A Guide to Indoor Air Quality Measurement Techniques and Application

The US Environmental Protection Agency (EPA) has defined indoor air quality as “the quality of air in a home, school, office, or other building environment.” Studies have shown that indoor air pollution is a contributing cause of death, lower average life expectancy, higher rate of health issues, lower cognitive functioning and decreased work efficiency. So it is important to know how to measure air quality and what can be done to improve it?

1- Reducing Contaminants

There are numerous potential contaminants to reduce from our indoor environments. Some of these are pulled in from outdoors while others emanate from indoor sources. The most common pollutants are the following.

• Volatile organic compounds (VOCs)- Unfortunately VOC’s can be readily found both indoors and outdoors. VOCs are organic chemicals that get emitted as gases from common household products or processes; most of the time we can smell them. Common sources of indoor VOCs include cleaning agents, disinfectants, air fresheners, dehumidifiers, paints and others. VOC contamination pulled in from outside may come from outdoor air pollution or volatile chemical pollution in groundwater..

• Particulate matter (PM)- PM is prevalent both indoors and outdoors and is a mixture of solid particles (dust, pollen, smoke, and soot) and liquid droplets suspended in the air.  These particles differ widely in size, but the most dangerous are the ones that can be inhaled (those 10 micrometers in diameter or smaller). When we inhale PM it can affect our heart and lungs. Outdoor PM from construction or the burning of fossil fuels for example, enters into buildings through windows or ventilation systems. Indoor PM can be produced by fireplaces, cooking, cigarette smoke, etc.

• Carbon monoxide (CO)- Unlike VOCs, carbon monoxide cannot be smelled, tasted, or seen. If present in low and moderate concentrations it causes fatigue, chest pain, or impaired vision; but in high concentrations it can be fatal. Some sources of carbon monoxide are generators, boilers or furnaces that have not been properly maintained or automobile exhaust.

• Further pollutants to consider are Radon, Carbon dioxide, Nitrogen dioxide, Methane as well as other less common pollutants.

2- Improving Ventilation

The EPA defines ventilation as a “combination of processes which results in the supply and removal of air from inside a building.” It is the process of bringing in outside air, conditioning it (heating or cooling), mixing it with indoor air, distributing the mixed and conditioned air throughout the building, and transferring a portion of indoor air back outside. A problem with any one or more of these processes will affect the quality of indoor air. Therefore fixing or improving any or all of these processes will.improve indoor air quality.

3- Achieving comfortable humidity and temperature levels

Although these levels primarily contribute to the comfort of those indoors, something like humidity can also lead to the potential for mold growth if left unchecked. The EPA recommends that indoor air humidity levels remain between 30 and 60% while indoor temperatures range from 68.5 to 75 degrees Fahrenheit in the winter, and from 75 to 80.5 degrees in the summer.

Things like temperature and humidity are rather easy to measure, however measuring pollution levels is much more challenging. Although there have been marked improvements in air quality analysis methods and indoor air quality monitoring systems, knowing what the problem pollutants are is the key to success. Monitoring systems generally work best when it is known what they should be looking for and have been programmed to look for those specific pollutants already known to be present in a specific environment.

Knowing how to measure indoor air quality is vital so it is great to begin with professionals. If you have concerns about the quality of your indoor air, contacting Torrent Laboratory to do a complete indoor air quality test is a great place to start because our chemists will give you a full breakdown of any and all problems and will be available to answer any questions you may have concerning the process, the issues, specific contaminants and/ or the solutions.

Once a full and complete test has been completed then ongoing systems for monitoring and measuring the indoor air quality will be implemented to improve the overall indoor environment immediately and long term.

Air quality measurement is vitally important because:

• Indoor air quality affects how effectively we are able to work, learn, and play.
• It also has long-term health implications.
• Monitoring provides information about potentially harmful contaminants, like radon, total VOCs, CO₂, and our indoor living conditions like temperature and humidity that affect the quality of the air we breathe.
• This information empowers us to take action to improve indoor air quality for our families, and employees by ventilating our homes and workplaces better, changing the products we use, or improving our buildings.
• Indoor air is equally important in schools and daycare, where it affects children’s ability to learn.
• Raising awareness about indoor air quality and its importance to our overall health may create a movement to protect future generations from preventable diseases like lung cancer.

Indoor Air Quality Sensors

Air quality measurement is best monitored by indoor air quality sensors. Each sensor is programmed to detect the presence of a particular pollutant. Different types of sensors are used to measure for different pollutants. Advanced technology has led to the creation of smaller, less expensive sensors, but these still need to be placed strategically throughout your building to produce reliable results. (The EPA recommends one sensor for every 10,000 square feet.) Core air quality analysis methods use these sensors to measure:

• Carbon monoxide
• Particulate matter
• VOCs
• Humidity
• Formaldehyde
• Radon

However, sensors are capable of measuring methane, bioaerosols, and more. Therefore depending on your specific needs, it is possible to measure pollutants beyond those listed.

Sensor Placement

Sensors are usually placed throughout a building in the common areas but not near induction units, floor fans, or personal heaters, and out of direct sunlight. Wall mounts are best because floors and ceilings are not necessarily indicative of an actual environment.  Depending on what particular pollutants are being measured placements will be made at various heights to best identify those pollutants. Heavier pollutants will collect near the floor while lighter ones will be detected best at the ceiling.  Still most sensors will be at or below the height of most people standing or sitting in order to measure at the level of greatest ingestion.  

Excellent air quality measurement begins with quality indoor air quality testing from experienced, reputable and certified environmental testing laboratories like Torrent Laboratory.  

1. Torrent is the premier environmental testing laboratory for California and Hawaii.
2. We have the fastest TAT’s in the industry and unparalleled on-time performance when getting results back to our clients.
3. Torrent Laboratory’s ambient air testing services are certified by the Department of Defense (DoD) ELAP. Clients have a greater level of confidence in our data, knowing it must meet the high level of scrutiny required by ISO 17025:2017 DoD ELAP.
4. When looking for an air quality testing laboratory, Torrent offers the most impeccable record of quality service and testing results in the industry. 
5. Our customer support is timely, efficient and friendly.  And our technical support is unrivaled in its professionalism and expertise.

Torrent Laboratory provides the most advanced capabilities in the region. Our full-service lab offers a host of advantages including: 

• Highest certifications 
• Fastest possible TAT in the industry
• Unrivaled technical and customer support
• Unparalleled on-time performance
• Impeccable quality 
• Competitive pricing 
• Convenient geographic location

Trust Torrent as your premier environmental testing laboratory for California and Hawaii.