Monitoring indoor air quality in workspaces is a key part of an employer’s responsibility to protecting the health and wellbeing of their employees.
This guide is for facilities management professionals seeking to install or improve their air quality monitoring system. It’s also for systems integrators and software providers looking to partner with an indoor air quality smart sensor manufacturer.
Here, we’ll explore what factors contribute to good — or poor — air quality, and explain the role of smart sensors in helping to maintain optimum indoor conditions to protect occupants’ health.
Contents
- What is indoor air quality monitoring?
- Why is indoor air quality so important in the workplace?
- What causes indoor air pollution in workplaces?
- What are the most common indoor air pollutants?
- Monitoring all aspects of air quality with a single multi-sensor
- Case study: Cavendish Engineers
What is indoor air quality monitoring?
The term ‘indoor air quality monitoring’ refers to the process of gathering continuous, real-time data on the particles, gases and chemicals present in the air within a building.
Collecting and analysing this data can help you identify trends and problem areas, making adjustments or automating processes accordingly.
It’s important to differentiate between indoor air and outdoor air, as some concentrations of organic chemicals can be higher inside. In fact, according to the Environmental Protection Agency (EPA), the level of indoor pollutants is usually two to five times higher than that of outdoor levels. In some cases, indoor pollutants can be 100 times more damaging than outdoor equivalents.
Many companies also place a high focus on good ventilation — especially in the light of Covid-19. While this is clearly important, sometimes this can introduce contaminated air into a building. Monitoring can help you find the right balance.
Why is indoor air quality so important in the workplace?
The health of a building can directly impact the health of its occupants. Having good indoor air quality is key for reducing the risk of airborne disease and detecting things like mould growth.
Indoor air quality can not only affect health, comfort and wellbeing, it can also have a direct impact on productivity. Poor air quality could even lead to prolonged illnesses leading to extended or increased absences. Indeed, poor air quality results in a loss of productivity estimated to be worth tens of billions of pounds worldwide.
So monitoring is important not just for reasons of responsibility. It makes good business sense, too.
Read our insight ‘How sensors can help keep staff safe and well’.
Why indoor air quality matters
Create consistent air exchange Proper air exchange can dispel odours, chemicals, volatile organic compounds (VOCs), particulate matter (PM) and carbon dioxide (CO2), also reducing disease transmission. | Keep occupants safer Monitoring air quality can reduce the spread of pathogens and ensure healthy air flow. |
Ensure cleaner air Remove harmful particles and automate HVAC systems. | Gain better humidity control The right humidity levels can also improve health and boost productivity. |
What causes indoor air pollution in workplaces?
Indoor air quality can’t be defined as a simple concept or equation. Rather, it’s a constantly changing interaction of complex factors which can affect the types, levels and impacts of pollutants in the air.
These include:
- Sources of pollutants or odours
- Design, maintenance and operation of HVAC systems
- Moisture and humidity levels
- Occupant susceptibilities
Common indoor air pollutants
Workspace environments can vary significantly and can depend on things like the age of the building and construction practices. However, there are some commonalities in terms of indoor air quality issues, with many of the pollutants the same regardless of other factors.
Carbon dioxide (CO2)
Monitoring CO2 levels is an important part of striving for overall optimum air quality. A CO2 sensor measures the concentration of particles in the air at parts per million (ppm). Between 400-1000 ppm is a concentration which demonstrates good air exchange. 1000-2000 ppm can lead to complaints of drowsiness. And 2000-5000ppm can lead to a number of problem issues, including headaches, sleepiness, poor concentration, increased heart rate and nausea.
One way to reduce CO2 levels in a room is to add a few plants — they’ll boost the oxygen levels in the air, too.
How to monitor CO2 levels
A non-dispersive infrared (NDIR) sensor uses specific wavelengths of light to measure the amount of CO2 in the air. As air enters the sensor, a light set at one of the specific wavelengths for CO2 — usually around four microns — is activated at one end of the sensor. The other end holds a receptacle to measure how much light makes it to the other side. Once the light is activated, CO2 gas molecules absorb the specific band of infrared light. The amount of light it absorbs depends on how much carbon dioxide is present. The more CO2 present, the more light the sensor will absorb.
