AirGradient ONE Chapter 1 — Getting Started Unboxing the AirGradient ONE An AirGradient ONE box contains: 1x Fully-Assembled AirGradient ONE (Model: I-9PSL-DE) 2x Stands for AirGradient ONE ( How to install the stands? ) 1x 90-degree USB-A to USB-C cable (2m) 1x Thank You Card (QR code links to onboarding instructions) 1x Regulatory & Safety Insert Powering the AirGradient ONE Use a standard 5V, 2A USB power supply (not included). Most phone chargers meet this requirement. You will likely have one of these lying around your house from a smartphone or another device. Connect the USB-C end of the included cable to the AirGradient ONE Connect the USB-A end to the USB power supply Plug the power supply into an AC outlet Power-related issues If the device does not turn on, restarts unexpectedly, or shows unstable behavior (such as sudden CO2 spikes or missing PM data), the power supply is the most likely cause. What to do Try a different USB power adapter Avoid low-quality or low-current chargers Do not power the device from a computer USB port or underpowered hub Stable power is critical for reliable operation. Connecting Your AirGradient ONE to WiFi Prerequisites Before connecting your AirGradient ONE to WiFi, make sure you have: A Compatible WiFi Network Your WiFi network must meet the following requirements: 2.4GHz only (5GHz is not supported) Must have active internet No WPA Enterprise authentication No captive portals (hotel/guest login pages) No firewall blocking unknown devices (The monitor’s serial number = MAC address for whitelisting.) A Smartphone, Tablet, or Laptop with WiFi You will use this device to connect to the monitor’s hotspot and complete WiFi configuration. Video Guides (Watch First if You Prefer Video Instructions) If you’d rather follow video instructions instead of the written steps, use the one of the video guides below. These cover all onboarding methods: QR-code and manual WiFi selection. QR Code vs. Manual Wi-Fi Selection – What’s the Difference? All pre-assembled AirGradient ONE units include a printed QR code on the enclosure. Scanning it simply skips the step of manually searching for the hotspot and connects you directly to the device’s WiFi network: airgradient-xxxxxxxxxxxx (Where xxxxxxxxxxxx is your device’s serial number. If you’re setting up a DIY kit, you may want to note down the Serial Number for dashboard onboarding later.) DIY kit units do not have the QR code, but the setup process is identical – you just join the hotspot manually from your WiFi settings. Regardless of which method you use, the actual WiFi configuration steps are the same, choose a video below based on your setup and preference: Connect to WiFi – iOS AirGradient ONE – Connect to Wi-Fi AirGradient ONE – Connect to Wi-Fi using QR Code Connect to WiFi – Android AirGradient ONE – Connect to Wi-Fi  AirGradient ONE – Connect to Wi-Fi using QR Code 1. Connecting Your AirGradient ONE to WiFi 1.1 Power On Plug the ONE into a stable USB-C power source. The device display will show initialization messages. After booting, the screen will show the following message: 180s to connect to airgradient-xxxxxxxxxxxx (Where xxxxxxxxxxxx is your device’s serial number. If you’re setting up a DIY kit, you may want to note down the Serial Number for dashboard onboarding later.) This is the hotspot name. 1.2 Connect to the Device Hotspot As mentioned in the Video Guides section above: All pre-assembled AirGradient ONE units include a QR code printed on the back of the enclosure. Scanning it connects you directly to the device’s WiFi hotspot. You can still join the hotspot manually if you prefer - the setup process is otherwise identical. Option A:  Scan the QR Code (pre-assembled units) Scan the QR code on the back of the enclosure. Your phone will prompt you to join the WiFi network: Tap Join. (this skips the step of manually locating the hotspot) Option B:  Join the Hotspot Manually (all units, including DIY kits) Open your phone, tablet, or laptop WiFi settings. Look for and select the network: airgradient-xxxxxxxxxxxx Enter the password:  cleanair Android notes Android 11/12 may show Manage router → tap it. Some versions require tapping “Tap here to sign in to network” to open the WiFi Manager. 