Freeways and Secondary Roadways - something old, something new, something borrowed, something green

1. Freeways and Secondary Roadways -something old, something new, something borrowed, something green A discussion for the UC Davis workshop on near roadway impacts and mitigation, January 24, 2007 Thomas A. Cahill Physics Department and the DELTA Group, University of California, Davis with the Breathe Calif./SET Health Effects Task Force

2. Why this sudden interest in secondary roadways? • Exacerbation of pre-existing conditions… • Increased population and roadway traffic, especially on secondary roads in residential neighborhoods • Difficulty of present roadway models to predict near-roadway transport of pollutants in non-ideal conditions • Difficulty of traffic models to reflect accurately actual roadway pollutant emissions • New dataon • Health impacts – • near freeway epidemiological studies • very fine and ultra fine particle studies • Emissions – car exhaust/diesel lube oil • Transport – very fine and ultra fine particles, and • Mitigation – somethings old, somethings new

3. Study shows how ultrafine particles in air pollution may cause heart disease By Rachel Champeau| 1/17/2008 1:00:00 PM Patients prone to heart disease may one day be told by physicians to avoid not only fatty foods and smoking but air pollution too. A new academic study led by UCLA researchers has revealed that the smallest particles from vehicle emissions may be the most damaging components of air pollution in triggering plaque buildup in the arteries, which can lead to heart attack and stroke.The findings appear in the Jan. 17 online edition of the journal Circulation Research. The scientists identified a way in which pollutant particles may promote hardening of the arteries — by inactivating the protective qualities of high density lipoprotein (HDL) cholesterol, known as "good" cholesterol. A multicampus team from UCLA, the University of Southern California, the University of California, Irvine, and Michigan State University contributed to the research, which was led by Dr. Andre Nel, UCLA's chief of nanomedicine. The study was primarily funded by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency (EPA).

4. "It appears that the smallest air pollutant particles, which are the most abundant in an urban environment, are the most toxic," said first author Dr. Jesus Araujo, assistant professor of medicine and director of environmental cardiology at the David Geffen School of Medicine at UCLA. "This is the first study that demonstrates the ability of nano-sized air pollutants to promote atherosclerosis in an animal model." Nanoparticles are the size of a virus or molecule — less than 0.18 micrometers, or about one-thousandth the size of a human hair. The EPA currently regulates fine particles, which are the next size up, at 2.5 micrometers, but doesn't monitor particles in the nano or ultrafine range. These particles are too small to capture in a filter1 , so new technology must be developed to track their contribution to adverse health effects. 1Not so. We have been doing this for the past year in Sacramento 13th and T Street and Watt Avenue, with mass, elements, and GC/MS (PAHs, alkanes, sugars, and fatty acids) in 9 size fractions.

5. I will give three examples of some relevant work we are doing… Example 1. Meshing the extensive 1970s work on freeways and transport with current data • Roadway design has a major impact on downwind transport, • Downwind transport is dispersion driven, and • Urban very fine/ultra fine aerosols are dominated by secondary road emissions, not freeways • For fine, US EPA MOBILE - 2/3 diesel, 1/3 cars • For fine, CA ARB EMFAC 2007 - 1/3 diesel, 2/3 cars Note: Much of the early work is published in the gray literature but not available electronically. I will scan some of this material into the workshop CD.

6. Another example of some relevant work in progress… Example 2. Studies of heavily traveled secondary roads (Watt Avenue, …) in Sacramento • Higher vf/uf impact by 65,000 v/day (1.5% diesel) than by freeway I-5 (170,000 v/day, 10% diesels) – potential reasons…. • Closer spacing to receptors, • Lack of barriers roadway to receptors, • Stop and go traffic • Dirtier diesels ? • Local impact dominated by 3 winter months • Organic matter very fine/ultra fine in size and richer in heavy PAHs that diesel exhaust

7. The last project is of some work on near-roadway mitigation (later talks) Example 3. Mitigation by vegetation – why now? • highly efficient lung capture for particles < 0.1 μm • Used oil from spark emission vehicles higher in PAHs than from diesel vehicles (Fujita et al, DRI) • Major laboratory PAH concentrations in sizes < 0.15 μm • Major near roadway ambient heavy PAH (BaP,..) concentrations < 0.1 μm • Enhanced deposition velocities for particles < 0.1 μm due to increased diffusion – 15 x at 0.02 μm vs. 0.2 μm • Vegetation is an attractive way to get a deposition surface Best mitigation: Get the small fraction (circa < 2%) of gross emitting cars off the road!

8. Example 1. Meshing the extensive 1970s work on freeways and transport with current data • Lead was a unique, conserved, and, we now know, ultra fine tracer of car exhaust • There was a major ARB/CalTrans effort 1972 -1974 to understand lead from Los Angeles freeways • Our component: • 5 LA freeway sites (1 flat, 2 cut, 2 raised section) • 120 transects, each with • 2 hr resolution, day and night, • 5 size modes, • Full elemental analysis > sodium • Line source modeled concentrations

9. Los Angeles CA US Sponsored Links ----Online Offers Will Not Print---- 1973 - at grade 1973 - cut section 1973 fill section Zhu et al 2002

