Effects of Low-Level Air Pollution:
A Study in Europe


ELAPSE Project

ELAPSE (Effects of Low-Level Air Pollution: A Study in Europe) is a Europe-wide collaboration in a research project Mortality and morbidity effects of long-term exposure to low-level PM2.5, Black Carbon, NO2 and O3: an analysis of European cohorts. The Project is funded by Health Effects Institute under the RFA 14-3: Assessing Health Effects of Long-term Exposure to Low Levels of Ambient Air Pollution and runs from mid-2016 to mid-2019.

The Project addresses the issue of health effects at low air pollution levels by performing targeted analyses of all-cause and cause-specific mortality and morbidity endpoints within selected cohorts of the ESCAPE study with detailed individual data (~380,000 subjects) and in seven very large European administrative cohorts (> 35 million subjects). The analysis focuses on the pollutants PM2.5 (fine particles with an aerodynamic diameter of less than 2.5 μm), nitrogen dioxide (NO2), and ozone (O3), but also exploits the rich monitoring data of black carbon (BC) available from the ESCAPE study with high spatial resolution. Exposure assessment characterizes fine-scale intra-urban as well as between-urban air pollution contrasts using novel combinations of land use regression and dispersion models, routine monitoring data, and satellite observations.



Epidemiological cohort studies have consistently found associations between long-term exposure to outdoor air pollution and a range of morbidity and mortality endpoints. Recent evaluations by the World Health Organization and the Global Burden of Disease study have suggested that these associations may be non-linear, and persist at very low concentrations. However, uncertainty about the shape of the concentration-response function exists especially for the low and high ends of the concentration distribution, which is partly related to the scarcity of observations, particularly in the low range. In this study we focus on analyses contributing to knowledge about health effects of spatially resolved air pollution concentrations at low concentrations, defined as less than current EU, EPA, and WHO Limit Values or guidelines for PM2.5, NO2, and O3. Studies have focused especially on PM2.5, but increasingly associations with O3 and NO2 are reported, for NO2 particularly in studies that accounted for its fine spatial scale variation. Very few studies have evaluated long-term morbidity and mortality effects of O3.

Health Effects Institute



The main hypothesis we will investigate is that long-term exposure to low concentrations of outdoor air pollution is related to adverse health effects. We will define ‘low’ using various cut-points defined by current EU, US and WHO limit values, air quality standards and guidelines, respectively. We will specifically test whether the concentration-response functions deviate significantly from linearity at low exposures. We will exploit selected well-characterized cohorts from the ESCAPE study and seven large European administrative cohorts to study health effects of low level air pollution.

The specific objectives are:

To estimate long-term average exposure to PM2.5, NO2, O3 and Black Carbon by developing new hybrid models that combine monitoring data, land use, satellite observations and dispersion models of the pooled ESCAPE cohort and seven large administrative cohorts
To investigate the shape of the relationship between long-term exposure to PM2.5, NO2, Black Carbon and O3 and three broad health effect categories: (a) natural and cause-specific mortality, (b) coronary and cerebrovascular events, and (c) lung cancer incidence – using a number of different methods to characterize the exposure response function (linear, non-linear, threshold)
To investigate variability of the exposure-response function across population and different exposure assessment methods; as well as the impact of different methods for exposure measurement error; the role of co-occurring pollutants, and the effect of indirect approaches for confounder control in administrative cohorts

Study design

We address the health effects at low air pollution levels by performing new analyses within selected cohorts of the ESCAPE study (~485,000 subjects) and in seven very large European administrative cohorts (> 35 million subjects).

By combining well-characterized ESCAPE cohorts and large administrative cohorts in one proposal the strengths and weaknesses of each approach can be adequately addressed. The large administrative cohorts have more statistical power, can efficiently control for area-level confounders, but have fewer possibilities to control for individual-level confounders. The ESCAPE cohorts have detailed information on individual confounders available.

Participating cohorts are:

Cohort Study area Population size
ESCAPE cohorts
CEANS Stockholm county 22,200
DCH Copenhagen 56,500
EPIC-NL Four Dutch cities 40,000
EPIC OXFORD UK wide 55,300
EPIC VARESE Varese 9,900
E3N France wide 53,500
HNR Ruhr area 4,800
HUBRO Oslo 18,100
KORA Augsburg 9,100
VHM&PP Vorarlberg region 185,300
DNC Denmark wide 28,700
Administrative cohorts
Belgian National 10,000,000
Danish National 5,600,000
Dutch National 7,200,000
English National 850,000
Norwegian National 2,800,000
Rome Rome 1,300,000
Swiss National 7,600,000
ELAPSE Cohorts

Project partners

Institute for Risk Assessment Sciences (IRAS)
Utrecht University, The Netherlands

(coordinating center)
Bert Brunekreef
Gerard Hoek
Maciek Strak
Marjan Tewis
Jie Chen
Aarhus University
Ole Hertel
Carsten Bøcker Pedersen
Torben Sigsgaard
Matthias Ketzel
Danish Cancer Society
Copenhagen, Denmark
Ole Raaschou-Nielsen
Ulla Arthur Hvidtfeldt
Department of Epidemiology, Lazio Regional Health Service
Rome, Italy
Francesco Forastiere
Giulia Cesaroni
Massimo Stafoggia
Matteo Renzi
Heinrich Heine University Düsseldorf
Barbara Hoffmann
Frauke Hennig
Helmholtz Zentrum München
Annette Peters
Kathrin Wolf
Josef Cyrys
Imperial College
London, UK

Fondazione IRCCS - Istituto Nazionale dei Tumori
Milan, Italy
John Gulliver
Daniela Fecht

Vittorio Krogh
Institut National de la Santé et de la Recherche Médicale (INSERM)
Paris, France
Marie-Christine Boutron
Roselyn Gomes
Karolinska Institutet
Stockholm, Sweden
Göran Pershagen
Petter Ljungman
Tom Bellander
Niklas Andersson
National and Kapodistrian University of Athens
Klea Katsouyanni
Evi Samoli
Sophia Rodopoulou
National Institute for Public Health and the Environment (RIVM)
Bilthoven, The Netherlands
Nicole Janssen
Danny Houthuijs
Jochem Klompmaker
Norwegian Institute of Public Health
Oslo, Norway
Per Schwarze
Bente Oftedal
Shilpa Rao-Skirbekk
Scientific Institute of Public Health

Vrije Universiteit Brussel
An Van Nieuwenhuyse
Claire Demoury

Mariska Bauwelinck
Patrick Deboosere
St George's, University of London
Richard Atkinson
Swiss Tropical and Public Health Institute
Basel, Switzerland
Kees de Hoogh
Nino Künzli
Danielle Vienneau
Ulm University
Gabriele Nagel
Gudrun Weinmayr
University of Copenhagen
Zorana Andersen
Jeanette Therming Jørgensen
Shuo Liu
Rina So
Amar Mehta


  • Gerard Hoek, PhD
    Institute for Risk Assessment Sciences (IRAS)
    Utrecht University
  • PO Box 80178
    3508 TD Utrecht
    The Netherlands
  • g.hoek@uu.nl
  • elapse_project