1.3 Open the WiFi Manager Once connected to the hotspot, the WiFi Manager should open automatically within ~10 seconds. If it doesn’t: Open a browser. Go to: 192.168.4.1 (Enter it in the address bar, not a search engine.) Make sure you are still connected to the device hotspot. Turn off mobile data while you’re connected to the device hotspot as it may cause the smartphone to temporarily switch to mobile data instead of maintaining the device hotspot connection. 1.4 Configure Your WiFi Network On the WiFi Manager page: Tap Configure WiFi Select your WiFi network For hidden networks, enter the SSID manually. Enter your WiFi password (This should be your router password, not “cleanair”.) Ensure “Prevent connection to AirGradient servers” is unchecked, if you want the devices to connect to the AirGradient dashboard and receive automatic firmware updates. Tap Save 1.5 Credential Saving & Expected Behavior You’ll see: “saving credentials…” Stay on this page. Do not disconnect. If the password is correct → the window closes automatically. If incorrect → you are returned to the network list. If the captive portal times out → the device reboots. Reconnect to the hotspot and start again. If the window closes without showing “saving credentials…” → it still means success. “No Internet Connection” warnings: Totally normal. Stay connected to the hotspot until the process completes. Next Steps After Connecting Your AirGradient ONE will now connect to WiFi and start transmitting data. To link it to your dashboard: How do I connect my AirGradient ONE to the AirGradient Dashboard? Frequently Asked Questions Can the AirGradient ONE use 5GHz WiFi? No. The ONE only supports 2.4GHz. The hotspot doesn’t appear. What now? Reset the device and try again. Ensure you are close to the monitor. Which network types are not supported? WPA Enterprise Captive portals What is the device hotspot password? cleanair The WiFi Manager screen didn’t appear. Go to 192.168.4.1 in your browser (while connected to the hotspot). Turn off mobile data while you’re connected to the device hotspot as it may cause the smartphone to temporarily switch to mobile data instead of maintaining the device hotspot connection. My phone says “no internet connection” when connected to the hotspot. Ignore it. This is expected and does not affect setup. The monitor won’t connect to WiFi. Check: Correct WiFi password Network is 2.4GHz No firewall blocking devices Then retry the setup. The captive portal timed out. The monitor restarts automatically. Reconnect and repeat the process. How do I connect my AirGradient ONE to the AirGradient Dashboard? There are two ways to add your AirGradient ONE to the dashboard. You can: connect the monitor to Wi-Fi first  or Follow this guide and add the monitor to the dashboard first. The order does not matter. However, the device will not send any data to the dashboard until both steps have been completed.  Add to dashboard using the QR code (pre-assembled units) If you have a pre-assembled AirGradient ONE, you can add it using the “Add to Dashboard” QR code printed on the back of the device. Scan the Add to Dashboard QR code You will be taken to the AirGradient Dashboard: https://app.airgradient.com/ Log in, or create an account if you don’t already have one The monitor’s serial number will be pre-filled Pick which dashboard (Place) you want to associate the monitor with (if you have multiple) or create a new Place (Link to article on difference between Place and Location?) Enter a location name for the monitor Select the exact model number. For assembled monitors, this is printed on the back of the monitor: If you’re unsure, see:  AirGradient Models Click Add The monitor will now appear in your dashboard. You should see an entry for the monitor on your dashboard, but it will likely show as offline for the first minute or two. Please allow up to five minutes for the monitor to show as online and for the data to begin reporting.  Add to dashboard manually (Kits or QR code not working) If you have a DIY kit, or if the QR code does not work, you can add the device manually: 1. Open the monitor onboarding guide . 2. Select the monitor type that you are trying to connect to your dashboard. In this case, you need to select the AirGradient ONE. 3. Select the exact model number. For assembled monitors, this is printed on the back of the monitor but for DIY kits, it is not. For the AirGradient ONE the latest model number is generally either: I-9PSL-DE (Standard Wi-Fi Version) I-9PSL-DE-CE (Cellular Version) If you’re unsure, see: AirGradient Models 4. Pick which dashboard (Place) you want to associate the monitor with (if you have multiple) or create a new Place (Link to article on difference between Place and Location?) 