Evaluation and Control of Diesel Exhaust (DE):

Transcription

1 Evaluation and Control of Diesel Exhaust (DE): Steps to managing exposure risk Presented by: Paul J. Webb, MPH, MBA, CIH, CSP Colden Corporation Worcester, MA

2 Topics Overview of Diesel Exhaust Diesel Exhaust Health Effects Exposure Assessment Methods Control Methods Steps to Managing Risk IH Assessment of Diesel Exhaust, Colden Corporation 2

3 Diesel Exhaust An old technology Rudolf Diesel Inventor of the compression combustion engine and the fuel that it consumes. Patent received in IH Assessment of Diesel Exhaust, Colden Corporation 3

4 Diesel Exhaust Prevailing Reputation: Diesel is dirty and polluting IH Assessment of Diesel Exhaust, Colden Corporation 4

5 Diesel Fuel Properties Diesel engines do not have an ignition source (no spark plugs) As such, diesel fuel must have a: 1. High flash point 2. Low auto ignition temperature IH Assessment of Diesel Exhaust, Colden Corporation 5

6 Diesel Fuel Properties Chemical and Physical Properties Diesel Gasoline Energy Density (BTU/Gallon) 138, ,000 Flash Point (F ) Ignition Temp. ( F ) Boiling Point (F ) 515 >90 Vapor Pressure (mm HG) 0.40 ~ Flammable Range (%) Specific Gravity (water = 1) IH Assessment of Diesel Exhaust, Colden Corporation 6

7 Diesel Exhaust Components Complex mixture of thousands of chemicals Includes gases, vapors, and fine particles Over 40 air contaminants recognized as respiratory toxins, endocrine disruptors, carcinogens, and reproductive and developmental toxins IH Assessment of Diesel Exhaust, Colden Corporation 7

8 Gas and Vapor Components Oxygen Carbon Dioxide Nitrogen Carbon Monoxide Water vapor Nitrogen Oxides (Nitric Sulfur Compounds Oxide, Nitrogen Dioxide) ) (especially ill Sulfur Oxides) ) Volatile Organic Low molecular weight Compounds Hydrocarbons (Aldehydes) Poly aromatic Hydrocarbons (PAHs) IH Assessment of Diesel Exhaust, Colden Corporation 8 EEI PRESENTATION DIESEL EXHAUST MANAGEMENT

9 Gas and Vapor Components Aldehydes acrolein, benzaldehyde, formaldehyde, acetaldehyde PAH s: anthracene, benzo(a) pyrene, chrysene, phenanthrene, and pyrene IH Assessment of Diesel Exhaust, Colden Corporation 9

10 Particulate Components Elemental carbon (soot) ~20% to 40% adsorbed organic compounds Trace metals, sulfates, and nitrates Nano size particles Most of the harmful compounds account for < 1% total mass and are < 1 micron in diameter IH Assessment of Diesel Exhaust, Colden Corporation 10

11 Particle Components The carbon core is called elemental carbon (EC). When adsorbed organics attach to elemental carbon (EC), the particle is called Organic Carbon (OC). Total Carbon (TC) is the sum of both EC and OC. Elemental Carbon can be sampled using NIOSH method for Elemental Carbon (Diesel Particulate). IH Assessment of Diesel Exhaust, Colden Corporation 11

12 IH Assess Exhaust, C i ment of Diesel Colden Health Effects Diesel Exhaust

13 Health Effects Acute and Chronic Non Cancer Effects Designated Human Carcinogen, IARC Basis of IARC Classification and Discussion EPA Cancer Risk Assessment, 2002 IARC and EPA conclude that DE poses a lung cancer risk to both occupationally exposed groups and the general public. IH Assessment of Diesel Exhaust, Colden Corporation

14 Non Cancer Health Effects Subjective complaints of eye, throat and bronchial irritation Neurophysiological symptoms Headache Lightheadedness Dizziness Nausea Vomiting Tingling and numbness of extremities No reports of reproductive or teratogenic effects IH Assessment of Diesel Exhaust, Colden Corporation 14

15 Non Cancer Health Effects Acute Exposures Associated with increased reports of: Cough, Phlegm, Difficult or labored breathing; shortness of breath (dyspnea) Chest tightness IH Assessment of Diesel Exhaust, Colden Corporation 15

