Health effects of particles from motor engine exhaust and ambient air pollution (HEPMEAP).

A European collaborative project - QLRT-1999-01582

This website is about an European collaborative project called: : Health effects of particles from motor engine exhaust and ambient air pollution (HEPMEAP)" and was launched on May 10, 2001.
Any comments can be send to the co-ordinator Thomas Sandström (see partners). Technical problems can be forwarded to : webmaster @ hepmeap org.


Pictures to illustrate ongoing can be views by clicking in the menu on activities

HEPMEAP project team meeting november 2000 London.
Standing: Flemming Cassee, Luigi Paoletti, Stephan Weiland, Ken Donaldson, Bert Brunekreef, Kees Meliefste, Joanna Brown, Anthony Frew, Frank Kelly and Ian Mudway.
Sitting: Cecilia Gustadisegni , Thomas Sandström, and Susan Wilson


There is increasing concern about the possible adverse effects of ambient particulate matter (PM) on human health and the specific role of traffic exhaust emissions like diesel exhaust (DE). Over the past forty years, the atmospheric concentrations of traditional pollutants, such as black smoke and sulphur dioxide, have declined significantly as the result of clean air legislation. Recent epidemiology data show adverse health effects at lower PM concentrations than had been previously observed and even at concentrations below national ambient air quality standards and health-based guidelines. The specific role of traffic is largely unknown. However, the volume of road traffic has increased substantially, and despite improvements in engine technology the amount of emissions from automobile engines has also increased significantly, especially the amount of particulates released from diesel power engines. This change in the pattern of pollution has been paralleled by a progressive increase in the proportion of children and adults suffering with asthma and other allergic diseases. Evidence from Japan suggests that individuals living close to major highways are more likely to develop allergies, while in vitro studies have shown an adjuvant effect of diesel particulates on the development of specific IgE directed against airborne allergens. Epidemiological studies have also demonstrated a clear association between cardiovascular morbidity, decreased lung function, increased emergency room admissions and airborne concentrations of PM. Human exposure chamber studies have shown that short-term exposure to diesel exhaust has an acute inflammatory effect on normal human airways, with marked neutrophilia, activation of mast cells and the production of cytokines and chemokines relevant to neutrophil accumulation and activation.

Uncertainties about health effect-relevant PM characteristics and components and their respective sources seriously complicate the process of PM health risk assessment and standard setting as well as the application of cost-effective emission and risk control measures. Whether ambient PM with different compositions and contributions of sources will have different biological activity and toxicity remains to be determined: this is of substantial importance, both from the scientific and regulatory point of view.

Despite these uncertainties, recent regulatory decisions have resulted in new and tighter air quality standards (USA) and limit values (EU) for ambient air PM, forcing larger PM emission reductions than formerly anticipated. In addition, the EU air quality objectives for PM10 are stricter than in the USA air quality standards, resulting in the increased need in the EU for PM emission reductions. For ambient PM it is estimated that emissions in cities will need to be reduced to ~ 50% of the present values. The new PM standards will be revised in 2002 (USA) and 2003 (EU) following a critical review of data from new studies on exposure, air quality, emission and source apportionment and PM toxicity and health effects. In particular, in 2003 the EU will also consider whether the PM Daughter Directive should be adjusted or extended e.g. to control for the fine fraction of PM10 (i.e. PM2.5) or to relate to a source related PM fraction like traffic and motor vehicle exhaust emissions.


    Ambient air particles from different parts of Europe and from sites with different traffic exhaust contributions vary in their composition and hence in their biological activity.
    The toxicity of the various ambient (PM10, PM2.5) and experimentally-generated motor vehicle emissions (Diesel, Gasoline) are associated with the chemical composition of the particles, i.e. reactive components and their oxidant and inflammatory potential.
    The adverse biological effects demonstrated by ambient and motor vehicle exhaust PM in in-vitro and in vivo in animal models toxicity testing, relate to epidemiological health effects as well as to the effects shown in humans during controlled experimental chamber exposures.
    Particles generated from different types of diesel and gasoline engines and fuels are not equally potent to induce airway inflammation.
    Gram for gram, particles from gasoline engines are less likely to cause toxicity and health effects than particles from diesel engines.
    Patients from high-risk groups show less protective and more reactive airway responses than those at lower risk.