5. Enter the serial number (SN) of the monitor.  For assembled monitors, the SN printed on the back of the monitor but for DIY kits, it is not. To find the SN for the DIY kits, when you startup the monitor, you can see a message “180s to connect to WiFi Hotspot airgradient-xxxxx”. The xxxxx is the serial number of the monitor. Please make sure that you use it in lower case only and also do not use “airgradient-” which is not part of the serial number. So if for example, the display shows “airgradient-625bf2”, then “625bf2” is the serial number. 6. Enter a location name for the monitor and click Add 7. You will next be provided with the steps to connect the device to your WiFi network. If you’ve already connected the device to your network, you can skip this step and click Next Step. Finally, click To Dashboard.  The monitor will now appear in your dashboard. You should see an entry for the monitor on your dashboard, but it will likely show as offline for the first minute or two. Please allow up to five minutes for the monitor to show as online and for the data to begin reporting.  If you don’t begin to receive data after five minutes, please confirm that the serial number  Adding an additional monitor to an existing dashboard If you already have an AirGradient dashboard and the device is already connected to Wi-Fi: Go to Dashboard > Hardware Click Add New Enter: Serial number Maker: AirGradient Model Click Save Please note that adding a hardware entity alone is not enough. To see data, you must also create a Location and assign the monitor to that location. If a location is not created and linked to the hardware entity, the device will appear in the dashboard but you will not see any data until you also create a Location and tie the monitor to that location. How do I mount or place the AirGradient ONE properly? The AirGradient ONE comes with multiple mounting and cable-management options, making it a flexible air quality monitor that can be mounted on a wall or sat on a desk (using the included stands). The four holes located on the top, bottom, left and right of the device allow it to be mounted on a wall via a M4 screw or screws. These holes align with U.S. and EU junction boxes. While the device will be secure with just one screw at the top of the monitor, it can easily be tilted or turned off-axis, so we recommend using the left and right mounting holes if possible, preventing any movement of the device. If you want a temporary installation or prefer to have the monitor on a desk or shelf, we also include two plastic stands that can be slid into the vents at the bottom of the device. These feet allow you to stand the monitor on any flat surface easily.  While it depends on the installation, we generally recommend routing the cable downwards through the channel on the back of the device if using the included stands. If mounted on a wall, you can either use the top or bottom channel, depending on your setup. It’s important to note that while any USB Type-C cable can be used with this device, only the included 2-metre 90-degree Type-C cable allows it to sit flush with a wall or any other surface it’s mounted on. Also, please note that the AirGradient ONE does not come with a USB adapter. Wall-Mounting Considerations Height: Please do not place the sensor below 100cm or above 300cm on the wall. Ideally, it should be placed between 150 and 250cm. Orientation: Ensure that the monitor is mounted on the wall in the correct orientation and has unobstructed airflow at the bottom and top of the monitor. Walls: Please ensure that the walls are not hot due to outside exposure, which might negatively influence the temperature sensor. Sunlight: To get accurate temperature readings, please ensure that the sensor unit is not exposed to direct sunlight at any time of the day, Doors/Windows: To ensure stable readings, we recommend not placing the sensor unit close to doors or windows. Air Conditioner / Ventilation Outlet: Please do not place the sensors closer than 90cm to any A/C or ventilation outlet. Furthermore, for the best results, avoid placing the device in front of an AC unit. Distance from Pollution Sources: Avoid placing