Volatile organic compounds

The existing standards for testing gas-phase air cleaners are based on challenging them with gaseous substances. They do not describe air quality measurement using perception, and human emissions (bioeffluents) are not used as challenge pollutants. The present work examines the method that can be used as an alternative or together with other methods used for testing gas-phase air cleaners. The work is a part of the IEA's Annex 78. Three gas-phase air cleaners were tested in the Technical University of Denmark labs.

Metal Oxide Semiconductor (MOS) sensors measuring Volatile Organic Compounds (VOC) seem to be an obvious step towards broadly available Demand Controlled Ventilation (DCV). The previous research shows that MOS VOC sensors can detect high pollution events such as cleaning, painting, or high occupation density. These abilities seem to make MOS VOC sensors suitable to complement ventilation control systems, especially concerning residential ventilation.

Most current building materials are industrially processed, resulting in increased carbon emissions. Global annual carbon emissions due to construction materials reached its peak in 2013, 9.5 gigatons of CO2 were produced. Upcoming circular economies can have a positive impact on the environment since reusing materials can lower carbon emissions. This economy encourages the use of more innovative materials (e.g., textile insulation, cellulose insulation, hemp, and cork) and recycling old materials.

This study introduced a pre-assessment and control tool for indoor air quality (PACT-IAQ) which aimed at multiple pollutant concentrations simulations, pollutant loads estimations and decoration design scheme optimization. Multiple emission sources, sinks, ventilation, pollutant dissemination, and the combined effects of temperature and humidity on material emissions were considered in the tool. Two versions, namely the single zone and multi-zone models, were included in the tool.

HVAC systems in newly built or extensively renovated dwellings were all developed with the aim for energy saving with equal or better comfort. However, these systems (floor heating and DCV systems) have certain characteristics which increase the emissions of Volatile Organic Compounds (VOCs) and give VOCs the chance to accumulate to higher concentrations. This interaction is investigated based on dynamic simulations using a temperature and humidity dependent VOC emission model. 

Since the turn of the century, alarming data produced by the Indoor Air Quality Observatory (OQAI) have led to changes in French legislation, including, most notably, the introduction of compulsory labelling for construction products (decree no. 2011-321 of 23 March 2011).

The ClimACT project has been developed under the priority axis “Low Carbon Economy” of the Interreg SUDOE program. It aims to support the transition to a low carbon economy in schools. Environmental audits addressing energy and water consumptions, waste management, travels to school, procurements and green spaces have been carried out in 38 pilots schools of Portugal, Spain, France and Gibraltar. Indoor air quality and ventilation measurements were also achieved. The concentrations of 9 aldehydes and 10 selected VOCs were measured from passive sampling in two classrooms of each school.

The polyurethane foam industry is projected to reach a worldwide value of up to $74bn by 2022 and with airtightness of new and retrofitted properties continually increasing, an important question arises: what is the impact of these materials on the indoor air quality (IAQ), occupants’ health and indoor environment?

Many studies about photocatalytic oxidation (PCO) have been carried out in laboratories. They use an inert test chamber with ideal indoor conditions: a low volume, a controlled temperature and humidity, and a constant injection of one to five specific gases. The principal aim of this study was to implement, in a real test room (TR) of an experimental house, a titanium dioxide (TiO2) layer to quantify its efficiency.

A physically based diffusion model is used to evaluate the sink effect of diffusion-controlled indoor materials and to predict the transient contaminant concentration in indoor air in response to several time-varying contaminant sources. For simplicity, it is assumed that the predominant indoor material is a homogeneous slab, initially free of contaminant, and that the air within the room is well mixed.