Beskæftigelsesudvalget 2019-20
BEU Alm.del Bilag 101
Offentligt
Version 2 Diesel exhaust particles 11072019
Short report from Danish Working Environment Authority´s (AT) Occupational exposure
limit quality committee. Evaluation of the report: Diesel exhaust particles: Scientific basis for
setting a health-based occupational exposure limit
Members of the Quality committee: Anne Mette Zenner Boisen (Miljøstyrelsen); Anoop Kumar Sharma
(DTU Fødevareinstituttet) ; Mette Lausten Hansen (Arbejdsmedicin AUH) Jesper Bo Nielsen (Institut for
Sundhedstjenesteforskning SDU); Vivi Schlünssen (NFA)
This report is based on a meeting 8
th
April 2019 at AT where the results from the report were discussed after
the authors presented the content of the report. The members of the quality committee had the chance to ask
questions to the authors.
The Report: Anne Thoustrup Saber, Niels Hadrup, Sarah Søs Poulsen, Nicklas Raun Jacobsen and Ulla
Vogel. Diesel exhaust particles: Scientific basis for setting a health-based occupational exposure limit.
The National Research Centre for the Working Environment (NFA) December 2018. Report available from
www.nfa.dk
 BEU, Alm.del - 2019-20 - Bilag 101: Orientering om NFA’s forslag til grænseværdier for fem kemiske stoffer, fra beskæftigelsesministeren
Version 2 Diesel exhaust particles 11072019
Overall evaluation of the report
The report reviews data relevant to assessing the hazard of diesel exhaust particles (DEPs) in humans and
animals. Furthermore, toxicokinetics and mechanisms of toxicity are reviewed, and core previous risk
assessments of DEPs s are summarized. The scientific basis for setting an occupational exposure limit (OEL)
are presented and based on this, the authors suggest a health based OEL for DEPs.
In general, the report is well written with a clear structure and easy to follow. A table describing key
characteristic for the three studies included in the meta-analysis used for risk assessment could have been
helpful.
The committee judge the included literature in general to be sufficient and covering. The literature search
was performed by a research librarian, and we recommend including details of searched databases and the
search strings including dates for covering of the search as an appendix in the report.
DEE consists of gases (VOC, COx, NOx) and particles with a large surface area and can be regarded as a
process-generated nanomaterial. Often elemental carbon are used as measure of DEP, and the authors regard
this as the best marker of DEP. There is sufficient evidence of carcinogenicity of DEE, DEP, and DEP
extracts in experimental animals, as well as sufficient evidence that DEE is carcinogenic to humans and
causes lung cancer, and DEE is classified as a group 1 carcinogen by IARC (IARC 2014). There is very
limited evidence from DEE emitted from “new technology” diesel engines and the DEP concentrations in the
performed chronic inhalations studies with new technology engines in rats and mice were likely too low to
induce detectable levels of cancer.
The authors chose to focus on studies dealing with occupational exposure by inhalation, and the committee
supports that decision, as inhalation probably is the major route of exposure for DEP´s.
The authors were able to base the suggested health-based OEL on human data from epidemiological studies,
but they also assessed DEP hazard based on experimental animal studies in order to support the human data.
The committee supports the use of epidemiological data as the best suited data for setting a health based OEL
for DEP, and we will not further evaluate the hazard assessed from animal studies. Of note, data from animal
studies provided considerable higher DEP levels for excess lung cancer risk level compared to the
estimations based on the epidemiological data.
The authors regard inflammation and carcinogenicity as the critical adverse effects, but because both DEP
and NOx induces inflammation the authors abstain from using inflammation and assessed carcinogenicity as
the critical adverse effects which is supported by the committee.
The authors states that both inhalation of DEE and instillation of DEP and DEP extracts is able to induce
mutations in lungs of mice and conclude both primary and secondary genotoxicity of DEP is present, and the
committee supports to consider carcinogenicity as a non-threshold effect.
The authors used estimates from a meta-analysis including 3 original studies in their risk assessment
(Vermeulen et al. 2014b). All three studies had information on dose-response relationship between exposure
to diesel exhaust quantified as elemental carbon and risk of lung cancer (Vermeulen et al. 2014b). All but one
study had information about smoking, and the authors of the meta-analysis justify that smoking does not
confound the result presented in the meta-analysis. All together the three included studies are regarded as
high quality studies with low risk of bias.
 BEU, Alm.del - 2019-20 - Bilag 101: Orientering om NFA’s forslag til grænseværdier for fem kemiske stoffer, fra beskæftigelsesministeren
Version 2 Diesel exhaust particles 11072019
Setting an occupational exposure limit for DEP
The present working group supports the decision to use the epidemiological data to derive OELs
Exposure was measured as elemental carbon in µg/m3-years. The intercept was set at 0, and the slope was
determined to be 0.000982 with a standard error of 0.000219 based on Vermeulen et al 2014b.
The authors use Danish life time risk of developing lung cancer (0-74 years): 4.9% for men and 4.5% for
women.
The quality committee support the author’s recommendation: The expected excess lung cancer risk in
relation to occupational exposure to DEPs is 1:1 000 at 0.45 µg/m3, 1:10 000 at 0.05 µg/m3 and 1:100 000
at 0.005 µg/m3.
Of note the risk estimates allowing 1: 10 000 excess lung cancer cases or less are all close to the current
ambient air concentrations of elemental carbon (0.4 µg/m3 for rural measurements in Denmark (Massling et
al. 2011) and 2.7 µg/m3 on a major street in Copenhagen, Denmark (Palmgren et al. 2003)
References
IARC. Diesel and gasoline engine exhaust and some nitroarenes. IARC Working Group on the Evaluation of
Carcinogenic Risks to Humans. Vol. 105. IARC Monographs on the Evaluation of Carcinogenic Risks to
Humans. Lyon, France: WHO; International Agency for Research to Cancer, 2014.
Massling A, Nøjgaard JK, Ellermann T, Ketzel M, Nordstøm C. Particle project report 2008 - 2010.
Particulate contribution from traffic in Copenhagen. NERI Technical Report, No. 837. Aarhus, DK: National
Environmental Research Institute, Aarhus University, 2011.
Palmgren F, Wåhlin P, Loft S. Luftforurening med partikler i København. En oversigt. Faglig rapport fra
DMU nr. 433. København: Danmarks Miljøundersøgelser, Miljøministeriet, 2003.
Vermeulen R, Silverman DT, Garshick E, Vlaanderen J, Portengen L, Steenland K. Exposure-response
estimates for diesel engine exhaust and lung cancer mortality based on data from three occupational cohorts.
Environ Health Perspect 2014b;122:172-177.