Contribution of secondary inorganic aerosols to PM10 and PM2.5 in the Netherlands; measurements and modelling results
Emissions of sulphur dioxide, nitrogen oxides and ammonia are mainly from anthropogenic origin: traffic, energy production and agriculture. It was found that contributions to particulate matter from the conversion of these atmospheric compounds appear 50 per cent larger than were measured and calculated in the past. Consequently, the currently policy measures could be more effective to lower particulate matter levels than was initially projected.
More particulate matter from sulphur dioxide, nitrogen oxides and ammonia than previously assumed
Contribution especially large at high particulate matter concentrations
The average contribution to particulate matter (PM) concentrations was about 30 to 40 percent. When PM concentration levels reach beyond 30 μg/m3, there is an extra increase in the contribution of particulate matter from nitrogen oxides and ammonia. The contribution rose to 50 percent or more. Emission reductions of nitrogen oxides (traffic) and ammonia (agriculture) in the Netherlands and Europe are therefore effective to reduce high PM levels.
Downward trend in line with emissions
For the period 1994 to 2007 PM concentrations, which derive from sulphur dioxide, nitrogen oxides and ammonia, decreased. However, from 2001 onwards, the trends weakened which appears to be in line with the changing emissions of sulphur dioxide, nitrogen oxides and ammonia in Europe.
The report improved the existing knowledge on particles which derive from sulphur dioxide, nitrogen oxides and ammonia, and its contribution to PM10 and PM2.5. The contribution climatology and variability in time and space is treated in relation to PM standards. Special attention was given to the urban increment and modeling performance.
The study was carried out by the ECN as part of the Netherlands Research Program on Particulate Matter (BOP).
More information on Netherlands Research Program on Particulate Matter