Volatile Organic Compounds (VOCs)
VOCs aren’t one specific substance, but rather a group of compounds emitted as gases into the air from products and processes. Things like paints, solvents, aerosols, pesticides, air fresheners, adhesives, cleaning products and disinfectants all produce VOCs. Office printers and copiers can be other sources of VOCs in buildings, and they are present in some printing materials like inks.
They’re also emitted from new furniture and carpets in a process known as ‘off-gassing’. Which means that, while it’s tempting to think of old buildings as being the worst culprits for air quality, new or newly renovated buildings can actually have higher levels of VOCs.
VOCs can also enter a building via polluted outdoor air.
Common examples of VOCs include:
- Benzine, emitted from petroleum
- Formaldehyde, common in many fabrics, coatings and building materials
- Acetone, found wallpaper
- Ethanol, found in paints
- Butanone, found in paints and other coatings, glues and cleaning products
- Ethylene glycol, used in industrial solvents, paints and detergents
- Methylene chloride, used for paint strippers, degreasing, cleaning and manufacturing
Detrimental effects on health can include headaches, dizziness, nausea and coughing. Other symptoms are things like eye, nose and throat irritation, fatigue and allergic skin reactions. Long-term exposure has even been related to liver and kidney damage, as well as cancer.
How to monitor VOC levels:
The best way to monitor VOCs is to establish a baseline measurement to find average levels, and then look for changes.
You can do this using a sensor with a VOC index. It measures VOC levels over a 24-hour period, calculates the average value and assigns it ‘VOC Index 100’. Once the average is calibrated, the sensor can then monitor for changes. Values are measured on a range of 0-500. Values between 100 and 500 indicate deterioration, while values between 0-100 suggest improvements in air quality.
For more on VOCs read our insight here
Particulate matter (PM)
Particulate matter is found in the air at any given time. But high concentration of these particles can lead to poor indoor air quality, resulting in health issues or exacerbating existing conditions.
Particulate matter is a complex mixture of solid and liquid particles suspended in the air. These can include carbon, complex organic chemicals, sulphate, nitrates, ammonium, sodium chloride, mineral dust, water, and a series of metals.
In fact, there are particles of organic and inorganic matter, such as dust, pollen, or smoke, suspended in the air all the time. They come from different sources: primary and secondary.
Primary sources include things like road transport and fuels burned for industrial, commercial or domestic purposes. Secondary sources are formed in the atmosphere from chemical reactions of gases such as nitrogen oxides and volatile organic compounds.
Particulate matter is categorised by particle size, with three classifications:
- Ultra fine: <0.1µm in diameter
- Fine: 0.1 to 2.5µm in diameter
- Coarse: between 10µm and 2.5µm in diameter
Coarse particles settle relatively quickly whereas fine and ultra-fine particles remain in suspension for longer. Sometimes called PM10 particles, coarse particles are small enough to be inhaled and enter the lungs. These include dust, pollen and mould spores.
PM2.5 particles (fine and ultra fine) are so small they can get deep into the lining of the lungs and even enter the bloodstream. These include combustion particles, organic compounds and metals. Generally, PM2.5 and lower are considered more hazardous to humans.
How to monitor particulate matter:
Indoor air quality sensors use advanced technology to detect all PM levels in real time. They provide continuous measurements of particle concentrations, producing valuable data and insights and enabling trends to be tracked. If PM reaches a certain level, ventilation can be automated or an alert triggered to open a window.
For more information, read our PM insight.
Moisture and humidity
Controlling moisture and relative humidity in occupied spaces is another highly effective way of improving air quality and protecting occupants’ health. In fact, scientists at Yale University have proven that humidity levels play a key role in how easily viruses like flu and Covid-19 can circulate. Their research has shown that humidity levels of between 40-60% are ideal for slowing the transmission of viruses. With this level of moisture in the air, any germs that are expelled in a cough or a sneeze tend to fall quickly to the floor, whereas in drier conditions the germs hang around in the air for a lot longer – sometimes many hours – making it easier for others to then breathe them in.
