COVID and indoor air quality – picking accurate sensors out of the crowd?

The COVID-19 pandemic has made indoor air quality (IAQ) a top priority for any organization whose members operate in an indoor environment. Laboratories, hospitals, offices, schools – all must now recognize the risks of airborne transmission, and they must all implement the necessary safeguards to ensure healthy indoor environments.

This new reality has spurred a rush to market by vendor companies offering IAQ solutions. New marked entrants are pushing a range of air quality monitoring technologies. These sensors try to measure parameters most important for human health — carbon dioxide (CO2); total volatile organic compounds (TVOCs); airborne particulates; relative humidity; and carbon monoxide (CO).

With new IAQ products came a flood of misinformation. If you’re a building owner or manager, the sudden explosion of IAQ options can be confusing and overwhelming. As an engineer you now have many options, but which sensors are best for your client? You know you need to up your IAQ game, but you might not yet have full command of all the relevant information you need to make this critical investment.

Aircuity is here to help.

In a series of posts to follow this introductory blog, we will highlight several of the complex challenges inherent with IAQ monitoring. Our goal is to give you insight to this area based on our more than 20 years of experience operating at more than 1,000 customer sites — including in labs, where air quality is of the utmost importance. We calibrate 7,000 sensors per year, more than any other company, so we really understand how these devices do and do not work.

We’ll tell you what you need to know, focusing on the following problem areas of IAQ monitoring:

  1. Sensor “Drift”

This post examines how all air quality sensors become increasingly more inaccurate over time. This “drift” has been documented by 3rd party studies for CO2, but less so for the other four IAQ parameters. We’ll explain how the “puck” sensors entering the market are especially vulnerable to such drift, why remote calibration doesn’t work, and the consequences of inaccuracy.

  1. Sensor Failure

We will review the average life of sensors – which is 1-3 years – and the frequency with which internal sensing elements need replacement. We will also examine the life cycle of particle and CO2 sensors, among others, and the long-term costs of puck-style sensors.

  1. Differential Measurement

Even with commercial grade sensors that are regularly calibrated , there is inherent inaccuracy. We’ll dive into this design and why it is important.

We hope these posts are useful to you as you decide what your IAQ monitoring needs are. Feel free to suggest other topics, or share comments as you go through this educational blog series.