BBC Click recently did a segment on air quality devices called Breathe Easy? Air pollution trackers put to the test, where 4 monitors were stacked up to each other against a sophisticated reference air measurement instrument used at a local university. So how did each measure up? And what makes these devices so different?
The devices were tested for accuracy and user interface. The first up was ATMOTUBE, which gave a reading of 0.22 ppm and read ‘good’ air quality. Professor Roy Harrison using an industrial reference method Nitrogen Dioxide [RM NO2] monitor said he would give it a reading of ‘average’ air quality.
What is confusing to the average Joe is that none of these devices are testing NOx (Nitrogen Oxides) in the same way as the RM NO2 monitor. The professor is comparing the data and using his expertise in gas detection to communicate how each device performs. The ATMOTUBE says it monitors VOC’s or volatile organic compounds. It is giving a reading for carbon monoxide but within the reading of total VOCs. It does NOT have a selective carbon monoxide sensor (this distinction is not made that clear in the video).
CleanSpace tag read 1.5 ppm which the Professor concluded was an accurate level in comparison with his NOx device. So what makes this device different from the ATMOTUBE? The CleanSpace Tag has a carbon monoxide sensor and does not respond to VOCs. He describes this type of sensor, one selective to CO, as more predictable than relying on volatile organic compound sensors that measure a larger range of substances, potentially leading to more variability and less correlation to the reference pollution instrument’s measurement. Instead of using an algorithm to ‘guess’ or extrapolate CO levels, the CleanSpace measurement is based on the readings of an electrochemical carbon monoxide sensor directly reading the amount of CO in the air.
The I-Blades phone case got off to a rough start out of the gate. The host Lara Lewington noticed that the device reads zero when the app is open. From there it goes up or down based on how the air changes. Unlike the other devices they were completely unable to compare this readout to the reference monitor. Like the ATMOTUBE the I-Blades is using a sensor that measures VOC’s along with temp, pressure, and humidity.
Flow by Plume Labs
The last device put to the test was Flow by Plume Labs, a company known for bringing awareness to air quality with projects like the Pidgeons’ with air quality monitors. This device unfortunately gave no numbers for the professor to work with. He gave the device the benefit of the doubt knowing that it was responding to measurements of NOx and VOC’s, but sadly the device just said High Pollution. While he gives credit to the correlation to world health standards, the high pollution reading was not in line with his reference monitor readings.
Unlike the other devices, Flow measures NOx in addition to VOC’s. NOx is a common pollutant from Diesel emissions and a major concern for cities in England and Europe.
The manufacturers hope to add sensors for particulate matter, common lung irritants in polluted environments, and Ozone. The prototypes in the video do not yet have all those sensors. The Flow app may change as this product is not due for release until later this summer.
In conclusion, it appears that there are two elements that consumers will need to get on board with air quality devices. First, the app must give clear, relevant, and actionable information that educates the user about the meaning of sensor readings and then what to do about it [from get to some fresh air or write your legislator!]. The average individual may not have any awareness of what 1.5 ppm of CO means, but will be able to understand when this reading moves up and down from more to less polluted situations.
Secondly, the device must give accurate information. Ms. Lewington and the Professor were less impressed when the readings of the devices did not match the reference monitor readings. This is because the reference monitor is measuring a specific target pollutant and provides a clear distinction between high and low levels.
The challenge for these devices is to put reliability, accuracy, and interpretation of the readings together with ease of use in such small packages. This will translate into increased awareness of air quality for the user, peace of mind, and protection from dangerous situations.