the monitor too close to direct pollution sources such as ovens, fireplaces, or other localised emission sources that could skew the readings. Heat Sources: If possible, place the device away from heat sources such as large electronics/appliances. Desk-Mounting Considerations Alongside the above considerations for airflow (avoid proximity to pollution sources, keep the device out of direct sunlight, etc.), there are a few other considerations if you want to use the feet and place the monitor on a desk or shelf. Monitor Stands: Ensure you use the included stands for the monitor. These provide clearance at the bottom of the device, ensuring good airflow despite the venting facing the bottom of the device. Ventilation: Place the device somewhere with space around it. For example, placing the monitor on a bookshelf with only a few centimetres of clearance above the monitor can result in poor airflow and incorrect reading. You can download the PDF with instructions here . Resetting Wi-Fi Configuration / Connecting to a different Wi-Fi network You can perform a factory reset by pressing and holding the BOOT button on the back of the device for about 10 seconds. Here’s a video guide:  How to Perform a Factory Reset A countdown will show up on the screen. Please note that the data and settings made via AirGradient Dashboard won’t be deleted while performing a factory reset. Note for non-dashboard users: In case you don’t use your AirGradient ONE with the AirGradient Dashboard (i.e., local only via Home Assistant, Local API),  all configuration (including correction algorithms) made via these platforms will be gone. You will need to manually reconfigure your AirGradient ONE again on these platforms after the AirGradient ONE is reset and connected to the new Wi-Fi network. Troubleshooting Wi-Fi Connection Before continuing, make sure you have followed the Wi-Fi setup steps exactly as shown in the written instructions or video guides: Connecting Your AirGradient ONE to WiFi If the setup steps or videos were skipped, incomplete, or done in a different order, Wi-Fi connection issues are very likely. Only continue with the troubleshooting steps below after confirming the setup guide was followed correctly. If the WiFi network you want to connect your AirGradient ONE to doesn’t appear in the WiFi configuration settings, or the device fails to connect, it’s almost always due to one of the limitations below: 5 GHz Wi-Fi is not supported AirGradient devices only support 2.4 GHz WiFi. 5 GHz-only networks will not appear in the Wi-Fi configuration menu. A single (unified) SSID (WiFi name) that combines 2.4 GHz + 5 GHz can cause connection failures. This behavior depends on the router. Some routers with a single (unified) SSID for both 2.4 GHz and 5 GHz work fine. Others don’t, and may prevent the device from seeing the network or completing setup. If this happens, the best split the Wi-Fi into two separate SSIDs: one for 2.4 GHz one for 5 GHz Then, connect the device to the 2.4 GHz SSID Important Note The steps to split Wi-Fi radios vary by router manufacturer. In most cases, you need to disable “band steering”. Enterprise / managed networks are not supported AirGradient devices do not support enterprise or managed Wi-Fi networks, including WPA2-Enterprise or WPA3-Enterprise, certificate-based authentication, captive portals (login pages), or networks that require a proxy. These types of networks are commonly used in schools, universities, corporate offices, government buildings, hotels, and public Wi-Fi. If you are on such a network, contact your IT administrator and either connect the device to a standard 2.4 GHz personal Wi-Fi network or deploy it on a separate IoT / sensor-only Wi-Fi network. Firewall and outbound traffic restrictions Some networks block outbound traffic by default. If outbound access is restricted, the Wi-Fi setup may fail during setup or the device will appear “offline” on the Dashboard after setup. AirGradient devices require outbound HTTPS access only to :  91.98.9.143 Test Network Connectivity (Ping Test) If the device connects to Wi-Fi but shows offline in the Dashboard and the purple LED on the device in on, the network may be blocking outbound traffic. AirGradient devices require outbound HTTPS access to:  91.98.9.143 You can test basic network reachability from the same network using a computer. Run in a Terminal (iOS) or