16 Non Cancer Health Effects Chronic Effects Select studies show an increased prevalence of chronic bronchitis Most of the epidemiologic data indicate that there s NOT an excess risk of chronic respiratory disease associated with exposure to DE Evidence is weak to show an association of DE exposure with decreased lung function. Some studies show restrictive disease IH Assessment of Diesel Exhaust, Colden Corporation 16

17 Non Cancer Health Effects Non cancer health effects linked to odor reports More marked effects in smokers More symptoms Larger lung function impairment noticed Non cancer health effects linked to a general irritation mechanism with an underlying inflammation response IH Assessment of Diesel Exhaust, Colden Corporation 17

18 DE Classified as Carcinogen IARC: DIESEL ENGINE EXHAUST CARCINOGENIC Lyon, France, June 12, 2012 After a week long meeting of international experts, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), today classified diesel engine exhaust as carcinogenic to humans (Group 1), based on sufficient evidence that exposure is associated with an increased risk for lung cancer. IH Assessment of Diesel Exhaust, Colden Corporation 18

19 Basis of IARC Decision DE Cancer Risk Study, 2012: 12,315 workers in eight non metal mining facilities Adjustment for smoking and other potential confounders Study estimated diesel exhaust exposure, represented by respirable elemental carbon (REC) Study found statistically significant increasing trends in lung cancer risk with increasing cumulative REC and average REC intensity IH Assessment of Diesel Exhaust, Colden Corporation 19

20 EPA Cancer Risk Assessment, 2002 Epidemiologic studies indicate that workers who were routinely exposed to DE had a 47% greater risk of developing lung cancer than non exposed individuals Difficulties with adjusting for smoking adds uncertainty to the relative risk estimates Studies were based on exposure before current emissions control standards IH Assessment of Diesel Exhaust, Colden Corporation 20

21 Lung Cancer Conclusions (EPA) The epidemiologic studies of exposure to DE and occurrence of lung cancer furnish evidence that is consistent with a causal association. EPA, 2002 IH Assessment of Diesel Exhaust, Colden Corporation 21

22 Cancer Outcomes Mixed Results Ambient Concentrations Early research (1990 s, Dockery, Pope et al.) revealed no statistically significant associations with ambient fine particulates t (PM2.5) and lung cancer incidenceid Occupational Concentrations Concern regarding lung, bladder and lymphatic Lung cancer studied among truck drivers, bus workers, heavy equipment operators, railroad workers, subway workers showing uncertain to slightly l increased risks ik IH Assessment of Diesel Exhaust, Colden Corporation 22

23 Cancer Outcomes Summary It s all about the exposure assessment!! Currently no standard method of measurement. Most of the early studies had poor to non existent exposure assessment. Use of job titles. Studies riddled d with misclassification of exposure (some random misclassification, some not). Confounding by co contaminants t a very important t issue. What to monitor for, what is the best marker?? IH Assessment of Diesel Exhaust, Colden Corporation 23

24 IH Assess Exhaust, C i ment of Diesel Colden Exposure Assessment Diesel Exhaust 24

25 Regulations Exposure Limits Federal OSHA does not currently have one specific Permissible Exposure Limit (PEL) for diesel exhaust (DE). DE constituents continue to be regulated under existing PELs. These limits are inadequate for assessing exposure risk. ik Elemental Carbon still used as a surrogate for DE particulates, but a less important tool for newer model diesel engines IH Assessment of Diesel Exhaust, Colden Corporation 25

26 DE Exposure Parameters Ultrafine Particles Formaldehyde Nitrogen Dioxide Carbon Monoxide IH Assessment of Diesel Exhaust, Colden Corporation 26

27 Ultrafine Particles DE controls have greatly reduced the larger and visible particulate emissions. Smaller particles of less than 2.5 microns are present in DE, are not visibly apparent, and have negligible mass. Diesel engines can exhaust these particles at levels l over 4 times that of background levels Number of particles per volume of air is a more accurate metric than mass per volume (ultrafine particles have little to no mass) IH Assessment of Diesel Exhaust, Colden Corporation 27

28 Ultrafine Particles Real time measurement of particles with diameters from 0.2 to 1.0 microns Non specific, but provides quick reference of relative particle levels at vehicle exhaust relative to clean air Use to screen and prioritize additional IH investigation. Sustained levels >2x clean air should trigger additional IH assessment and DE controls TSI P Trak 8525 IH Assessment of Diesel Exhaust, Colden Corporation 28