12. Results for the Santa Monica freeway – also used by US EPA for their model

13. Lateral transport from freeways: theory, lead from at grade and from cut (depressed) freeway configurations

14. Lateral transport of ultra fine particles – efficient transport, no coagulation! Wind

15. Lateral transport at grade

16. What was the effect of the two upwind freeways? • Assume 8 km upwind • Assume “sliding box” mixed cell = 4 m • Assume LA inversion = 400 m • Assume no coagulation, settling, etc. • Then = Concentration ~ 1% of freeway peak • Even adding the San Diego freeway,, no more than a few % from freeways. • Actual upwind value circa 15% of near roadway peak • Thus, circa ¾ BC and particle number from non-freeway sources Note: ARB EMFAC ~ 2/3 cars, 1/3 diesels

17. January 6, 2007

18. And more ….Check the distances: < 530 m, <1060 m, 1060 m to 1600 m, > 1600 m

19. Lateral transport – at grade, cut and fill – no trees or barriers Lead 10 g/m3, 24 hr

20. Size and composition of diesel aerosols, including ultra fines (U. Minn./DRI/UC Davis) Roadway studies of diesel and auto emission rates California CERC and Nevada DRI laboratory data HEI Tuscarora PA tunnel study freeway studies CA Air Resources Board studies of freeway ultra fines Breathe California (ex- Amer. Lung Assoc) studies of secondary roadways in Sacramento Toxicity of used diesel and spark emission vehicle Lubricating oils - Nevada Desert Research Inst. EPA Region IX/ASU/UC Davis organics, trucks, trains, and cars New information – vehicular emissions

21. U. Minn. Dynamometer Diesel tests; DRI mass and sulfates, DELTA Group S and elements Fuel Lube oil PM2.5 PM0.25

22. U. Minnesota Dynamometer Diesel Tests; same California fuel, different engine – no mention of smoke Lube oil Average Zn to mass, all DRI tests, 1800  1300

23. New information on the toxicity of car exhaust • There is evidence that spark emission car exhaust has more heavy PAHs than diesel truck/bus exhaust • Theory of PAH formation makes small cylinder vehicles worse than large cylinder vehicles • Temperature of formation for PAHs is low, < 600 C • Higher cylinder wall to volume ratio, cars vs trucks • Gertler at al 2002 had the benzo-a-pyrene emission rates roughly the same per vehicle, cars vs trucks, for the HEI Tuscarora Tunnel Study • We find relatively high ultra fine mass from the lubricating oil in CNG busses, ~ ¼ diesel busses • Eric Fujita at Desert Research Institute showed used spark emission lubrication oil was 10 to 20 times higher in PAHs than used diesel oil

24. Typical daytime traffic 50 m south of sampling site

26. Cars have more PAHs in their oil than diesels

27. Del Paso Manor Arden Middle School Sacramento CDS ARB 13th and T

28. Example #2: Arden Middle School at Watt Avenue – 65,000 v/day, > 98% cars Watt Avenue Arden Middle School Sebastian Way

29. Watt Ave Traffic - 15 m from school: No mitigation by road configuration possible

30. HETF data unexpected fine mass – mis-tuned natural gas water heater – fixed in 30 min! Figure 15 PM2.5 mass and 3 sub components, Arden Middle School site

31. Result – Very fine/ultra fine mass at Arden Middle School Gertler et al 2002 cars and trucks Using Zn ratio from DRI diesels

32. rain rain wind

33. Mass in the finer fractions

34. Comparison of composition: Arden Middle vs. Roseville rail yard

35. Surprise! Vanadium is most likely associated with bunker oil combustion from ships in the port of Oakland.

36. PM2.5 Sac. 13th and T, Jan - Mar, 2007 Winter

37. PM2.5 Del Paso Manor, Jan - Mar, 2007 Winter

38. Even size and time resolved aerosols track across 4 miles of Sacramento (wood smoke)

39. PM2.5 Del Paso Manor, Mar - May, 2007 Spring B Spring A Trestle fire

40. Surprise! Upwind and downwind are essentially equivalent (TMC, ASU in progress)

42. Car exhaust dominates Watt Avenue PAH concentrations Benzo{a}pyrene ~ 1/4

43. Example #3: Mitigation via vegetative capture - theory • Very fine (< 0.25 m) and ultra fine (< 0.1 m) diameter particles have suspected health impacts via several mechanisms including - • Insoluble ultra fine particles in the lung and heart • Carcinogens in the lung • Very fine (< 0.25 m) and ultra fine (< 0.1 m) diameter particles have relatively high removal rates via diffusion if a surface is close • Vegetation can provide such a surface

44. Bottom line: Very fine and ultra fine particles can be preferentially removed by diffusion to surfaces

46. “To separate the effect of the planting from the freeway configuration would be a great mistake” (Cahill et al, ARB 502,1974) • “The embankments of the cut section freeways were heavily planted.” • The Santa Monica cut-section site had “a dense thicket of bushes ~ 20 feet high at the crest of the embankment hard against the right of way fence.” • The Harbor cut section freeway site “ was similarly planted, with eucalyptus and bushed extending higher than 30 feet on the downwind site” • “The thickets were quite dense, and effectively cut the wind in their lee.”

47. UC Davis Mechanical Engineering 20 m wind tunnel

48. Size distribution of flare aerosols – scaled to tunnel wind velocity

49. Test in progress: Erin is watching the readout of wind velocity

50. Mitigation of very fine and ultra fine particles by vegetation (preliminary: ongoing HETF project) Wind velocity (mi/hr)