Command Prompt (Windows): ping hw.airgradient.com  Expected Result You should see replies similar to: 64 bytes from 91.98.9.143: icmp_seq=0 ttl=49 time=68.751 ms If you do not get a timeout response: The network is likely blocking outbound traffic Ask IT to allow outbound HTTPS traffic to 91.98.9.143 Hidden SSIDs Hidden networks usually won’t show up in the list. Enter the SSID and password manually in this case. Router security settings Some routers block new or IoT devices by default. Check for: MAC filtering: use the device serial number to set up an exception.The monitor serial number (SN) is the device’s MAC address, formatted without colons. Example: Serial number shown on device / dashboard: abcdefghijkl ; corresponding MAC address: ab:cd:ef:gh:ij:kl “Allow only approved devices” settings Still not working? Power-cycle the router Reset the device’s Wi-Fi configuration and try again Move the device closer to the router during setup Power cycle the monitor itself. Reflash the device firmware. Contact us via the Support Form or email support@airgradient.com Running the AirGradient ONE in Offline Mode Offline mode allows the AirGradient ONE to operate without connecting to Wi-Fi. Sensor readings remain active and visible on the display. No data is sent to the AirGradient dashboard while running in offline mode. How to enable Offline Mode Locate the BOOT button On the back of the monitor, next to the USB connector, there is a small hole. Inside is the BOOT button that can be pressed using a small screwdriver or pin.   Power on / power cycle the monitor if it was already on. Wait for the prompt During startup, the display will show the message: “Press now for offline mode” Press the BOOT button Press the BOOT button through the hole while this message is shown. Confirm Offline Mode If successful, the display will show: “Offline mode = true” The monitor will now run fully offline. The display will have an airplane mode icon: Switching back to Online Mode To return the monitor to normal (online) operation: Repeat the same steps above When prompted, press the button again during startup The display will confirm that offline mode is disabled with the message: “Offline mode = false” and the airplane icon will disappear. Know Your AirGradient ONE What parameters does the AirGradient ONE measure? This page explains what each parameter means, why it is measured that way, and how frequently data is recorded. For a more detailed list refer to: https://github.com/airgradienthq/arduino/blob/master/docs/local-server.md Time Resolution Wi-Fi model: 1-minute intervals Cellular model: 3-minute intervals Particulate Matter (PM) PM2.5 (µg/m³) – Raw (cf_atm) Description: Raw, uncorrected mass concentration of airborne particles ≤ 2.5 µm. Why µg/m³? Micrograms per cubic meter represents the total mass of inhalable particles in a given air volume. This is the global standard used in air quality regulations and guidelines. PM2.5 (µg/m³) – Corrected Description: PM2.5 value adjusted using the calibration formula selected in the dashboard. Why corrected? Calibration formulas compensate for sensor characteristics and environmental factors to improve real-world accuracy. PM1 (µg/m³) Description: Mass concentration of particles ≤ 1 µm. Why µg/m³? Provides a mass-based measure of very fine particles, which can penetrate deeply into the lungs. PM10 (µg/m³) Description: Mass concentration of particles ≤ 10 µm. Why µg/m³? Indicates larger respirable particles such as dust. Note: Optical sensors are optimized for PM2.5. PM10 values are less reliable. Very large particles (e.g., pollen >10 µm) are generally not detected. PM 0.3 µm Particle Count (per dL) Description: Number of particles ≥ 0.3 µm, measured as number concentration. Why particle count? Particle count tracks the number of particles regardless of mass. Small particles may be high in number but low in weight, so count-based metrics can reveal events mass-based PM values may miss. Other extended Particle Count measures available on request: Particle count 0.5µm per dL Particle count 1.0µm per dL Particle count 2.5µm per dL Particle count 5.0µm per dL  Particle count 10µm per dL Carbon Dioxide (CO₂) CO₂ (ppm) – Raw Description: Measured carbon dioxide concentration. Why ppm? Parts per million reflects volumetric gas concentration and is the standard unit for tracking indoor CO₂ buildup from human