Ozone, UV and Aerosol studies

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RETROPOLLEN (Reconstructing four decades of spatio - temporal airborne pollen levels for Belgium to assess the health impact)

Andy Delcloo
Royal Meteorological Institute of Belgium
Ringlaan 3
B-1180 Uccle

Contact: Andy Delcloo


General information

Worldwide the burden of allergic respiratory diseases is increasing, enhanced by large-scale air pollution. Anthropogenic emissions affect both the allergens as the allergic subjects by increasing the immune reaction and by intensified biogenic emissions of allergic airborne pollen. In Europe, a quarter of the population suffers from pollinosis. While medical management of allergic rhinitis and asthma is feasible, aeroallergen avoidance is usually the most effective approach to reduce symptoms and pollinosis morbidity. Avoidance can be achieved only if the allergenic pollen exposure can be predicted and if the effects on public health are well understood. Forecasting the spatio-temporal distribution of allergic pollen, however, requires a modelling approach. The transport model SILAM will be applied, since it has recently been set up and designed to operate for Belgium.
The overall objective of RETROPOLLEN is to assess public health effects of birch and grass airborne pollen levels in relation to surface air pollution and climate change using up to four decades of historical observations. This will be accomplished by

- (i) reconstructing the spatio-temporal distributions of birch and grass airborne pollen using SILAM – operating at RMI - ingesting ECMWF’s (European Centre for Medium-Range Weather Forecasts) reanalyzed meteorological datasets and four decades of land-use and land-use change data estimated from the heritage of long time series of vegetation indices derived from satellite remote sensing platforms such as NOAA-AVHRR (GIMMS3g NDVI).
- (ii) compiling and making available historical datasets on airborne allergic pollen observations (from 1982 on, partner Sciensano), medical data on patients suffering from cardiovascular and respiratory diseases including rhinitis and asthma (~500 patient files from 1998 on, Erasme Hospital-ULB, partner; ~750 patient files from 1989 on, Zeepreventorium, partner), mortality rates (from 1987 on), surface air pollution data (from 1990 on, IRCEL-CELINE, partner) collected at regional networks, and ECMWF and RMI in-house meteorological data.
- (iii) evaluating the impact of co-exposure to pollen biogenic particles with anthropogenic air pollutants and meteorological processes on the allergic population health based on statistical health and epidemiology models (from UHasselt, partner).

Ultimately, a robust forecast model for pollen levels and new insights for prevention measures against pollinosis in Belgium are aimed at which could lead to the development of a pollen app for Belgium including new insights in the critical allergy threshold of pollen levels in combination with unfavorable conditions of air pollution and meteorological conditions (allergy risk index).
In short, the baseline of RETROPOLLEN is the use of historical observations carried out and made available by the project partners and datasets that are publicly accessible. These long data series are combined in physical and statistical models that are routinely used by the partners to assess public health effects of allergic airborne pollen levels in relation to surface air pollution and meteorology using mortality data and clinic data on hospitalized patients. Since most data and tools are at the disposal of the consortium, but have never been used before in this specific framework, the feasibility and the chance of success of this project proposal is substantially high


Expected outcome

This targeted and feasible research project RETROPOLLEN is expected to generate multiple scientific and societal outcomes. RETROPOLLEN is based on the analysis and combination of various datasets of long time series of observations collected at the earliest from 1982 on by the partner scientific institutes of the consortium into statistical and mechanistic models routinely used by the partners. The ultimate goal is to provide a framework for an information system (website, app) that alert the general public for possible airborne birch and grass pollen allergy episodes 3-days ahead taking into account the contributions of meteorology, air pollution and climate change. RETROPOLLEN merges the heritage of valuable time series such as the ECMWFs reanalyzed meteorological dataset with contributions of the RMI (i) with pollen observations from Sciensano (ii), time series of surface air pollutions from IRCEL-CELINE (iii), daily mortality data from STATBEL (iv) and clinical patient data on respiratory diseases from the Erasme Hospital (ULB) and the Zeepreventorium (v). Combining these data into the pollen transport model SILAM - operational at RMI – and into statistical models developed by the UHasselt will help to unravel the impact of pollen, weather, air pollution and climate on the public health in Belgium.



The partners within this project are:

  • Sciensano
  • UHasselt
  • Erasme Hospital (ULB)
  • Zeepreventorium