How does Aura measure Air Quality?

What is AQI?

Aura Air’s Air Quality Index (AQI) was developed based on academic research, national AQIs, and other important considerations.

The AQI scale goes from 0 = 'Excellent' to 500 = 'Hazardous' with 6 color-coded categories of equal lengths, as you can see here:

What does the device measure?

Indoor AQI

CO

Carbon Monoxide (CO) is a poisonous gas that is produced from burning fuels such as wood, oil, natural gas, kerosene, coal, and gasoline. Because CO is invisible, odorless, tasteless, and non-irritating, the gas can cause harm before you are aware of its presence. CO is measured in PPM (parts per million).

CO2

Carbon dioxide (CO2) is the gas that people and plants exhale while breathing. Different levels of CO2 in the air can mean different things and cause different side effects based on each level. Levels are measured in PPM (parts per million).

VOCs

Total Volatile Organic Compounds are a large group of chemicals that can be found in many products we use to build and maintain our homes. Once these chemicals are in our homes, they are released or “off-gassed” into the indoor air we breathe. VOC levels are measured in ppb (parts per billion).

PM 10

Particles in the PM10 size range are commonly present in the air and could be drawn into the body with every breath. In our lungs, particles can have a direct physical effect and/or be absorbed into the blood. Technically, there is no safe level of PM10, as any amount of particulate matter in your air isn’t a good thing. The recommended normal level of PM10 should be 100 micrograms per cubic meter.

PM 2.5

Fine particulate matter (PM2.5) is an air pollutant that is a concern for people's health when levels in the air are high. PM2.5 are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated. PM2.5 is measured every 24 hours in micrograms per cubic meter.

Outdoor AQI

The outdoor AQI (Air Quality Index) presented is based on EPA's national air quality standards.

The AQI scale goes from 0 = 'Excellent' to 500 = 'Hazardous' with 6 color-coded categories of equal lengths. AQI’s often vary between countries.

NO2

Nitrogen oxides are a group of seven gases and compounds composed of nitrogen and oxygen.  They are emitted from vehicle exhausts; the burning of coal, oil, diesel fuel, natural gas, and especially from electric power plants. They are also emitted by cigarettes, gas stoves, home heating appliances, and wood-burning ovens. The EPA (the United States Environmental Protection Agency), has set up a 1-hour NO2 standard at the level of 100 parts per billion (ppb). The annual average of standard NO2 is 53 ppb.

O3

The ozone is a gas that occurs both in the earth’s upper atmosphere and at the earth’s ground level. In the upper atmosphere, the ozone protects life on earth from the sun’s harmful ultraviolet rays. The ozone on the ground level is the main ingredient of smog. It is formed when sunlight reacts with pollution from vehicles, power plants, and industrial sources. Ozone pollution is the worst in the afternoon and early evening. The ozone standard is set at a level of 0.075 ppm averaged over an 8-hour period. This standard is met at an air quality monitor when the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentration is less than or equal to 0.070 ppm.

SO2

Sulfur dioxide is an invisible gas that has an unpleasant, sharp smell. It reacts easily with other substances to form harmful compounds, such as sulfuric acid, sulfurous acid, and sulfate particles. An AQI of 100 for sulfur dioxide corresponds to a level of 75 parts per billion (averaged over one hour). Sulfur Dioxide (SO2) is generally recognized between 0.3-1.4 ppm and is easily noticeable at 3 ppm. It can be detected by taste at concentrations of 0.35-1.05 ppm and has a strong and irritating smell. The odor threshold is between 0.67-4.75 ppm.