How Do VOC Sensors Work? Everything You Need to Know
How many U.S. citizens live in areas with air quality that could cause serious health damage and shorten lifespans
The answer is about 40%.
Many factors contribute to poor air quality levels, like carbon monoxide, carbon dioxide, mold, mildew, or pollen. The problem is that many don't know the air they're breathing is dangerous, so property owners must know how to run comprehensive indoor air tests.
As you run these tests, one major factor to monitor is the level of volatile organic compounds (VOCs). Unsure what VOCs are and how they affect long-term health? Keep reading to learn more about where they come from, and how you can identify them as you seek to boost your building's indoor air quality.
Introduction to VOCs and VOC Sensors
You'll find traces of VOCs everywhere, as they originate from thousands of sources, both natural and manmade, including:
Cleaning Chemicals and Solvents
Construction Materials
Vehicle Exhaust
Plant Life
Animal Waste, Hair, and Dander
Pesticides
Tobacco Smoke
VOCs are chemicals that emit from these sources in gas form, entering the air. When excessive VOCs are present in the air, it can cause symptoms like nausea, eye or throat irritation, shortness of breath, and trouble focusing. If inhaled for long enough, they can result in serious health effects, such as:
Exacerbated asthma attacks
Heightened Chronic Obstructive Pulmonary Disease
Liver and Kidney damage
Damages to the Nervous System
These gasses also don't break down easily, and stay airborne for a long time, meaning they're hard to eliminate. VOC levels are also often 10x as high in indoor environments as opposed to outdoors, which is a serious issue given Americans spend almost 90% of their time inside.
Clearly, VOCs have to go, but how?
It starts with detection. However, many VOCs are undetectable by the human senses, and won't even evoke symptoms that signify their atmospheric presence.
Thankfully, there's a solution to this conundrum: VOC sensor technologies.
Types of VOC Sensors
There are countless VOCs and each has varying risks to human health. Given the wide variation of VOCs, there are different types of VOC detectors that measure molecules differently.
There are three main types of VOC sensors:
Metal Oxide Semiconductor (MOS): This type uses a basic heating element and a small metal film, and the metal's resistance changes as it runs VOC measurements. The fluctuation in resistance measures the severity of VOC presence. These sensors are low-cost and can detect a wide range of VOCs, althought they only last about 2 years.
Photoionization Detectors (PID): This type uses ultraviolet light to break down chemical compounds and ionize VOCs. Then it measures the ammount of ionization to detect the strength of the VOCs. PID sensors are highly accurate and fast-acting, but also have a limited detection range, are quite expensive, and require routine cleaning and maintenance.
Infrared Optical Sensors (IR): This type measures the ammount of infrared light absorbed by a VOC molecule. Given each type of VOC absorbs a specific ammount of light, IR sensors are great for identifying and measuring individual types of VOCs.
Factors Influencing VOC Sensor Performance
While the sensors all detect VOCs, there are some key differences and risks to note.
For one, environmental conditions can hinder the effectiveness of sensors. So, while MOS sensors are great because they detect a wide range of VOCs, humidity can cause condensation on the sensor, leading to inaccuracies. Likewise, low temperatures can manipulate the heating element, which slows down the response rate and enhances the likelihood of a bad reading. That's why MOS sensors are commonly reserved for indoor use.
On the other hand, PID VOC monitoring devices are extremely effective at picking up low levels of VOCs and aren't as affected by environmental conditions. Given this, they are commonly used in applications like industrial environments, outdoors, and in warehouses.
Humidity can still affect PIR sensors, but the more common problem is can still experience sensor drift, where the output signal changes over time due to wear, dirty sensors, and weather conditions. IR sensors are superior because are less subject to experience.
However, it doesn't matter which type you use, it's imperative to perform routine maintenance and calibration to ensure the sensor reading matches the correct levels of VOC concentration. As a rule, the harsher the environment, the more attendance is required, as calibrating is the only way to guarantee you're getting precise measurements.
Applications of VOC Sensors
At this point, VOC sensors are used across many industries, fields, and environments. Here are a few of the most common uses, and a recommendation on which type of sensor works best.
Environmental Monitoring
VOC analyzers are excellent for tracking outdoor air quality affected by forest fires, excessive exhaust, or industrial pollution. PID sensors tend to be the most effective in these situations, as they are best at analyzing low levels of VOC, given outdoor spaces usually have much lower levels of VOC compared to indoors.
Industrial Safety
Industrial and manufacturing settings can be riddled with harmful compounds like benzene and toluene. These chemicals and corrosive gases can be severely dangerous, and even terminal. As such, it's critical for sensors to be precise and resistant to environmental conditions. Many industrial settings issue legal requirements around VOC monitoring explaining which sensors to use and rules concerning calibration, maintenance, and reporting. However, it's typical to find IR sensors used in industrial areas.
Indoor Air Quality Management
New furniture, cleaning solutions, carpeting, printers, HVAC, kitchen equipment, and even deodorants and perfumes can release VOCs into indoor atmospheres. Especially given indoor spaces trap higher concentrations of VOCs, it's crucial to have a large network of sensors to test for many different VOCs. MOS are very commonly used in these settings, given they are affordable and less subject to environmental conditions.
Take Your Air Quality to the Next Level
Do you know how high the VOC levels are in your building? If not, it's time to find out by implementing VOC sensors to ensure you aren't putting your building occupants at risk.
Prioritizing health and wellness in building infrastructure is now easier and more affordable than ever, but you have to ensure you use the best possible solution.
Attune offers state-of-the-art IoT-powered sensors for real-time VOC detection, where managers can monitor reporting directly through the app and central platform. It's also fully customizable and fits painlessly into any existing infrastructure. VOC air quality sensors have never been more important, and with Attune, they've never been easier to install and use. So why wait?
Check out how our indoor air quality solutions arm your building for the fight against VOCs and sign up for a free demonstration today.
