Trial / Demo
In response to an increased need for energy efficiency to meet climate targets, most new or recently retrofitted buildings are becoming more airtight to reduce heat loss. While better insulation can improve energy efficiency, it can also prevent proper indoor air renewal. With the COVID-19 pandemic highlighting the impact of pathogen transmission indoors, Indoor Air Quality (IAQ) has become a major global health concern.
Poor air quality can be the cause of many health problems, and is responsible for an estimated 3.2 million deaths worldwide each year. Given that we spend more than 80% of our time indoors, designing buildings that are healthy and respect the health of their occupants is a key priority.
Indoor air quality can also have a significant impact on productivity, with studies showing that people working in well-ventilated offices with low levels of air pollutants have double the cognitive function of those in offices with average amounts of the same pollutants. Work related absences related to poor air quality cause three million lost working days each year in the UK, thus putting healthy buildings at the forefront of business strategy moving forward.
Several kinds of air pollutants exist, each with their own associated indoor thresholds and health risks. Whilst some of these pollutants may be caused by a building’s occupants, inadequate maintenance or the penetration of outdoor pollutants through the building envelope, some can also come from the building itself.
Carbon dioxide is the most known air pollutant, due to its direct impact on climate change. CO2 is emitted by most living things when they exhale, with the amount emitted depending on the level of activity. This pollutant can be considered a good indicator for indoor air renewal, as when occupants are in a room, the CO2 level will increase. Measuring the CO2 level in a given space enables clear assessment of the efficiency and suitability of any ventilation or aeration systems, alongside air quality.
CO2 levels can also act as a proxy for determining the risk of COVID-19, or other viral transmission. If a room has low CO2 levels, this is a good sign that the room is well-ventilated and the occupants will be exposed to lower viral loads. The recommended indoor threshold for CO2 is below 1000ppm, as any higher can cause headaches, elevated blood pressure, and decreased cognitive ability.
Some building materials and furniture can continuously emit volatile organic compounds (VOCs). VOCs are a large family of carbon-based compounds, such as benzene or formaldehyde, emitted in gaseous form. They can be found in synthetic coatings, adhesives and glues, and in certain finishing products like paints or varnishes. VOCs can also be generated by occupant activity, such as using cooking oil or cleaning products.
The recommended threshold for total VOCs (rather than for each individual VOC) is 1000 μg/m3. Each VOC has its own associated risks, but generally exceeding this threshold can cause eye irritation, breathing difficulties, coughing, or even heart problems. Formaldehyde alone is also a known carcinogen.
Leaks in the building envelope or opening windows to promote air circulation can bring outdoor pollutants indoors. There are three main outdoor pollutants of concern to indoor air quality: particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3). Particulate matter is mostly emitted by combustion processes, for example, through heating, traffic or agriculture. Nitrogen dioxide is also emitted through combustion, whereas ozone is formed from the reaction of nitrogen dioxide with UV light and outdoor VOCs.
Outdoor pollutants have a wide range of health concerns, such as eye irritation, headaches, asthma attacks and even have carcinogenic risks. The recommended threshold for each of these pollutants is as follows:
Mould forms in humid places with low surface temperatures, allowing condensation to form and create a damp environment. Mould spores are naturally present within the air, and once they come into contact with damp surfaces, can grow and multiply. The formation rate increases within poorly ventilated rooms, producing mycotoxins which can impact not only occupant health but also the building and its materials.
There is no recommended threshold for mould, however the health risks incurred from mould toxicity can include headaches, chronic fatigue, wheezing or coughing, and increased severity of asthma attacks.
The most effective way to guarantee a good level of Indoor Air Quality is to address the issue during the building’s initial design or retrofit. There are multiple ways in which building choices can impact indoor air quality:
When indoor air quality is considered in the design stages of a building, it can help to reduce overall costs in the building’s operational phase and limits the need for costly retrofits further down the line. Growing emphasis is now being placed on indoor air quality by voluntary green rating systems such as WELL, BREEAM, LEED, and HQE. But how can designers and engineers best integrate these IAQ assessments into their design workflows?
IES have signed a strategic partnership with Octopus Lab to bring indoor air quality simulation to a wider international audience, by integrating INDALO®, an IAQ simulation solution, into IES’ Virtual Environment (VE) software.
INDALO® was developed by Octopus Lab in 2012, and is powered by the INCA-Indoor© framework, the only validated calculation engine for indoor air chemistry. It can simulate the concentration of over a thousand air pollutants, considering various parameters such as emissions from materials and furniture, ventilation strategy, outdoor pollution, occupancy, and planned activities.
Acting as a plugin into the Virtual Environment, INDALO® enables building designers to make the best possible ventilation and material choices in order to meet indoor air quality objectives (regulatory or certification) in new or renovated buildings. The solution also makes it possible to predict the risks of mould and viral infections and identify the most appropriate ways to limit them.
The INDALO® plugin exports all relevant information from the VE model to INDALO® for the most efficient workflow, with all necessary data provided in the VE via IES’s Navigator technology. Geometry, ventilation flow rates, and occupancy is already simulated by the VE and the results can then be exported. Additional information such as materials’ emissions, filtration and external pollutants’ concentration, can be input via the VE Navigator to complete the required data for the INDALO® calculation.
The integration of INDALO® into IES' Virtual Environment software paves the way for better air quality for as many people as possible.
Looking to find out more about how IES’s Virtual Environment and INDALO can help you make informed decisions on indoor air quality? Watch our session on-demand, or contact our team to find out more.
