Diesel Particulate Matter and Health Risk: What to do About it? - Karl Bresee, B.Sc., PBD Ecotox, P. Biol. Karen Phillipps, B.Sc., M.Sc., DABT ...
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Diesel Particulate Matter and Health Risk:
What to do About it?
Karl Bresee, B.Sc., PBD Ecotox, P. Biol.
Karen Phillipps, B.Sc., M.Sc., DABT, UKRT, ERT
Intrinsik Corp., Calgary, Alberta
BC BEST Conference, Whistler, BC
May 10, 2018
Problem
Why look at Diesel Exhaust and Particulates
• Sources • Receptors
o Transportation corridors o Air quality concerns in
o Large construction sites urban and rural areas
o Industrial applications o Environmental impact
o Vehicle fleets for mines assessments
(e.g., oil sands or coal) o Protection of human
o Marine traffic health
o Rail traffic
Outline
• What is it?
• Diesel Exhaust (DE) and/or
Diesel Particulate Matter (DPM)
• Overview of Toxicity Studies &
Guidelines
• Examples
1. Measured Data
2. Predicted Data
a) Local
b) Regional Scale
3. Predicted Data Vancouver
• Risk Characterization
• Parting Thoughts
Diesel Emissions vs. Diesel Particulate Matter
• Diesel Particulate Matter (DPM): particles emitted from
diesel engines and equipment from friction (e.g., brakes,
tires)
• Includes particles of many sizes
What is it Made Of?
CO
Coarse Particulate (PM10)
VOCs PM Fine Particulate (PM2.5)
Ultrafine PM (EC)
Ozone
Diesel Exhaust:
A Complex Mixture
NOx PAHs
Semi-
Aldehydes
volatiles
Health Canada Guidelines 2016 • Included a review of health effects data and air quality modelling • New short-term guideline of 10 µg/m3 and long-term guideline of 5 µg/m3 • Both values for ‘diesel exhaust particulate’ • Key studies seem to involve exposure to DE mixtures and older engine technology (pre-2000) • Not clear how values to be used with existing Canadian PM2.5 standards • No surrogates identified for ambient air monitoring
Weight of Toxicological Evidence
• Based on following:
– Epidemiological studies and
potential role of DPM
– Inhalation chamber studies with
humans and animals
– In vitro studies (e.g., cell cultures)
– Endpoints or major adverse effects
weighted as follows:
Causal Suggestive Not likely
relationship of causal causal
relationship relationship
Evaluation of Diesel Exhaust and Health
Endpoint Causality Determination
Acute (Short-term)
Respiratory Effects (e.g., Asthma) Causal Health Canada
Cardiovascular Effects Likely (2016) Weight of
Neurological Effects Suggestive Evidence
Summary For
Chronic (Long-term) Diesel Exhaust
Respiratory Effects (e.g., COPD) Likely
Cardiovascular Effects Suggestive
(a mixture, not just DPM)
Neurological Effects (e.g., allergic Inadequate
inflammation)
Carcinogenicity Causal (lung cancer*)
Inadequate (other)
* Predominantly occupational studies
exposed to DPM and other emissions
Other Regulatory Guidelines for DPM
Agency Value (µg/m3)
Health Canada 10
(acute, 1-hour)
Health Canada 5
(chronic, non-cancer)
California OEHHA 5
(chronic, non-cancer)
California OEHHA 0.03
(chronic, cancer) Unit Risk: 3.0E-04 (µg/m3)-1
US EPA 5 Short-term – none available for comparison to Health
(chronic, non-cancer) Canada
Long-term – non-cancer values are the sameRelating Emissions to Guidelines – Is it Possible?
• Toxicity studies relied upon by Health
Canada and other Agencies involved
older engine technology
• Health Effects Institute (HEI) and US
EPA: data from older diesel engines and
fuels may not be relevant
• Potential for co-exposure to other
compounds in diesel exhaust mixtures
(e.g. NO2, formaldehyde) in key studies
and in the population
• Uncertainty in study designs?
• What monitoring data should be
DPM guidelines – What is the appropriate DE marker? compared (PM, EC, BC)?
