Monitoring indoor air quality for a healthier environment An EU-funded project has made strides to ensure that the energy efficiency of a building’s heating, ventilating and air conditioning need not compromise the health and well-being of people who use the building. Climate Change and Environment © Thinkstock Reducing the amount of cold, fresh air entering a heat exchanger while increasing the amount of re-circulated air is an effective way of cutting energy requirements – however, it can allow the build-up of indoor air pollutants, thereby putting people’s health at risk. The INTASENSE (Integrated air quality sensor for energy efficient environment control) project developed a technology capable of monitoring this risk. ‘Our project sought to integrate micro and nano-sensing technologies into a detection platform which could measure a building’s air quality and identify pollutants,’ explained Project Coordinator, Dr Rob Bell. ‘The goal was to wirelessly link the air quality monitor to an air handling unit in order to manage air quality and ventilation more efficiently.’ INTASENSE has made progress toward its goals in a number of key areas. The team agreed a priority list of indoor air pollutants on which to focus. These key pollutants can be grouped into combustion gases (nitrogen dioxide (NO2), carbon dioxide (CO2), carbon monoxide (CO) and ozone (O3)); volatile organic compounds (VOCs) (benzene, toluene, formaldehyde and p-dichlorobenzene) and particulate matter (PM) (fractions PM2.5 and PM10). In order to detect the combustion gases and VOCs, the team focused on developing conductometric-type sensors and their validation for indoor air quality purposes. Progress was made in two important areas. Firstly, three suitable materials were chosen to detect each gas – tin oxide, nickel oxide and zinc oxide. These were then manufactured on a film just hundreds of nanometres wide or as nanostructures. Secondly, a platform for the sensing material was chosen, made of an aluminium squared chip. Meanwhile, efforts to detect particulate matter centred around developing a non-optical detection module. Progress in this area has seen the project file a patent application with the German Patent Office for a new system design. Research continues and there is a fair prospect of commercialisation in the future. INTASENSE has also developed a fluidic platform which drives and pre-conditions air flow to the sensors while protecting and supporting the sensing devices. Output data from the sensors can be sent wirelessly to a standard computer and displayed using a customised graphical interface. This interface can be used to control pump speed, select sensor types and adjust for specific indoor environmental needs. ‘Development of the complete INTASENSE multifunctional system focused on integrating all of the above research and development outputs into one prototype unit,’ said Dr Bell. Reliability and performance tests have been undertaken to assess the prototype’s functionality. The findings show that the unit is capable of detecting the target gases at specified levels of concentration while wirelessly communicating the results. The flexibility of the system also allows for a number of INTASENSE platforms to work simultaneously, as a network, within a room or a building. ‘The project outcomes will help to provide project partners with opportunities in the air quality and sensor markets,’ added Dr Bell. ‘There’s also a chance for spin-off research – for example, in the UK a project is underway to wirelessly monitor outdoor air quality and link the data with traffic management to alleviate pollution hot-spots in cities caused by traffic.’ Keywords INTASENSE, sensors, indoor air quality, buildings, energy efficiency, air conditioning, ventilation, VOCs, CO2, NO2
