................................. 5-14 5.5.1 Non-Use Services............................................................................................... 5-15 5.6 QUALITATIVE ASSESSMENT OF UNCERTAINTY ............................................... 5-17 5.7 KEY OBSERVATIONS ................................................................................................ 5-21 6 BIOMASS LOSS ............................................................................................................ 6-1 6.1 INTRODUCTION ........................................................................................................... 6-1 6.2 RELATIVE BIOMASS LOSS ........................................................................................ 6-2 6.2.1 Species-Level Analyses ....................................................................................... 6-7 6.3 COMMERCIAL TIMBER EFFECTS ........................................................................... 6-23 6.4 NON-TIMBER FOREST PRODUCTS ......................................................................... 6-33 6.4.1 Commercial Non-Timber Forest Products ......................................................... 6-36 6.4.2 Informal Economy or Subsistence Use of Non-Timber Forest Products .......... 6-38 6.5 AGRICULTURE ........................................................................................................... 6-40 6.5.1 Commercial Agriculture .................................................................................... 6-40 6.6 CLIMATE REGULATION ........................................................................................... 6-48 6.6.1 National Scale Forest Carbon Sequestration ...................................................... 6-48 6.6.2 Urban Case Study Carbon Storage .................................................................... 6-50 6.7 URBAN CASE STUDY AIR POLLUTION REMOVAL ............................................ 6-55 6.8 ECOSYSTEM-LEVEL EFFECTS ................................................................................ 6-59 6.8.1 Potential Biomass Loss in Federally Designated Areas .................................... 6-63 6.9 QUALITATIVE ASSESSMENT OF UNCERTAINTY ............................................... 6-64 6.10 KEY OBSERVATIONS ................................................................................................ 6-72 7 VISIBLE FOLIAR INJURY ......................................................................................... 7-1 7.1 INTRODUCTION ........................................................................................................... 7-1 7.1.1 Ecosystem Services .............................................................................................. 7-4 7.2 NATIONAL-SCALE ANALYSIS OF FOLIAR INJURY ........................................... 7-10 vi 7.2.1 Forest Health Monitoring Network .................................................................... 7-10 7.2.2 NOAA Palmer Z Drought Index ........................................................................ 7-12 7.2.3 Results of National-Scale Analysis .................................................................... 7-13 7.3 SCREENING-LEVEL ASSESSMENT OF VISIBLE FOLIAR INJURY IN 214 NATIONAL PARKS ..................................................................................................... 7-19 7.3.1 Screening-Level Assessment Methods .............................................................. 7-20 7.3.2 Screening-Level Assessment Results and Discussion ....................................... 7-25 7.3.3 Sensitivity