FAQ

Both the AirU+ and AirU Pro are excellent options for monitoring air quality, but they cater to different needs.

• AirU+: Ideal for individuals or smaller scale monitoring, the AirU+ provides reliable data on PM2.5, which is a key indicator of overall air quality.
• AirU Pro: Perfect for those requiring comprehensive air quality data, the AirU Pro features a modular design that allows users to expand their monitoring capabilities. This model can measure a wide range of pollutants that contribute to the Air Quality Index (AQI), including PM, O3, CO, SO2, and NO2. It is also well-suited for specific environments like water treatment facilities, construction sites, and refineries. Moreover, the Pro model supports advanced communication options, including LTE connectivity, making it a robust choice for both individual and community-level applications.

In summary, if you need basic air quality monitoring focused on PM2.5, the AirU+ is a great choice. However, if you require a more detailed and expandable monitoring solution, the AirU Pro is the best option.

The AirU+ is a highly capable air monitoring solution, especially if your primary focus is on monitoring PM2.5, and you have access to Wi-Fi and a power source. In this scenario, the AirU+ is a sensible choice.

Looking ahead, we are in the process of developing a new indoor monitor that will feature CO2 measurement capabilities and sport a sleek, indoor-friendly design. Alternatively, the AirU Pro, equipped with CO2 monitoring, can be an excellent choice for indoor air quality assessment.

AirU Legacy Sensor dimensions: 4” x 4” x 4”.

AirU+ Sensor dimensions: 4.7″ x 4.7″ x 2.4″.

AirU Pro Sensor dimensions: 7.6″ x 5.3″ x 3.6″.

The AirU can hang from a hook under an overhang (like a plant), or mounted on a wall, like a smoke detector.

Ideally, the sensor should be mounted in a sheltered outdoor location, such as under an eave. Ensure that the sensor receives a strong Wi-Fi signal, with at least 2 bars on a mobile device. While the AirU’s protective housing is water-resistant, it is not waterproof. Mount the AirU at roughly breathing level (5 feet or higher) and avoid placing it near kitchen exhausts, dryer vents, or less than 4 feet above the ground. The sensor also needs to be connected to a power source.

The AirU consumes approximately 1.5 Watts.  The cost of power varies by location, but it will cost less than 1 cent per month.

• What if my AirU goes offline?
  • Ensure that your sensor has power. If not, provide power.  If it has power unplug it for 10 seconds, and plug it back in.  If it does not come back online contact us at help@TELLUSensors.com.
• What if my PM2.5 concentrations are 0 ug/m3 for more than 48 hours?
  • Ensure that your sensor has power.  If not, provide power.  If it has power unplug it for 10 seconds, and plug it back in.  If it continues to read zero, contact us at help@TELLUSensors.com.

• What if my PM2.5 concentrations remain constant (i.e., 4 ug/m3) for more than 24 hours
  • Unplug your sensor for 10 seconds, and plug it back in. If the numbers still do not change, contact us at help@TELLUSensors.com.
• What if my PM2.5 concentrations fluctuate by more than 50% on a minute-by-minute, basis?
  • PM2.5 levels can fluctuate greatly on a minute-by-minute basis.  Although we are interested in minute-by-minute readings.  It is more important to determine if your sensor generally follows air quality trends.
• What if my PM2.5 concentrations show an unhealthy level > 150 ug/m3 that lasts for a few minutes
  • This can be normal, and there may be many causes.  One larger particle may have passed through the sensor and provided an erroneous reading, or a malfunctioning vehicle/an individual smoking a cigarette may be near the sensor.

Communities can gather spatially dense air quality measurements by having members host sensor nodes, providing power and Wi-Fi connectivity. These sensor nodes send measurements to a cloud database, where the data is quality assured, visualized on a map, and available for download. Once a critical mass of sensors is deployed, the measurements can be integrated. These visualizations help communities interpret the somewhat imperfect data from the sensors. Each sensor node may measure multiple pollutants, with particle pollution being a common indicator due to its significant impact on health. With proper quality control, these measurements can provide reliable estimates of air quality. Depending on the pollutants measured, sensor nodes typically cost a few hundred to several thousand dollars.

Regulatory measurements must meet strict siting and quality control standards, and they require dedicated maintenance. This equipment typically costs thousands to tens of thousands of dollars per pollutant. Its level of expense and quality control is required for regulatory purposes.

Data quality is one of the biggest challenges with crowd-sourced sensor measurements. The sensors can malfunction or located indoors rather than outdoors. Some pollutant measurements are sensitive to environmental conditions (i.e., temperature, humidity and composition of the species in the air). It is critical for malfunctioning sensors and to develop appropriate corrections for the environment. These corrections typically rely on state and regulatory agencies that allow co-location of the crowd-sourced sensor node with their high-quality regulatory monitors.

Crowd-sourced air quality measurements are typically presented as dots on a map, but this can be difficult to make sense of. Oftentimes, sensors in close proximity may read disparately, which may reflect reality or malfunctioning sensor nodes. One way to improve this difficult-to-interpret data is to incorporate the screened and environment-corrected measurements into a regression model, with appropriate functions s for distance, time and elevation to obtain continuous-valued spatio-temporal estimates of air quality throughout a region.