activity. Temperature & Humidity Temperature (°C) – Raw Description: Ambient temperature near the sensor. Why °C? Direct physical measurement affecting comfort and sensor performance. Indoor monitors: Raw temperature closely reflects room conditions. Outdoor monitors: Raw temperature may diverge from true ambient because the sensor sits inside the enclosure. Corrected values compensate for this. Temperature (°C) – Corrected Description: Temperature adjusted using a calibration formula. Why corrected? Improves ambient accuracy, especially for outdoor units. Humidity (%) – Raw Description: Ambient relative humidity near the sensor. Why % RH? Relative humidity expresses water vapor content relative to saturation. It influences comfort, condensation, and sensor behavior. Outdoor monitors: Raw values may diverge due to enclosure effects; corrected values compensate for this. Humidity (%) – Corrected Description: Relative humidity adjusted using a calibration formula. Why corrected? Improves ambient accuracy for outdoor deployments. Heat Index (°C) Description: Calculated apparent temperature combining corrected temperature and humidity. Why calculated? Reflects how hot it actually feels when humidity is considered. VOC (Volatile Organic Compounds) TVOC (ppb) Description: Total VOC concentration converted to ppb using Sensirion’s formula. Why ppb? Reported in parts per billion for familiarity, but this is a relative estimate derived from the VOC index — not an absolute concentration. TVOC Index (1–500) Description: Scaled index representing total VOC activity. 100 = baseline >100 = more VOCs than recent 24-hour baseline <100 = fewer VOCs than baseline Why an index? MOx sensors respond broadly to many VOCs. Exact ppb estimates are unreliable, so a unitless index is better for detecting trends. Adaptive behavior: In clean air → becomes more sensitive to small changes In polluted air → reduces sensitivity to avoid saturation TVOC Raw log(R) Description: Logarithmic raw resistance output from the MOx sensor. Why log(R)? MOx sensors measure resistance changes of a heated metal oxide surface. Reducing gases (VOCs) → decrease resistance Oxidizing gases → increase resistance Output is broadband and non-specific. NOx (Nitrogen Oxides) NOx Index (1–500) Description: Scaled index representing oxidizing gas activity. 1 = baseline >1 = increased oxidizing gases Why an index? Similar to VOC, MOx sensors detect general oxidizing gases rather than specific compounds. Note: The NOx index does not use adaptive gain like the VOC Index NOx Raw log(R) Description: Logarithmic raw resistance from the NOx MOx sensor. Why log(R)? Resistance increases in presence of oxidizing gases such as NOx. Output reflects general oxidizing gas presence rather than specific concentrations.   What are the technical specifications of each sensor in the AirGradient ONE? PM: Plantower PMS5003 Plantower PMS5003 (laser scattering principle). Accuracy Fully Assembled & Tested Model (I-9PSL-DE_asd): Accuracy PM2.5: ±4μg/m³@0-100μg/m³, ±8%@100-500μg/m³. Accuracy Kit Version (I-9PSL-DE_kit): Accuracy PM2.5: ±10μg/m³@0-100μg/m³, ±10%@100-500μg/m³. (PM1 and PM10 are also measured but PM2.5 has the highest accuracy). VOC/NOx: Sensirion SGP41 Accuracy: TVOC <±15 @ 0 to 500 VOC Index (also available in ppb); NOX <±50 @ 0 - 500 NOX Index CO2: SenseAir S8 or SenseAir S88   SenseAir S8 (NDIR). 0 to 10000ppm. Accuracy: ±40 ppm ±3% of reading at 5 to 30°C, 0-85% RH (400 - 2000ppm range) or SenseAir S88 (NDIR). 0 to 10000ppm. Accuracy: ±40 ppm ±3% of reading at 5 to 30°C, 0-85% RH (400 - 3000ppm range) Temperature and Humidity: Sensirion SHT4X Sensirion SHT40. Accuracy: Temperature ±0.2°C @ -40 to + 125°C; Humidity ±2% RH @ 0 - 100% RH   What’s inside the AirGradient ONE? Here’s a quick overview of the main parts inside the device: See this assembly video, for more insight:  Assembling the AirGradient ONE Kit 1. AirGradient ONE Mainboard The mainboard includes: An ESP32-C3-MINI microcontroller that handles processing, Wi-Fi connectivity, and data transmission Connectors and pin sockets for all sensor modules Power management and onboard circuitry This board coordinates sensor readings and sends data to the AirGradient dashboard or your own integrations. 2. RGB LED Bar The pre-mounted 11 RGB LEDs display air quality/device status. It can be switched off. 3. 