• How should DPM be modelled?Data – What should we compare?
• No clearly agreed upon surrogate for DPM or method for
assessing or modelling at this time (e.g. PM / EC / BC)
• National Air Pollutant Surveillance Program (NAPS) –
as of 2017, PM2.5, PM10 and particles in range of PM2.5 to
PM10 are monitored
• Government of Alberta – data available for total
suspended particulate (TSP), PM1, PM2.5, PM10 and particles
in range of PM2.5 to PM10
• British Columbia Ministry of the Environment – data
available for PM2.5 and PM10 Source: Creative Commons (2018)
• Ontario Ministry of the Environment – monitors PM2.5
Elemental Carbon (EC) and Black Carbon (BC) not commonly monitoredExample - Diesel PM International
Europe – has established network for
monitoring of black carbon.
Equivalent Black Carbon (EBC) -
aerosol absorption coefficient is
converted into EBC by correcting the
online measurements with filter-based
EC concentrations determined by
thermo-optical analysis.Example - Diesel PM International
• EBC Measurements can vary with time, sources,
meteorology and other factors
• Correlate with PM
• Does EBC = DPM?
Source: European Environment Agency (2013)Example – PM1 Monitored Data
Jaffre et al. (2014)
• Study of railway diesel PM
emissions in Seattle
• Measured PM1 using 10-
second averages over a 6-
hour period
• Emissions from only 8
trains captured in Figure
Health Canada 1-hour: 10 µg/m3Example – Black Carbon Monitored Data
Health Canada 1-hour:
10 µg/m3 or 10,000 ng/m3
Jeong et al. (2017). Ultrafine and Black Carbon samples from within a morning passenger
commuter train in Greater Toronto Area, 10-car train pulled with diesel locomotive.Examples – Predicted DPM Based on Monitored
Location Sources Annual DPM Average (Range)
μg/m3
Ambient, Boston Urban, industrial (0.8 to 1.7)
Ambient, Washington DC Urban, industrial, 1.4 (1 to 2.2)
(based on EC)
Ambient, South Coast Air Basin, California Urban, industrial, (2.4 to 4.5)
(based on EC) agricultural
Coastal Ambient DPM (predicted, based on EC) Urban, industrial, (0.79 to 1.24)
marine
HC Annual Guideline 5Examples – Predicted Data Local Scale
• Smaller-scale projects, limited sources and range of impact
1-hour (max) μg/m3 Annual (Average)
μg/m3
Project-Specific, Construction equipment: 3.5 0.4
Construction Site, Alberta excavators, articulated
(predicted within 500 m) trucks, tandem and flat
bed rucks, concrete
trucks, water trucks,
pickup trucks, drill rigs,
dozers, crane, logging
truck, graders,
rollers/compactors
Project-specific, Marine traffic - 0.18
(predicted, based on EC)
HC Annual Guidance Values 10 5Example – Predicted Data Regional Scale
Comparison of Predicted Hourly PM 2.5 to Predicted PM Diesel
1000
900 y = 1.348x + 5.0682
800
R² = 0.9751
or
Predicted Hourly PM 2.5 [ug/m3]
700
DPM=0.67x[PM2.5]
600
500
400
300
200
100
0
0 100 200 300 400 500 600 700
Predicted Hourly DPM [ugm3]Example – Predicted Data Regional Scale
Comparison of Predicted Annual PM 2.5 to Predicted PM Diesel
90
80
y = 1.2118x + 1.0987
R² = 0.9873
70
or
Predicted Annual PM2.5 [ug/m3]
60 DPM=0.72x[PM2.5]
50
Comparison of Predicted Annual PM2.5 to
40 Measured (includes forest fires)
6
30
4
y = 0.2434x + 2.2286
20
2 R² = 0.7494
10 0
0 5 10 15
0
0 10 20 30 40 50 60 70 80
Predicted Annual DPM [ug/m3]Example – Predicted DPM Calgary
18
• Predicted hourly diesel
16 particulate matter
• Based on 95th percentile of
Ambient Air Concentration [µg/m3]
14
ambient PM2.5 concentration
12
• Major assumption that
10 conversion factor was 0.68
8 • Modelled vs ambient
depends on contributing
