Those that will emit high VOCs. Please consider the chemical contents of the materials.

A number of materials can emit volatile organic compounds (VOCs) including paints, glues, building products, consumer products, and new carpets. In addition, furniture and flooring constructed from particle board, chipboard, MDF, etc., can emit formaldehyde, an irritant gas.

In terms of design solutions it is best to choose low VOC emitting substances. There are a number of labelling schemes in Europe that enable the selection of low-emitting materials and a new pan-Europe initiative to establish and apply limits/standards for VOC emissions from building products and materials based on the so-called 'lowest concentration of interest' (LCI) approach - see: https://www.researchgate.net/publication/254097909_Harmonised_Regulation_and_Labelling_of_Product_Emissions__A_New_Initiative_by_the_European_Commission?ev=prf_pub

Generally speaking, control of pollutant sources is a much better approach than relying only on good ventilation.

Article Harmonised Regulation and Labelling of Product Emissions – A...

I wish to confirm you about the just published by JRC report on 'Harmonisation framework for health-based evaluation of indoor emissions from construction products in the European Union based on the Lowest Concentration of Interest approach (EU-LCI)' (ECA report 29). You can download it from the JRC-IHCP's website at: http://ihcp.jrc.ec.europa.eu/our_activities/public-health/indoor_air_quality/eca/jrc-published-harmonisation-framework-health-based-evaluation-emissions.

Indoor air quality in school buildings is affected by outdoor air pollution, interactions between building system/construction techniques, and operation and management practices, including cleaning, maintenance, and ventilation. Paints, glues and other products for didactic purposes are also important sources of indoor pollution. The relevance of the state of the school buildings is also underlined.

The project SINPHONIE (Schools Indoor Pollution and Health – Observatory Network in Europe)-managed by the European Commission’s Directorate-General for Health and Food Safety and the Joint Research Centre - monitored air quality and related exposure among 5 175 schoolchildren in 114 primary schools in 23 European countries ( 2010-2014). The SINPHONIE results confirmed the nature of the pollution sources: Construction and building management: 61% of the schools lacked wall insulation, 42% lacked roof insulation, 25% had air leakages and 7% presented visible mould growth with a certain level of biological contaminants.

Consumer products: 63% of the classrooms had blackboards and 46% contained one or more computer, printer or photocopier; 69% of the furniture in the classrooms was wood based; and a very low percentage of classrooms had been constructed using certified low-emission building materials. These products can increase the level of exposure in the classroom and affect the respiratory health of children and teachers. Many other substances can contaminate the air in school buildings. Dust and fibers can be a big problem. So can fumes from pesticides, paints or cleaning products. And new carpets, tiles, furniture or drapes often release fumes.The following results of the SEARCH project of Regional Environmental Center for Central and Eastern Europe Country, Office Hungary, 2010 (http://www.isprambiente.gov.it/files/progetti/search-results-europe-rec.pdf) indicate the sources of indoor air pollutants in the classroom (Hungary case):Number of children in the classroom >20 Increased level of toluene -Classroom facing the street Increased levels of PM10 and CO2- Classroom floor: wood Increased levels of PM10, benzene, ethylbenzene, toluene, xylenes, total BTEX and formaldehyde - Classroom wall painted with water-resistant paint Increased levels of benzene, toluene, ethylbenzene, xylenes, total BTEX - Classroom wall renewal < 1 year increased levels of ethylbenzene, xylenes, total BTEX- Classroom cleaning int he morning increased levels of xylene and total BTEX and formaldehyde -Cleaning the classroom floor with broom increased level of NO2 -Cleaning the classroom floor with mop increased level of toluene and total BTEX