29 Formaldehyde Aldehydes are a constituent of DE Formaldehyde is a suspected human carcinogen and a upper respiratory irritant Complaints of eye and nasal irritation most likely result from the aldehyde d component of DE ACGIH 2012 Ceiling Value is 0.3 ppm Formaldehyde serves as a good sentinel of aldehyde exposure IH Assessment of Diesel Exhaust, Colden Corporation 29

30 Formaldehyde Use modified NIOSH Method 2016 for analysis Treated silica sorbent tube Keep samples cool and away from direct sunlight Maximum sampling volume of 15 Liters can be quickly collected by setting a higher flow rate up to 1.5 LPM IH Assessment of Diesel Exhaust, Colden Corporation 30

31 Nitrogen Dioxide Nitric oxide (NO) and nitrogen dioxide (NO2) are components of DE Of the two gases, NO2 has an ACGIH TLV 2012 of 0.2 ppm and is corrosive in very small concentrations Exposure to NO2 can cause eye and nasal irritation, similar to aldehyde exposure NO has a ACGIH TLV of 25 ppm and can also serve as a DE exposure indicator IH Assessment of Diesel Exhaust, Colden Corporation 31

32 Nitrogen Dioxide NO2 sensor range: 0 20 ppm Resolution is 0.1 ppm Nitric Oxide (NO) sensor range: ppm Resolution 1 ppm IH Assessment of Diesel Exhaust, Colden Corporation 32

33 Carbon Monoxide Diesel engines can produce CO but at lower concentrations than gasoline engines Current ACGIH TLV 2012 is 25 ppm Use a Q Trak or other direct reading instrument to sample this contaminant IH Assessment of Diesel Exhaust, Colden Corporation 33

34 Recent DE Assessment Data Garbage truck idling at loading dock: no visible emissions. Area samples were collected at 5 feet from the back of the truck. Results Ultrafine Particles : 35, ,000 p/cc, 4x > outside air Formaldehyde: 0.03 ppm (10% of OEL) Nitrogen Dioxide: 0.8 ppm (400% of OEL) Carbon Monoxide: 2.7 ppm (11% of OEL) IH Assessment of Diesel Exhaust, Colden Corporation 34

35 Assessment Strategy Use ultrafine particle counter to screen for exposure risk If results are >2x background, follow up with formaldehyde, NO2, and CO sampling Local Exhaust Ventilation (LEV) should be required for areas where DE is >2x background IH Assessment of Diesel Exhaust, Colden Corporation 35

36 IH Assess Exhaust, C i ment of Diesel Colden Control Methods Diesel Exhaust 36

37 Regulatory History 1970s EPA regulates diesel emissions from engines used in trucks, buses, and other on road uses EPA reviews and regulates gaseous emissions 1980s EPA regulates particulate emissions 2000 Significant emissions reductions targets by 2007 IH Assessment of Diesel Exhaust, Colden Corporation 37

38 Current Status 2012 For new diesel vehicles, emissions i contaminants have largely been eliminated by the combined improvements in: Diesel fuels Engine design Emissions control technologies IH Assessment of Diesel Exhaust, Colden Corporation 38

39 Current Status 2012 Unfortunately. There remains millions of older vehicles on the road Vehicle maintenance status is highly variable DE varies with engine operating conditions IH Assessment of Diesel Exhaust, Colden Corporation 39

40 Current Control Approach All Diesel Sources Fuel Modification Sulfur Reduction, Biodiesel blends Older Diesel Engines Exhaust Control Devices Particulate filters New Diesel Engines Engine design changes and mandated Emissions Control Technologies IH Assessment of Diesel Exhaust, Colden Corporation 40

41 Diesel Fuel Diesel is a generic term that refers to fuel used to run a diesel engine Diesel fuel can come from petroleum, coal, or bio mass (plant or animal in origin) Diesel fuel is more specifically defined by its ingredients and method of production: Petroleum, Natural Gas, Coal, Biomass Distillation, Esterification, Gas to Liquid IH Assessment of Diesel Exhaust, Colden Corporation 41

42 Diesel Fuel Advantages Diesel vs. Gasoline: Requires less refining Has a higher energy density Diesel engines typically offer 45 to 60% better fuel economy Combustion produces negligible carbon monoxide IH Assessment of Diesel Exhaust, Colden Corporation 42

43 Diesel Fuel Disadvantages Diesel emissions contain several health hazards and if uncontrolled, generate more pollution than gasoline emissions From all transportation sources, EPA estimates that heavy duty trucks and buses account for: 33% of all nitrogen oxide emissions 25% of all particle pollution IH Assessment of Diesel Exhaust, Colden Corporation 43