6
sources
4
2
0
2015 2016 2017
Calgary Central 2 Calgary Central Inglewood Calgary NorthWest
Calgary SouthEast GuidelineExample – Predicted DPM Calgary
7
• Predicted annual diesel
6 particulate matter
• Based on annual average of
5 ambient PM2.5 concentration
Ambient Air Concentration [µg/m3]
• Major assumption that
4
conversion factor 0.72
3
• Modelled vs ambient
depends on contributing
2 sources
1
0
2015 2016 2017
Calgary Central 2 Calgary Central Inglewood Calgary NorthWest
Calgary SouthEast Long‐term GuidelineExample – Predicted DPM Vancouver
• Predicted hourly diesel
particulate matter
• Based on 95th percentile of
ambient PM2.5 concentration
• Major assumption that
conversion factor was 0.68Example – Predicted DPM Vancouver
6 • Predicted annual diesel
particulate matter
Ambient Air Concentration [µg/m3]
5 • Based on annual average of
ambient PM2.5 concentration
4
• Major assumption that
conversion factor 0.72
3
2
1
0
2015 2016
Burnaby Kensington Richmond South
Surrey East Long‐term GuidelineExample - Predicted DPM Data Vancouver • Two studies for Metro Vancouver: – Levelton 2007 Air Toxics Emission Inventory and Health Risk Assessment – Sonoma Technology 2015 Toxic Air Pollutants Risk Assessment • Sophisticated methods used to differentiate the contribution of wood smoke PM and diesel PM • Determined 82% of EC was DPM and estimated DPM ranged from 0.56 to 1.0 μg/m3, which are below Health Canada non-carcinogenic limits. • DPM was the dominant contributor to the cancer risk, which was estimated to be 24 per 100,000 based on CalEPA limit and concentration of 0.79 μg/m3. • Dose-response uncertainty was a larger contributor to uncertainty in the final cancer risk estimate than the concentration uncertainty.
Risk Characterization – Short Term Exposure • Health Canada (2016) selected the common LOAEL of 100 µg/m³ as the point of departure, which was based on: – 6 human inhalation studies with healthy and mild asthmatics – Applied an uncertainty factor of 10 (100.5 × 100.5) • Characterization of short-term risk is hindered with uncertainty surrounding exposure and toxicity. • Potential for co-exposure to other compounds in diesel exhaust mixtures not accounted for (e.g. NO2, formaldehyde, PAHs). • Measured ambient PM2.5 concentrations meet CCME 24-hour CAAQS (i.e., 27 μg/m3).
Risk Characterization – Long Term Exposure • Limit based on two key studies: Ishinishi et al. (1986, 1988). • Health Canada (2016) selected the highest reported NOAEL of 460 µg/m³ as the point of departure, which was adjusted: – Dosimetry model to adjust to human equivalent of 120µg/m³ – Applied an uncertainty factor of 25 (100.4 × 10) • Adverse respiratory effects are predicted to range from 330 to 4,400 µg/m³ in humans (US EPA 2003). • Measured ambient PM2.5 concentrations meet CCME annual CAAQS (i.e., 8.8 μg/m3).
Parting Thoughts • Exposure to diesel exhaust and DPM have been associated with adverse health effects (i.e., based on epidemiological and inhalation chamber studies). • Health Canada and other agencies have developed guidelines BUT it is not clear what ambient or modelled data should be compared to these air quality guidelines. • Measured and predicted data vary with methods used and diesel source type. • Currently, certain projects not required to assess DPM like infrastructure projects (e.g., large interchanges or other transportation projects) but industrial applications are (e.g., oil sands mine or SAGD). • Also construction emissions/activities in environmental assessments are requested to assess DPM.
