Western Air: Progress and Challenges in Protecting Human Health and Scenic Vistas

1. Western Air: Progress and Challenges in Protecting Human Health and Scenic Vistas Chancellor’s Community Lecture Series Healing the West Mike Hannigan and Jana Milford Department of Mechanical Engineering University of Colorado at Boulder November 6, 2002

2. Acknowledgments • Pat Reddy, Colorado Department of Public Health and Environment • Pat McGraw, Colorado Department of Public Health and Environment • Chris Shaver, National Park Service • Jaime Lehner, Environmental Engineering, CU-Boulder • Kelly Allard, Environmental Engineering, CU-Boulder • Toni Newville, Mechanical Engineering, CU-Boulder

3. Road Map • Air Pollution and Health • Health-based standards • How is Denver doing? • The latest challenge: • Fine particles Photo credit: Shelly Miller

4. Road Map • Air Pollution and Visibility • Visibility goals • How is Denver doing? • How are scenic areas in the West doing? • What will it take to meet our visibility goals?

5. Air Quality Standards and Goals • National Ambient Air Quality Standards – criteria pollutants • Protect public health and welfare “with an adequate margin of safety” • Meant to protect sensitive populations • Margin of safety concept is questionable if no clear threshold exists (e.g., particulate matter) • Set by EPA administrator based on scientific data • field observations (particulate matter) • experimental data (ozone) • Standards to be set without regard to costs • Costs considered in implementation policies and timelines • Hazardous air pollutants – 1990 Amendments • 189 compounds • Goal: less than one in a million residual risk

6. National Ambient Air Quality Standards

9. Violation: 3-yr average > 85 ppb

11. 0.02 2.5 10 0.1 (diameter in mm) Size Distribution of Airborne PM fine coarse ultrafine amount size

12. human hair coarse particle fine particle ultrafine particle . How small is that? 10,000 mm = 1 cm If we zoom in,

13. Size Distribution of Airborne PM coagulation fine coarse mechanical processes ultrafine # • wind blown dust • road sand • brake wear • leaf debris size condensation processes accumulation processes • atmospheric reactions • combustion 0.02 2.5 10 0.1 • coagulation • condensation on existing particles • √ combustion and atmospheric reactions (diameter in mm) PM Origins

14. 0.02 2.5 10 0.1 (diameter in mm) PM10 includes … PM2.5 includes … Vocabulary Size Distribution of Airborne PM fine coarse ultrafine # size

15. So, what happens when breathe these particles in? Lungs are a series of these branches. ~7 in all, each getting smaller. coarse particle

16. . ultrafine particle So, what happens when breathe these particles in? Lungs are a series of these branches. ~7 in all, each getting smaller. Fine particles go deep into lungs, so this worries us.

17. Increases in ozone not associated with increases in death. Increases in PM2.5 are associated with increases in death. Acute effects. OK, so how bad is it? Results from the 6-cities study. SO, high PM2.5 levels can cause immediate health problems. Dockery et al., N. Engl. J. Med., 329:1753-1759.

18. 1.00 means no increased risk There is significant risk of death from cardiopulmonary problems and lung cancer due to PM2.5 levels in the US urban areas. Total Mortality Chronic effects Cardiopulmonary Mortality Relative Risk Lung Cancer Mortality If you live in a US urban area, the risk associated with PM2.5 is similar to the risk of being moderately overweight. Other Mortality PM2.5 Ozone Total PM Pope et al., JAMA, 287: 1132-1141, 2002

19. Hard to say much about trends with any degree of confidence.

20. If we were to use the numbers from that study, along with western air pollution values … (50) (100) (310) (110) (860) (450) (200) (1560) Total = 3500 deaths/year (1200-6200 – 95% confidence)

21. Los Angeles Denver Still motor vehicles are King! So, can we be more specific about the origin of PM2.5? Differences may be due to technique. Source: NFRAQS (1999)

22. Visibility: Downtown Denver Grand Canyon National Park

23. Visibility Goals • Regional Haze • 1977 Clean Air Act Amendments Set goal of returning visual air quality to natural conditions in 156 National Parks and Wilderness Areas • 1990 Clean Air Act Amendments Emphasized regional nature of problem • 1999 Regional Haze Rule: Return to natural visibility conditions by 2065 • Denver-Metro Visibility Standard • State standard, established in early 1990s • Set by study of Denver residents’ views on acceptable visual air quality • Not federally enforceable

24. uv microwave infrared x-rays radio radar tv visible 1 nm 10 nm 100 nm 1 mm 10 mm 100 mm 1 mm 1 cm 1 m 100 m 1 km 1 mm 200 nm 800 nm 2 mm wavelength Size distribution of energy from the sun Why do we call this energy type ‘visible’? We can see it! So, what does that make our eyes? Highly evolved energy detectors.

25. Size Distribution of Airborne PM # 0.02 2.5 10 0.1 (mm) Now, overlay the solar energy size distribution over the typical particle size distribution. Fine particles are similar in size to visible light, and, in general, the solar spectrum. SO, these particles impact visibility and solar radiation.

30. One-hour extinction at 3 PM = 0.026 km-1 (standard = 4-hour average of 0.076 km-1) Photo courtesy of Pat Reddy, CDPHE

31. One-hour extinction at 1 PM = 0.078 km-1 (standard = 4-hour average of 0.076 km-1) Photo courtesy of Pat Reddy, CDPHE

32. One-hour extinction at 11 AM = 0.682 km-1 (standard = 4-hour average of 0.076 km-1) Photo courtesy of Pat Reddy, CDPHE

34. Grand Canyon National Park Mount Trumbull viewpoint Bext = .041 km-1 Visual Range = 95 km Bext = .010 km-1 Visual Range = 390 km Source: IMPROVE network

35. Visibility Trends at Grand Canyon National Park Source: U.S. EPA

36. Weiminuche Wilderness Bext = .011 km-1 PM2.5 = 0.2 ug/m3 Bext = .130 km-1 PM2.5 = 23.6 ug/m3 Source: IMPROVE network

37. Visibility Trends at Weiminuche Wilderness Area Source: U.S. EPA

39. How do we get to natural visibility? Source: Ames (2001) National Park Service

40. Emissions = Population x Demand x Emissions Rate x Control Efficiency So what will it take to return visibility in the West to natural conditions?

44. Conclusions • Since Denver is now in compliance with federal air standards, is our health protected? • Ozone attainment is borderline • PM2.5 health effects may occur below the standard – no clear threshold • Why can we still see the Brown Cloud? • Fine particles haven’t been aggressively controlled • Are pollutants that affect visibility in the national parks the same ones that affect health in urban areas? • Fine particles degrade visibility and cause health effects • Is visibility in national parks and wilderness areas in the West improving or getting worse? • No strong trends. Overall in the West, clearest days are getting clearer, no change in worst days.

45. What do you think? • Should we go further to improve air quality in the Front Range? • How far should we go to restore visibility in scenic areas to natural conditions?