Air Quality

KEMA has decades of experience in air quality modeling of various emitting sources. KEMA-STACKS is the Dutch national model for dispersion calculations

Air pollution can lead to health complaints. Upon construction of new roads and industrial facilities, an increase of traffic intensity or a change in industrial activities, an assessment must be made based on strict standards as determined by governmental authorities.

Using KEMA’s advanced computational model STACKS+, the consequences of all these activities on the air quality can be calculated and presented in an insightful manner.

STACKS+ converts the data on emissions produced by road traffic, industry, shipping and other relevant sources into concentration levels and deposition quantities. STACKS+ is used extensively for:
• calculation of the NO2 and fine particulate concentrations along traffic routes, which are then tested against the thresholds on air quality (including the standards for excessive days and hours)
• calculation of the immission of countless components, including odor, as a consequence of industrial activities (including power plants) relative to the framework established for purposes such as the issuance of environmental permits
• determination of the impact of emission control measures and strategies
• calculation of the quantity of nitrogen deposition in nature reserves as a result of the emissions from road traffic and industry.
 
The STACKS+ model in a nutshell
The STACKS+ model formed the starting point for the Dutch New National Model (NNM) for point and surface sources. STACKS+ goes beyond the NNM framework to include aspects such as calculation of the air quality along traffic routes. STACKS+ is approved by VROM (the Dutch Ministry of Housing, Spatial Planning and the Environment) for use within the application areas of traffic routes and point & surface sources.

STACKS+ is a model based on rational physical and chemical formulas that simulate the situation from hour to hour. The model uses a meteorological database on an hourly basis. Advantages of modeling from hour to hour are:
• The calculated daily and yearly averages can be derived directly from the calculations. This eliminates the need to make (disputable) assumptions, as is often done in screening models by using various empirical relationships.
• Variable emissions figures can be specified, per hour, for point and surface sources.
• The daily flow of road traffic can be taken into account with a high level of detail. This makes it possible to determine the impact of various measures, such as the use of rush hour lanes, traffic jam prevention, introduction of public transport and the implementation of Low Emission Zones in cities.

STACKS+ always makes use of the most recently released VROM specifications for motor vehicle emission factors and background concentration levels of pollutants such as NO2, fine particulates, SO2, ozone and CO.

What can be modeled with STACKS+?
STACKS+ can be used to model the air quality for:
• industrial sources
• industrial sources with high buildings in the near vicinity
• diffuse sources, such as industrial parks or storage and trans-shipment companies
• roads
o highways, secondary roads and local roads
o built up streets in villages and cities (the so-called “street canyons”: roads with buildings on one or both sides that cause the concentrations to rise)
o roads with noise barriers
o tunnel mouths
o parking areas
o bus stations and taxi stands
• shipping
• airports
• cattle farms

The sources listed above can be combined and calculated within one computational session. This makes STACKS+ unique.

How can KEMA assist you in the field of air quality?
KEMA has the necessary expertise, technology and experience to be of service to you for complex projects in the field of air quality. The STACKS+ model offers the flexibility to allow it to be adapted to your specific wishes (including using specific meteorology and emission factors of traffic), and it can handle complex situations that other models are incapable of processing.

For “regular” air-quality calculations, the STACKS+ module included in the Geomilieu software package from DGMR (for the substances NOx, PM10, SO2, benzene, BaP, CO, Pb and –available in mid-2010– also for odor) can be used. Another module within Geomilieu is STACKS D+. STACKS D+ can be used to calculate the nitrogen deposition (NO2 + NH3) along roads.