Frequently asked questions about environmental impact categories

As of 7 January 2026, submitting A1 data for environmental declarations in the Dutch Environmental Database became optional; A2 data is mandatory from that date. As of 1 July 2026, EPB calculations in the buildings sector are required to be based on set A2 (EN 15804+A2), in accordance with the amended Environmental Buildings Decree (Bbl) and the Environmental Regulation.

The transition to the A2 set aims to provide a more complete and accurate assessment of the environmental impact of construction projects, in line with the latest scientific insights and European standards. 

Yes, there is a work instruction available to support LCA practitioners in applying set A2 consistently and correctly.

Read more and download the instruction

An environmental impact category describes one specific environmental effect, such as climate change, acidification or eutrophication, expressed in its own unit (for example kg CO2 equivalent or mol H+ equivalent). Because these categories use different units, they cannot be directly compared or added together.

Shadow costs express these environmental effects as a single monetary value per unit of environmental effect, making the different impact categories mutually comparable and allowing them to be combined into a single environmental performance score.

Without this conversion, the individual impact categories would remain separate, without a clear indication of how heavily each effect weighs relative to the others. By applying the weighting set and shadow costs, a single weighted environmental performance score is created, allowing buildings and construction products to be compared in a uniform way.

As of 1 July 2026, the weighting set corresponding to set A2 applies, designated by VRO. This weighting set contains 19 weighting factors, one for each environmental impact category. The full list of weighting factors per impact category is shown in the table on this page.

With the revision of the standard EN 15804 to EN 15804+A2, environmental impact categories have been refined and new indicators have been added, including for toxicity and resource use. For example, climate change has been split into three separate indicators, and categories such as human toxicity and ecotoxicity have been further subdivided. This expansion provides a more detailed and complete representation of environmental effects than the previous set A1.

An environmental impact category describes one specific environmental effect resulting from emissions or resource use during the life cycle of a construction product, such as climate change, acidification or eutrophication. Each category is expressed in its own unit, for example kg CO2 equivalent for climate change or mol H+ equivalent for acidification. Together, the environmental impact categories form the environmental profile of a construction product.

Climate change is expressed in set A2 through four separate indicators: fossil, biobased, land use and land use change, and the total. Climate change (total) is the sum of these three individual indicators. The weighting factor for the total is informative but is not included separately in the ECI calculation to avoid double counting.

Set A1 contains 11 environmental impact categories according to the EN 15804+A1 standard. Set A2 contains 19 environmental impact categories according to the EN 15804+A2 standard. Set A2 introduces new categories and refines existing ones for a more comprehensive environmental impact assessment.

Compared to the old set, the new set now includes sub-indicators and indicators have been added. The main change in this transition is the adjustment of the environmental impact categories of acidification, eutrophication, summer smog, human toxicity and ecotoxicity and subdivision of climate change into three separate categories. 

From 2 September 2024, it was possible in buildings sector calculation tools to calculate with set A2 and the new weighting set alongside set A1. This gave the market the opportunity to gain experience with the new situation ahead of the official entry into force on 1 July 2026.

Since 1 July 2026, EPB calculations in the buildings sector have been mandatory based on set A2 (EN 15804+A2). This change is set out in the amended Buildings and Living Environment Decree (Bbl) and the Living Environment Regulation (Or).

A life cycle assessment or LCA calculates the environmental impact of the building materials and products studied. This results in an environmental profile, which is stored as an environmental declaration in the National Environmental Database. This is done by examining the impact on different environmental impact categories.

Read more about the different environmental impact categories

• The transition has taken place. As of 1 July 2026, EPB calculations in the buildings sector are required to be based on set A2.

• Validated calculation tools have been updated for the new situation.

• A work instruction for compiling LCAs based on set A2 is available, developed by SGS Search on behalf of Stichting NMD.

• Keep an eye out for NMD's communications for updates and guidelines. Follow us on LinkedIn and sign up for the newsletter. 

Stichting NMD has been preparing for the transition to the A2 set for some time, Since 1-1-2021, it has been mandatory to provide both A1 and A2 data. In addition, several projects have been implemented, such as the Accelaration campaign, to update older data. Not all the declarations contain A2 data, because not all category 1 and 2 processes in the NMD processes database contain the A2 set.

The release of the weighting set enabled Stichting NMD to conduct analyses to ensure the quality of the data. This identified several data issues in the A2 data.

No, the results of calculations with the A1 set and the A2 set are not comparable one-to-one because of the differences in methodology and the number of categories. An EPB calculation is therefore performed either with A1 data or with A2 data. It is not possible to combine them.

The transition may lead to changes in the EPB scores of buildings because of the more comprehensive assessment. It is important to understand that a change in score does not necessarily mean a change in actual environmental impact, but is a result of the more detailed assessment methodology. 

Yes. As of 1 July 2026, new and tightened EPB requirements are in effect, recalibrated on the basis of set A2. These requirements apply to offices, and for the first time also to utility buildings such as schools, shops and healthcare facilities.. Check here for the schedule of the changes to the Assessment Method and EPB.

Validated calculation tools have been updated for calculating with set A2 as of 1 July 2026. An up-to-date overview of validated tools and their scope of application is available on the Calculation tools page.Check out the page on calculating tools, our LinkedIn page and our newsletter for updates. 

The NMD will also be enriched with new category 3 C&U environmental declarations that include only the A2 set. In these environmental declarations, which are based on the existing category 3 C&U data, a quality change has also been made. However, this quality change also causes the data in these environmental declarations to change from the current category 3 C&U environmental declarations that served as a starting point.

This data contains the attribute 'A2' in the title, so the user immediately sees that these declarations only contain the A2 set and cannot therefore be used for calculations with the A1 set. No changes will be made to the current category 3 C&U data (which contain only A1 data) and these will remain available for EPB calculations.

A2 data is available in the viewer. The viewer. distinguishes between A1 data (according to EN 15804+A1) and A2 data (according to EN 15804+A2). Not all environmental declarations contain A2 data; this depends on when the data owner submitted the A2 set. For actual calculations with the data, please use the validated calculation tools

 At Stichting NMD, we constantly check the environmental data in the database to ensure that we provide the highest data quality to the public. With the introduction of the A2 set, extensive analyses were conducted. We found that some category 1 & 2 declarations have a relatively high ECI with the A2 set compared to the ECI with the A1 set. 

We contacted the data owners and LCA experts to double-check this data. To prevent abuse and in the interest of transparency, we hereby share the list of declarations with a high A2 ECI. 

Go to the news item to view the list

For more detailed information, visit our dedicated page on calculating with the A2 set. In addition, we will publish regular updates via our newsletterand on this website.