Relative humidity levels that are too high can contribute to the growth and spread of unhealthy biological pollutants, as can failure to dry water-damaged materials promptly or to properly maintain equipment like humidifiers, refrigerators and ventilation.
Humidity levels that are too low, however, may contribute to irritated mucous membranes, dry eyes and sinus discomfort.
How to monitor humidity levels:
A good air quality sensor can effectively monitor humidity levels. The sensor data can be sent to cloud software, to display the real-time data, or directly to a building management system to automate heating, ventilation and air conditioning.
For more information; read our insight ‘Why humidity levels are key to keeping your office healthy’.
Temperature
The right ambient temperature in a workspace is important. Too hot and people can feel dizzy and even faint. It can also exacerbate some conditions, like high blood pressure. Too cold and occupants can be uncomfortable and unproductive.
There isn’t one specific ‘right’ temperature, as comfortable levels can depend on the type of work done at an organisation. Sedentary office workers may need a higher temperature, for example, than active factory workers. In general, comfortable conditions tend to fall between 16-24oC.
How to monitor temperature:
A temperature sensor can measure ambient conditions within a room or a zone, triggering an alert if the temperature changes by more than 0.5oC.
Monitoring all aspects of air quality with a single multi-sensor
Looking at the sheer number of factors which can impact air quality, it can seem a lot to take in and a daunting task to keep track of everything. However, you could choose a multi-sensing device which contains integrated sensors for temperature, relative humidity, CO2, PM, and VOCs.
This allows organisations to benchmark and monitor all of these levels, developing ventilation and filtration strategies and setting parameters to automate HVAC systems.
Find out more about indoor air quality multi-sensors
Cavendish Engineers: introducing a more efficient approach to building controls with Pressac’s CO2 sensors
Background
Cavendish Engineers are experts in the built environment. With over 20 years in the industry, they’re known for their innovative approach to designing and delivering retrofit solutions.
Their service allows clients to minimise energy consumption, improve performance and efficiency and create more comfortable spaces in which to live and work.
The challenge
Cavendish Engineers were commissioned by their client, a UK market leader in high-end commercial property, to improve the efficiency of workspaces across their London portfolio. The move was driven by their 2020 energy-reduction targets and Energy Savings Opportunity Scheme (ESOS) compliance.
An audit revealed the ventilation system was highly inefficient. It was running across their buildings, at full speed, throughout the working day, with energy being used to supply fresh air regardless of need.
Cavendish Engineers set about designing and developing an intelligent system using real-time workspace data to automate ventilation controls.
The solution
Cavendish found an ideal solution in our CO2 sensors.
By retrofitting a number of sensors on each floor of the building, they could get an accurate measurement of CO2 levels throughout the day, then control the air handling units based on demand.
Rather than running at full speed all day, units respond to increases in CO2 levels as occupancy increases. As well as preventing the building from wasting large amounts of energy, the technology also gives facility management teams full, 24/7 visibility of workspace conditions.
The results
The project delivered a 42% reduction in air handling, and has been shortlisted in the CIBSE Building Performance Awards 2018.
Cavendish Engineering have since developed and installed their intelligent system, now known as C-Tech, in offices of numerous blue-chip companies across London. They’ve also expanded the system to encompass our temperature sensors, which deliver intelligent heating and cooling driven by real-time demand.
Read the full case study here.
A new approach to air quality monitoring
It’s clear there are a wide number of factors which can impact the indoor air quality of a building. Understanding the importance of monitoring IAQ is a good place to start, before starting to look at the more granular details. Smart sensors, or one smart multi-sensor, can offer in-depth insights into IAQ, establishing acceptable levels before HVAC automation or other intervention kicks in. For businesses, it’s the smart choice. Good indoor air quality can help to keep occupants healthy and well, boosting productivity in the process.
Find out more, talk to us today or visit www.pressac.com.