Low-cost PM sensors use a laser scattering principle, which works by using a laser to radiate suspended particles in the air. The scattered light is then collected by an internal photodiode, and finally the curve of scattering light change with time is obtained. Finally, equivalent particle diameter and the number of particles with different diameter per unit volume can be calculated by microprocessor based on MIE theory.

The conversion from light scattering to particle concentration measurements depends on the size and number of particles passing through the laser, as well as their optical properties. Different particles scatter light differently due to their shape or chemical makeup, which affects the light received by the photodiode and the final concentration measurement. For instance, optical PM sensors often overestimate concentrations of wildfire smoke or winter pollution, but can underestimate firework smoke by up to 2x. Environmental factors like humidity also significantly impact sensor readings. Therefore, it’s crucial to keep sensor calibrations up-to-date based on the current environment.

Our team takes care to calibrate each sensor in our lab. The PM2.5 sensors are quite stable and hardly change over their lifetime since they’re optical sensors. However, our gas sensors can drift a bit after about a year or so, and we generally recommend replacing them within 18 to 24 months.

We offer seasonal calibration updates, about four times a year, for our sensor network users, mainly researchers or anyone looking to fine-tune their data. It’s a service that’s typically more popular with our bigger sensor network users.

We perform multi-variable regional calibrations for all PM sensors using ground-truth data from local Federal Equivalement Method (FEM) or Federal Reference Method (FRM) sources. FEMs/FRMs are very high-quality monitoring instruments, typically maintained by the EPA, which produce reliable hourly PM concentration measurements. We collect measurements from these gold-standard sources and compare them to nearby low-cost monitors to provide accurate, up-to-date calibrations that are directly traceable to these ground-truth sources. We periodically recompute and update these calibrations to consider the latest environmental parameters of the region.

Ensuring optimal performance of your AirU unit is crucial for accurate air quality monitoring. To achieve this, it’s essential to maintain unobstructed airflow at the bottom of the unit. Both the AirU+ and Pro models rely on this unobstructed pathway for the intake and exhaust of air samples. By keeping the bottom of your AirU clear, you’re not only guaranteeing precise data but also ensuring that your investment in clean, healthy air is maximized.

The AirU monitors have a rich history rooted in outdoor applications. Originally conceived for outdoor use, these monitors have proven their resilience over more than five years of deployment in diverse regions across the United States. Notably, they have excelled in extreme conditions, from the scorching heat of Las Vegas to the freezing cold of Alaska.

Their adaptability and robust performance in challenging environments stand as a testament to their engineering excellence. While Alaska’s extreme cold presented unique challenges, no such issues have arisen elsewhere, reaffirming the monitors’ reliability and effectiveness in providing accurate air quality data.

Both the AirU+ and Pro models are built to handle different weather conditions like rain, snow, and ice. They’re designed to keep water out, and the only openings are at the bottom, which is a pretty safe bet unless we’re expecting some truly strange weather where it rains upward.

They produce a bit of heat, which helps keep their electronic parts warm during chilly winter months. So, whether it’s sunny or snowy, they’ve got you covered for year-round air quality monitoring.

1. Make sure you are logged in to your account. If you are not logged in, you will not be able to see your device. 
2. Make sure you have the device selected (select the checkbox next to the device ID).

If you are still seeing an issue, please reach out to us at support@tellusensors.com and we’ll get back to you as soon as possible!

The humidity sensor found inside the AirU+ measures the relative humidity inside the device enclosure. This is helpful to understand device health and potential issues with the performance of the electronics. The humidity reading will effected by the elevated temperature of the device itself. As the temperature of the device increases, the humidity reading from the sensor is expected to decrease.

The AirU family of air quality monitors are equipped with sensors to monitor various air quality metrics, including temperature and humidity, which are crucial indicators for assessing the risk of mold growth. Mold tends to thrive in environments with high humidity levels (typically above 60%) and certain temperature ranges. By continuously monitoring temperature and humidity, your AirU provides insights into the environmental conditions that could promote mold growth.

While your AirU does not directly detect mold spores, its PM1/PM2.5 sensor and optional PM10 sensor can indirectly detect particles in the air that could indicate the presence of mold. Mold spores range in size from 1 to 100 micrometers, falling within the detection range of the PM1/PM2.5 and PM10 sensors. When mold spores become airborne, they can be captured by the PM sensors, alerting users to potential indoor air quality issues.

It’s important to note that while the PM1/PM2.5 and PM10 sensors can detect particles associated with mold, further testing may be required to confirm the presence of mold in a specific environment. Additionally, your AirU provides real-time data on temperature and humidity levels, allowing users to take proactive measures to prevent mold growth before it becomes a significant issue.

In summary, while your AirU can’t directly detect mold, it provides valuable data on temperature, humidity, and airborne particles that can help users assess the risk of mold growth and take appropriate actions to maintain healthy indoor air quality