1.3" OLED Display (128x64px) The pre-mounted 1.3" OLED display with 128x64px resolution displays real-time air quality measurements and device status. It can be switched off. 4. Plantower PMS5003 PM Sensor This pre-mounted sensor measures: PM1 PM2.5 PM10 5. SenseAir S8 / S88 CO₂ Sensor Module This NDIR (Non-Dispersive Infrared) sensor measures carbon dioxide (CO₂) levels. 6. Sensirion SGP41 TVOC / NOx Sensor Module This sensor measures: TVOC (Total Volatile Organic Compounds) NOx (Nitrogen Oxides index) 7. Sensirion SHT40 Temperature & Humidity Sensor Module This sensor measures: Temperature Relative humidity Modular by Design One of the key advantages of the AirGradient ONE is its modular design. This means: Sensors can be replaced individually if needed Maintenance is easier Future upgrades are simpler This open and repairable approach helps extend the life of the monitor and supports long-term reliability.   Where can I find the Serial Number of AirGradient ONE? The method depends on whether you have a fully assembled unit or a DIY kit . Fully Assembled Devices For fully assembled units, it’s simple: The serial number (SN) is printed on the back of the device The model name (e.g. ONE, Open Air) is also indicated there DIY Kits Since DIY kits are assembled by you, the serial number is not printed on a case. There are a few ways to find it: Method 1: On the device display If the device is not connected to WiFi, the serial number will be part of the WiFi hotspot name shown on the display on startup: The format it is displayed in is: airgradient- The serial number appears after  airgradient- If your device is already connected to WiFi Reboot the device Wait for startup The serial number will briefly appear on the screen Tip: Use your phone camera to capture the SN quickly. Method 2: Via Wi-Fi hotspot Reset the WiFi credentials on your ONE: https://www.airgradient.com/documentation/kb/one-resetting-wifi Open the Wi-Fi settings on your phone or computer. Look for a network named: airgradient- The serial number appears after  airgradient- . On some phones, the SN may be truncated due to display size limitations, in that case, continue following the steps below. Connect to this Wi-Fi network, password: cleanair Once connected, either: Wait for the Wi-Fi portal to open automatically, or Manually go to  192.168.4.1  in your browser The full serial number will be displayed in the portal. Note it down. Method 3: Via Device Logs Connect your AirGradient Open Air to your computer using a USB cable. Open Google Chrome or Microsoft Edge (or any Chromium based browser) Go to: https://www.airgradient.com/documentation/kb/kb-diy-online-debug Click the  “Debug Now”  button. In the pop-up window: Select the device labeled  “USB JTAG/Serial debug unit…” Click  “Connect” When prompted, select  “Logs & Console”   A log window (black background) will appear. Click the  “Reset Device”  button at the bottom right. The device will reboot, and logs will start appearing. Look for the line containing: Serial nr: The value shown after this is your device’s serial number. You can use Ctrl + F to quickly find it. Note it down. What do the LED indicators mean? Which parameter are they based on? The AirGradient ONE has a row of 11 LEDs behind the plastic at the top of the device. These LEDs convey important information to the user - namely, monitor status and pollutant concentrations. They can be split into two groups. Top-left LED: This is a single LED in the device’s top-left corner. It is typically off but will turn on when the monitor encounters an issue. LED bar (beginning in the top-right corner): This bar of nine LEDs starts at the top-right corner of the device and moves left. The more LEDs that turn on, the worse the air quality is. It’s worth noting that despite the device having 11 LEDs, only 10 will turn on at any given time (up to nine for pollutant concentration and one separate LED for monitor status). However, most of the time, you will only see a few LEDs on the device. Let’s discuss how you can interpret the LEDs across the top of your AirGradient ONE. Pollutant LEDs These are the LEDs that start at the top-right corner of the device and spread to the left as the air quality deteriorates. By default, these LEDs show PM2.5 concentration in accordance with the key in the image below. As you can see, when the air quality is good, you should expect to see only one or two LEDs at the