Last update: 26 May 2001



Nr 1

Collection and characterisation of ambient and engine PM


The objective of this work package is to collect large masses of ambient particulate matter (PM2.5-10, PM2.5) from appropriate sampling sites, together with PM from diesel and gasoline powered engines, and perform physico-chemical characterisation on the samples.

Methodology and study materials

(A) Based on the ISAAC-2 epidemiological studies recently conducted in the Netherlands close to busy freeways, and in German cities sites will be selected with large traffic contrasts, which will ensure maximum contrasts in exposure to traffic related air pollution as can be found in two countries with great traffic densities. Additional criteria will be the nearby presence of large representative schools that were participating in the ISAAC-2 so that epidemiological power is optimal (Four in the Netherlands; high truck traffic/high car traffic high truck traffic/low car traffic low truck traffic/high car traffic low truck traffic/low car traffic and 4 in Munich at four degrees of traffic density ranging from high-traffic city centre to low-traffic suburb). Data generated from the sampled PM that are toxicologically evaluated in WP2-5, are fed back to the epidemiological WP6.

(B) Additional ambient PM samples are collected in Europe to obtain contrasts in sources and composition, specifically from Southern Europe represented by Rome, a tunnel, and rural Scandinavia. Addition of a range of Southern European sites would be of interest, but either demand an extended budget, or reduce the power to perform the planned project. Additionally logistics aspects would delay the launch of the WP´s. Reference samples are obtained in terms of fresh diesel and gasoline engine PM which are sampled from exposure chamber set up. These samples are evaluated in WP2-5 exclusively and composition/source/bioreactivity evaluated in WP 4.

PM2.5-10 and PM2.5 sampling is performed using a high volume (1,100 l/min) low cut-off inertial impactor. The instrument collects large quantities of particles. The instruments efficiently collect well over 100% of the PM mass. 48 ten days samples will be conducted from ISAAC sites, and two each from other sites. PM2.5-10um samples will be collected and analysed separately from PM2.5. We will conduct co-located PM size measurements with Harvard Impactors at all sites to characterise samples. SEM-XRF characterisation is performed on representative samples, whereas a wide chemical characterisation including transition metals, ammonium, chloride, nitrate and sulphate as well as hydrocarbon composition and speciation (giving information on source contribution), are done on all samples.


This work package will deliver a report that describes and motivates (A) the 8 sampling sites to be chosen from the ISAAC-2 locations in Germany and the Netherlands, a second report describing the year-round PM concentrations at these sites. The third report describes the (A) and( B) samples EM and chemical characteristics, which are used for subsequent evaluation in WP4 and 7

Milestones and expected results

The completion of the first report (deliverable) 3 months into the study is the first milestone of this work package. The second milestone is the start of the sampling campaign, 4 months into the study. The 3rd milestone is the completion of the PM report/HV performance report, 20 months into the study. The 4th milestone concerns the additional European and motor engine PM and characteristics, which come gradually through the project.

The expected results are well motivated, sampled and characterised ambient, gasoline and diesel engine PM which are used in subsequent WP.


Partner's activities

Project Progress Report 2001


This project is directed towards an increased understanding of the adverse biomedical effects of ambient and motor engine particles. Furthermore aspects the particles chemical composition as well as size, numbers and other physical characteristics are investigated in relationship to what effects they are causing in the experimental models, as well as European.

More in detail the overall objectives of this research project are:
To assess the inflammatory and toxicological potential of ambient suspended particles (collected at places across Europe with contrasts in traffic intensity) in comparison with diesel and gasoline engine particles.
To relate this to the previously demonstrated effects of exhaust on human airways.
To relate this to the population based epidemiological findings of adverse health effects of ambient particles.
To overall assess toxicity in-vitro and in-vivo in animals and humans, as well as health effects in epidemiological studies in relation to the physico-chemical characteristics of PM.

