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Cisco Meraki Documentation

MT14 Air Quality Sensor Metrics Explained


This article is aims to introduce and explain the metrics collected by the MT14 Air Quality Sensor. The qualitative ratings will also be explored, detailing how they are derived and displayed on the Dashboard.

Indoor Air Quality Rating

The Indoor Air Quality (IAQ) Rating is a unique qualitative aggregate rating that can be used as a general indicator for overall air quality. IAQ has five qualitative ratings; excellent, good, fair, poor, and inadequate. The rating system takes into consideration temperature, humidity, TVOC's and PM2.5. 


Each metric has a weight assigned to it based on the current reading and an aggregated score is calculated. Below is the range how the qualitative rating is assigned to the aggregated score:

  • Excellent: 93 to 100

  • Good: 80 to 92

  • Fair: 60 to 79

  • Poor: 40 to 59

  • Inadequate: 20 to 39

Refer to the sections below to see how each metric’s qualitative ratings are attributed to the IAQ calculation.

IAQ score calculation doesn’t include Ambient Noise measurement.

Temperature (°F/°C)

Temperature is defined as the degree or intensity of heat present in a substance or object, using scales in Fahrenheit or Celcius. Temperature affects comfort, productivity, and willingness to remain inside of a space. The Occupational Safety and Health Administration (OSHA) within the U.S. Department of Labor recommends 68-76°F (20-24.4°C) as the ideal range in the workplace. High temperatures can lead to heat stress and dehydration. Low temperatures can lead to dry air, impairment of the immune system, and general discomfort. [1]


Humidity (%RH)

Relative Humidity, (or %RH), is defined as the amount of atmospheric moisture relative to the amount that would be present if the air were saturated. Humidity levels affect comfort, productivity, and respiratory health. High humidity can lead to dehydration, heat rashes, and allergy-like symptoms. High humidity also promotes the growth of harmful mold, viruses, and bacteria. Low humidity can lead to dry skin, sinus irritation, and increased vulnerability to infection. [2][3]


TVOC (µg/m³)

Total Volatile Organic Compounds (TVOC) measures the total amount of VOC's in the area. VOC's include a variety of chemicals, such as paints, aerosol sprays, cleaning solutions, pesticides, and automotive products. They can also include chemicals from smoking electronic cigarettes (vaping). High TVOC levels can negatively affect comfort, health, and productivity. Symptoms associated with high TVOC's include sinus irritation, headaches, nausea, and damage to the liver, kidneys, and nervous system. Some VOC's are also known to cause cancer in humans. [4][5][6]

The readings obtained by the sensor is representative of the total amount of chemicals in the environment. Individual concentrations of each chemicals present in the sampling is not provided.

TVOC Refinement Period

On first boot, the TVOC sensor undergoes a refinement period of approximately 48 hours, where it calibrates the sensor, taking its current environment as baseline. MT14's TVOC accuracy varies depending on environmental conditions; MT14 readings become more accurate over time if TVOC levels are kept low the majority of the time.


PM2.5 (μg/m3)

PM2.5, where (µg/m3) is defined as microgrammes per cubic meter, is particulate matter that is smaller than 2.5 micrometers. These particles are small enough to permeate the mucous membranes in the lungs and can even enter the bloodstream. PM2.5 comes from automobiles, construction sites, industrial facilities, fires, smokestacks, cooking fumes and vaping fumes from e-cigarettes. Prolonged exposure to PM2.5 can lead to respiratory irritation, decreased lung function, heart disease, cancer, and even premature death. [9]


NOTE: External power is required to collect PM2.5 data from MT14

Ambient Noise (dBA)

Ambient noise(dBA) is the background sounds that are present in a scene or location. Ambient noise levels affect comfort, productivity, and hearing health. High ambient noise can make it difficult to concentrate or communicate with others. If ambient noise exceeds 85 decibels for extended periods of time, hearing damage and long-term hearing loss can occur. [10]


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