Several studies have indicated that the presence of aerosols in the ambient air may contribute to serious effects on human health (including increased mortality, hospitalization for respiratory and heart disease, asthma and lung function). For this reason, governments are tightening limits on aerosol concentrations and immissions.
Solid ash and soot particles, emitted from biomass combustion installations, are important sources of aerosols. This is relevant for all biomass combustion systems (both small and large) that are not equipped with effective filtation devices, such as fabric filters. In many areas where biomass combustion systems without efficient particle separation devices are used, aerosol immission limits are strongly exceeded.
With existing technology, the policy aim to increase the contribution of energy from biomass as a renewable energy source may conflict with the aim to reduce aerosol emissions to acceptable levels. Therefore, mitigation of aerosols that result from biomass combustion deserves increased attention from research organizations, manufacturers of boilers and particle removal technologies as well as policy makers.
IEA Bioenergy Task 32 advises to support research and development on reduction of aerosols. Equipment manufacturers need to be encouraged to develop novel, low cost combustion installations and filtration techniques that result in low particulate emissions also in small-scale applications. Task 32 will be instrumental in market introduction of such systems by providing a platform for information exchange.