Measuring Pollution with the Renesas ZMOD4xxx Lineup of Air Quality Modules
The ZMOD4410 and ZMOD4510 are air quality sensing modules that can measure both indoor and outdoor pollution using very little power.
Air Pollution Tracking
Air pollutants such as CO2, volatile organic compounds (VOCs), ozone, and nitrogen oxides can all have a negative impact both on the environment and our own health. A few government agencies, including the EPA and NASA, track these molecules using an array of ground-based detectors and satellites. From this data, maps are constructed that detail both where the pollutants are located as well as how much, which allows for other agencies and companies to respond accordingly.
This system is quite accurate, but it has the added drawbacks of being expensive and taking up large amounts of space/power to operate. On the other hand, a network of distributed internet-of-things (IoT) might be able to result in a lower overall cost while still maintaining a high degree of accuracy, which is what the ZMOD4xxx lineup from Renesas aims to accomplish.
The ZMOD4410
The ZMOD4410 sensor package is targeted for applications that require knowledge of the current indoor air quality (IAQ), such as air purifying systems, monitors, and other smart devices. Its firmware can distinguish between varying levels of total volatile organic compounds (TVOCs), estimated CO2 concentrations, and determine what kinds of sulfur-based odors are present in the ambient air. Rather than using the traditional methods of light scattering or infrared intensity, the ZMOD4410's metal oxide-based sensor measures the resistance of various gases and then passes that data to its firmware for further analysis. In doing so, power consumption can be as low as 160 micro-watts for battery-powered devices.
Getting started with the ZMOD4410 is pretty simple. Check out Monica Houston's Getting Started project tutorial where she uses the ZMOD4410 indoor air quality hat and a Raspberry Pi 3 to measure the air quality at home during the Washington State wildfires. She walks through how to set up your Pi and how to read the measurements.
The ZMOD4510
Unlike the ZMOD4410, the ZMOD4510 is meant for measuring outdoor air quality (OAQ) instead. Its integrated metal-oxide chemresistor conditions the ambient air sample and outputs a resistance reading, which correlates with the transportation/industrial pollutants ozone and nitrogen dioxide. From here, the values are fed into either a traditional or embedded machine learning algorithm that computes the resulting OAQ. Additionally, selective ozone measurements can be taken in an ultra-low power mode that only creates a power draw of a mere .2mW.
A getting started project tutorial for the ZMOD4510 can be found here. I set up a solar panel and battery outside and measured the air quality over the course of 24 hours. The different measurements throughout the day showed interesting trends as a result of wind and local car pollution.
Intelligent applications
Having the ability to accurately measure the current levels of various pollutants in the ambient air, both indoors or outdoors, can have a significant impact on how governments and private industries approach pollution measurements. A smart city might deploy several along each street to ensure the number of cars doesn't go above a certain threshold, and an office building might want to monitor the current CO2 level for worker health.
To get started with the ZMOD4410 and ZMOD4510 or learn more about the entire Renesas RZ product family of microprocessors, check out the Avnet landing page. Enter into their hardware giveaway to be considered for a free board in the coming months.