44 Diesel Fuel Good News EPA regulations have resulted in fuel modification to lower sulfur content since June, 2006* EPA Ultra Low Sulfur Diesel (ULSD) fuel standard in place since June, % Sulfur Content Reduction: 500 ppm to 15 ppm Engine manufacturers are producing engines with lower quantities of harmful emissions Reference: *EPA420 F October 2006 IH Assessment of Diesel Exhaust, Colden Corporation 44

45 Diesel Fuel: Petro diesel Fuel processed from petroleum Petro diesel is obtained in the fractional distillation of crude oil between 200 C and 350 C at atmospheric pressure Ranges from C 10H 22 to C 15H 32 IH Assessment of Diesel Exhaust, Colden Corporation 45

46 Diesel Fuel: Biodiesel Fuel derived from biomass such as vegetable oils and/or animal fats Feedstock (fat source) is primarily rapeseed oil in Europe and soybean oil in the US Biodiesel is commonly defined as a methyl or ethyl ester IH Assessment of Diesel Exhaust, Colden Corporation 46

47 Biodiesel Fats and alcohol yields biodiesel fuel IH Assessment of Diesel Exhaust, Colden Corporation 47

48 Diesel Fuel: Synthetic Diesel derived from a variety of feed stocks including biomass, natural gas, and coal. Biomass to liquid (BTL) Natural Gas to liquid (GTL) Coal to liquid (CTL) A three step Gas to Liquids processing technology is used that reduces sulfur and aromatic carbon content. IH Assessment of Diesel Exhaust, Colden Corporation 48

49 Diesel Particulate Filters Diesel particulate filters (DPFs) routinely reduce particulate matter by more than 90% Required on all newly manufactured on road and off road diesel engines No mandates on the millions of existing engines IH Assessment of Diesel Exhaust, Colden Corporation 49

50 Diesel Particulate Filters This comparison of particulate matter emissions from two nearly identical vehicles shows the effectiveness of diesel particulate filter retrofits. Source: Clean Air Task Force IH Assessment of Diesel Exhaust, Colden Corporation 50

51 IH Assess Exhaust, C i ment of Diesel Colden Managing Risk Diesel Exhaust 51

52 #1 Establish a DE Policy and Protocol Review organization s existing DE policies Establish or revise existing policy if inadequate to control exposures Develop formal DE assessment protocol Sampling Methods Complaint Response Risk Communication IH Assessment of Diesel Exhaust, Colden Corporation 52

53 #2: Identify Diesel Sources Age of diesel engine/vehicle Vehicle change out policy Preventive maintenance protocol Additional DE control actions Filters, Fuel modification IH Assessment of Diesel Exhaust, Colden Corporation 53

54 #3 Evaluate Exposures Screen for ultrafine particles Conduct more detail evaluation for conditions where ultrafine particle levels exceed 2x background levels Collect details of vehicle use, especially idling practices of operators IH Assessment of Diesel Exhaust, Colden Corporation 54

55 #4: Communicate Results Engage all stakeholders in policy development and implementation Share results with participants Enlist vehicle operators and mechanics to develop DE reduction solutions IH Assessment of Diesel Exhaust, Colden Corporation 55

56 Summary Be proactive. Develop DE policy and assessment protocol before there are complaints Engage stakeholders in the process Inventory DE sources and collect exposure data Acknowledge that DE has the potential to be harmful, but demonstrate through specific actions, that your organization is actively managing this risk ik IH Assessment of Diesel Exhaust, Colden Corporation 56

57 Questions? For further information regarding this presentation, health risk assessments, or litigation support, contact: Colden Corporation Occupational and Environmental Health Science Group Shannon Magari, ScD, MS, MPH Paul J. Webb, MPH, MBA, CIH, CSP IH Assessment of Diesel Exhaust, Colden Corporation 57

58 References Program Update: Introduction of Cleaner Burning Diesel Fuel Enables Advanced Pollution Control for Cars, Trucks and Buses. Office of Transportation and Air Quality. EPA420 F October 2006 Silverman, D.T. et al. The Diesel Exhaust in Miners Study: A Nested Case Control Study of Lung Cancer and Diesel Exhaust. J Natl Cancer Inst 2012;104:1 14. Health Assessment Document For Diesel Engine Exhaust. EPA IH Assessment of Diesel Exhaust, Colden Corporation