Acknowledgements
Karen Phillipps, M.Sc.,
DABT, ERT, Intrinsik
Bart Koppe, B.Sc., PBD,
P.Biol, Intrinsik
Created by K. Phillipps, Intrinsik with:
Health Canada (2016), WordClouds (2018)References • Environment and Climate Change Canada. 2018. 1990-2016. Air Pollutant Emission Inventory Report. ISSN: 2369-940X. Available at: https://www.canada.ca/content/dam/eccc/images/apei/apei-2018-en.pdf • European Environment Agency. 2013. Status of Black Carbon Monitoring in Ambient Air in Europe. EEA Technical Report. No 18/2013. Available at: https://www.eea.europa.eu/publications/status-of-black-carbon-monitoring/file • European Environment Agency. 2017. Emissions of Air Pollutants from Transport. Available at: https://www.eea.europa.eu/data-and-maps/indicators/transport-emissions-of-air- pollutants-8/transport-emissions-of-air-pollutants-5 • Creative Commons. 2018. Available at: https://creativecommons.org • Health Canada. 2016. Human Health Risk Assessment for Diesel Exhaust. Fuels Assessment Section, Water and Air Quality Bureau, Healthy Environments and Consumer Safety Branch, Health Canada. March 2016. Cat: H129-60/2016E-PDF, ISBN: 978-0-660-04555-9. • Ishinishi, N., Kuwabara, N., Nagase, S., Suzuki, T., Ishiwata, S., and Kohno, T. 1986. Long-term inhalation studies on effects of exhaust from heavy and light duty diesel engines on F344 rats. In: Ishinishi N; Koizumi A; McClellan RO; Stober W (eds.). Carcinogenic and mutagenic effects of diesel engine exhaust: proceedings of the international satellite symposium on toxicological effects of emissions from diesel engines, July, Tsukuba Science City, Japan. Elsevier Science Publishers BV, Amsterdam, Netherlands. pp. 329–348. Cited in: Health Canada 2016. • Ishinishi, N., Kuwabara, N., Takaki, Y., Nagase, S., Suzuki, T., Nakajima, T., Maejima, K., Kato, A. and Nakamura, M. 1988. Long-term inhalation experiments on diesel exhaust. In: Diesel exhaust and health risk: results of the HERP studies. Research Committee for Health Effects Research Programme Studies, Automobile Research Institute, Inc., Tsukuba, Ibaraki, Japan. pp. 11–84. Cited in: Health Canada 2016. • Jaffre, D.A., Hof, G., Malashanka, S., Putz, J. Thayer, J., Fry, J.L., Ayres, B., and J. R. Pierce. 2014. Diesel particulate matter emission factors and air quality implications from in- service rail in Washington State, USA. Atmos Pollut 5: 344-351. • Jeong, C.H., Traub, A., and G.J. Evans. 2017. Exposure to ultrafine particles and black carbon in diesel-powered commuter trains. Atmos Environ 155: 46-52. • Health Canada. 2016.. Human Health Risk Assessment for Diesel Exhaust. ISBN: 978-0-660-04555-9 • HEI (Health Effects Institute). 2018. Diesel Exhaust. Available at: https://www.healtheffects.org/air-pollution/diesel-exhaust • NIOSH (National Institute for Occupational Safety and Health). 2011. Diesel Aerosols and Gases in Underground Mines: Guide to Exposure Assessment and Control. Report of Investigations RI 9687. • US EPA (United States Environmental Protection Agency). 2002. Health Assessment for Diesel Engine Exhaust. National Center for Environmental Assessment, Washington DC. EPA/600/8-90/057F. May 2002. • US EPA. 2003. Integrated Risk Information System Chemical Assessment Summary Diesel engine exhaust; CASRN N.A. National Centre for Environmental Assessment-RTP Office, Office of Research and Development, US Environmental Protection Agency. Available at: https://cfpub.epa.gov/ncea/iris/iris_documents/documents/subst/0642_summary.pdf • US EPA (United States Environmental Protection Agency). 2016. Particulate Matter (PM) Basics. Available at: https://www.epa.gov/pm-pollution/particulate-matter-pm-basics#PM • US OSHA (United States Occupational Safety and Health Administration). 2013. Hazard Alert – Diesel Exhaust/Diesel Particulate Matter. Available at: https://www.osha.gov/dts/hazardalerts/diesel_exhaust_hazard_alert.html • WordClouds by Zygomatic. Available at: https://www.wordclouds.com/
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