top-right of the device. These will both be green. As the air quality worsens, the LEDs will spread further left and they will change to yellow, followed by orange, red and purple to indicate bad air quality Under the device settings on your dashboard, you can also change the LEDs to instead show carbon dioxide concentrations. They follow the same system, and you can find the full key in the image below. Currently, these LEDs can only be set to show either PM2.5 or CO2 concentration. Status LEDs While the single LED in the top-left corner should remain off most of the time, you may sometimes see it turn either red, yellow, or purple. These LEDs do not have any correlation to the air quality, and instead indicate monitor errors. Red: Connection to WI-FI network failed. This may be due to incorrect credentials or unsupported encryption. Yellow: Connected to WI-FI network but the server can not be reached through the Internet, e.g. blocked by firewall. Purple: Server is reachable but there is some configuration issue to be fixed on the server side. If the LED turns purple, it is likely an issue on our side and there is nothing you need to do.  Connection will be restored as soon as our developers have had time to identify and fix the issue. If the LED is either red or yellow, you may need to change your Wi-Fi settings or connect to a different network. LED Test When the device is first booted, or as requested through Home Assistant or the web dashboard, an LED test can be performed. This test will light all of the LEDs so the user can ensure they are working. This is the only time (with normal firmware) that all eleven LEDs will turn on.   Can the AirGradient ONE be used outdoors? It is not recommended to use the AirGradient ONE outdoors. The enclosure is designed for indoor use with multiple mounting options: attachable clip-on stands for desktops, or wall mounts that perfectly fit typical US and EU junction boxes with a discreet cable management design. To ensure accurate temperature and humidity measurements, the AirGradient ONE features a dedicated sensor that is physically isolated from other mainboard components to prevent interference from the heat they generate. For outdoor use, the AirGradient Open Air is recommended. It is specifically designed with a robust, weather-proof enclosure and wall or pole mounting options, ensuring convenient outdoor installation and readiness for exposure to the elements.   Control the LEDs and Display on the AirGradient ONE This guide walks you through all the LED and display settings available on your AirGradient ONE, so you can tailor it to your environment and preferences. 1) Enable Advanced Configuration Settings Before anything else, you need to unlock the LED & Display controls. Go to General Settings Scroll down Enable Show Advanced Configuration Settings Click Save Once enabled, a new “LED & Display” tab will appear in General Settings. 2) Open the LED & Display Tab Here’s what you’ll see: LED Mode This controls what parameter the LED strip represents. Or turn it off completely. LEDs off LEDs on CO2 levels:  Best for ventilation awareness LEDs on PM2.5 levels: Better if you care about particulates Pick one based on what matters more to you. You can’t show both at the same time as there's only one LED strip. CO₂ Configuration This only applies if LEDs are set to CO2 mode. You define when the LED color changes: Green → Amber (slightly elevated CO2) Amber → Red (high CO2) Default Values: LED turns Amber at 1000 ppm LED turns Red at 2000 ppm You can also set the level where all LEDs turn red . Day & Night Time This sets when the device switches between “day mode” and “night mode”. Default Values Day Start - 08:00 Day End - 20:00 These times control how brightness behaves in the next settings. LED Brightness You can set different brightness levels for: Day Time (as set in Day & Night Time above) Night Time  (as set in Day & Night Time above)  Typical setup: Day: brighter (visible across the room) Night: dim or almost off (avoid disturbance) Display Brightness Same idea as LEDs, but for the screen. Set brightness for day Set brightness for night Auto Screen Off (2am–3am) This settings helps extend display lifespan. Notes These features require firmware version 3.1.1 or higher You can click “Apply to All Locations” if you manage multiple devices Changes will apply with 1-5 minutes after saving.