Results and milestones

Work package 1 (WP1) was directed at collection and characterization of ambient and engine particulate matter (PM). The first milestones were met in motivating sampling sites primarily identified in association to the ISAAC-II-study together with additional sites in Rome, Northern Sweden together with motor engine particle collection. Sampling sites were chosen in locations representative to the pollution levels in the ISAAC-II school yards, as generation of noice and vibrations from the high volume samplers prevented use in these school yards. The second milestone was performance of the sampling campaign. The high volume sampler (HVS) was a highly innovative and cutting edge equipment allowing for large amounts of particles to be collected into different size cuts. This equipment was a cornerstone for the project and an innovative action not previously used in research projects outside the labs of the American manufacturer. The project suffered a major time delay when a number of adjustments had to be performed in order to get the equipment working in European milieu, outdoors and with European wirings. This complementary work was only solved when multidisciplinary resources were organized to solve the problems. Additionally the slits allowing for the particle separations had to be remanufactured. Lastly the equipments were validated against reference low flow pumps, as well confirmation that there was no variability between the tree sampler to be used in the project. Equipments were eventually found to be working properly, even though some aspects as regards sampling efficiency and filter overload, allowed for some changes in durations of the actual particle collections.

Work package II concernes toxicological in-vitro screening of PM. The in-vitro models at King's College London, Napier University, Edinburgh and ISS, Rome were fine-tuned and reference particles introduced. A study of aging of particles was added to the project plan. It was demonstrated that no additional aging took place from the time when the particles arrived to the labs following the collection period and particle extraction work. The stability of data was at three, five and seven months suggests oxidations and other aging actions to occur early. This allows for recovery of some of the time delay as PM do not have to be stored until the annual sampling campaign has been completed.

In Work package III oxidative and inflammatory mechanisms of PM responses in cells and lung fluids is evaluated. The work has been initiated to work in parallel rather than following the in-vitro screening, allowing for an earlier arrival at the milestones.

Work package IV concerns the overall toxicity and PM composition evaluation, which is to be completed following the ongoing screening work.

Work packages V and VI include diesel engine exhaust exposures in human subjects. Asthmatics experienced a significant increase in bronchial hyperresponsiveness 24 hours after the exposure, as compared with filtered air. A complementary study investigated the peak responses to diesel exhaust that were expected at 18 hours after exposure to 100 mg PM10/m3 for two hours vs filtered air. The study based was expanded to comprise healthy subjects, individuals with allergic rhino conjunctivitis and two groups of asthmatics, with and without inhaled corticosteroid treatments. The experience from bronchoalveolar lavage data suggest some airway inflammatory differences between healthy and the other groups. The full set of data from the analyses of the bronchial mucosal tissue biopsies sampled, are therefore expected to be particularly interesting to review.
Local bronchial instillations of PM will be performed following the in-vitro and animal screenings of PM. The planned comparisons between diesel and gasoline PMs is still depending upon ability to secure the substantial findings which are demand for this part of the project.

Work package VII. The final work package is based upon the collection of data from the preceeding WP:s to allow for an increased understanding of what physical and chemical characteristics of ambient and motor engine PM that are related to different effects seen in the experimental and epidemiological studies.

Benefits and Beneficiaries

Novel research equipments have now been established for field use to collect European ambient particles, which in combination with experimental laboratory models is expected to increase the knowledge of how particulate pollution may cause adverse health effects. Additional knowledge has been obtained in how asthmatic respond to diesel exhaust pollution. Beneficiaries may be the general population in Europe, and in particular subjects with pre-existing medical conditions such as asthma, allergy and chronic obstructive pulmonary disease (COPD).

Future actions
The continued sampling campaign, in-vitro animal and human experimental exposure models generates large quantities of data, which will be combined with epidemiological data for an extensive scientific evaluation.

Updated in June 102.

Designed by F.R Cassee