Startup Guide for PurpleAir Sensors

Getting started with PurpleAir sensor WiFi configuration, registration, and installation.

Before you begin

Before connecting your sensor to WiFi, please ensure you are connecting to the right type of network. PurpleAir sensors only support 2.4Ghz WiFi networks. They will need special authorization from the network administrator to allow them to communicate on captive portal networks, such as those used by coffee shops, universities, etc. PurpleAir sensors do not support WPA2-Enterprise networks at this time. Supported networks types are WPA and WPA2-PSK (Pre-Shared Key). WPA2-PSK is the most common type of WiFi network.

We recommend configuring WiFi on your sensor indoors, near your computer or where you have a good WiFi signal. You should also check that there is a reasonable WiFi signal where you intend to mount the sensor. This can be done by browsing the internet using WiFi with a phone or computer near the desired location.

PurpleAir PA-II or PA-II-SD Sensor

In the box

  • Sensor
  • Outdoor power supply
  • Optional mounting screw (1 per sensor)
  • Optional mounting zip ties (3 per sensor includes spares)

Powering your sensor

  1. Plug the Micro USB end of the power supply into the base of the sensor.
  2. Plug the power supply into a functioning wall outlet.
  3. Look for a very dim red glow up inside the sensor housing to confirm the sensor is receiving power. (You may have to cup your hands around the sensor and peer inside to see it.)

PurpleAir PA-I-Indoor Sensor

In the box

  • Sensor
  • USB power block

Powering your sensor

  1. Plug the USB cable into the power block.
  2. Plug the power block into a functioning wall outlet.
  3. A blue light seen from the top of the sensor indicates the sensor is starting and will begin to glow the current AQI color shortly.

Connecting your sensor to WiFi

The WiFi configuration process is the same for all PurpleAir sensors.

  1. It’s best to configure your sensor to WiFi with the router, computer/phone/tablet, and sensor in the same room. After plugging in your device and confirming it is receiving power (look for the dim red glow inside the sensor housing, or for indoor sensors, make sure the device itself is glowing), on a WiFi-enabled device, open the list of available WiFi networks.
  2. Connect to the sensor's network, PurpleAir-****. The **** is a 2-4 character code determined by your sensor. (It may take up to 10 minutes after the sensor is plugged in for this network to appear.) 
  3. Depending on your operating system or device, you may get a pop-up window or a message to sign in to the network. If you receive a message to sign in to the network, press it to make the pop-up window appear. The pop-up window will list all available WiFi networks.
    Note: If the pop-up window does not appear, after making sure you've selected the "PurpleAir-****" network and waiting a bit, if you still don't get the pop-up, try opening a web browser and loading a webpage. If you are indeed connected to the PurpleAir network, this will load the sensor interface with the WiFi settings for the sensor. Another option is to open a webpage and in the address bar, enter the default IP address for the sensor:
  4. Choose the WiFi network you would like the sensor to connect to, enter the password for that network, and click Save. A hidden WiFi network can be entered by selecting the option at the bottom of the list.
  5. The WiFi status bar will turn green once your PurpleAir sensor is connected to WiFi and transmitting data. Once your device is configured to your local WiFi network, it will no longer appear in the list of available networks - the fact that it has disappeared means that the sensor is successfully configured to WiFi.

    Important: If your sensor network name is AirMonitor_****, you will need to go to to configure WiFi on your sensor.

Registering your sensor on the PurpleAir map

Registering your sensor places a map marker on the PurpleAir map. You will only need to do this once. If you would like to change any registration details, please complete the registration form again. You will need to use the same "Owner's Email" that was used in the first registration to make changes.

  1. Go to
  2. Enter the sensor's Device-ID exactly as printed on the sensor's label.
  3. Enter the associated email address, which is usually the email that was used to purchase the sensor. If you do not know the correct email address, please contact us for help or to associate a new email address. PurpleAir will need the Device-ID in order to help you.
  4. Complete the rest of the registration form. For additional help, you can view a full explanation of registration fields or read our registration tips below.
  5. Click register and look for a green "successful registration" notice. A registration confirmation email is sent to the Associated Email and Owner's Email. This email includes a link to view your sensor on the PurpleAir map.

Tips on completing the registration form

  • When choosing a location, enter the location you would like the map marker to appear on the PurpleAir map.
    Tip: Zoom in as much as possible and drag the red icon on the map to achieve the most precise location of the map marker on the PurpleAir map.
  • When entering the sensor owner's information, this should be the person who is hosting the sensor on their WiFi network. The sensor owner may receive notifications regarding sensor status or other important information about maintaining the sensor.
  • If you set your sensor to private, you may view it by logging in to the PurpleAir map using a Gmail address that matches the Owner's Email in the registration form. Alternatively, you can use the link provided in the registration confirmation email. You may share this link with family and friends.
  • After a successful registration, it only takes a few minutes for the sensor to appear on the map.
  • Please note: you are not required to log in to the map to see your sensor(s). You can easily see your sensor(s) by using the "visible on the map" link in your registration confirmation email. From there you can create a bookmark in your web browser using that URL, enabling you to click it to see your sensor(s) at any time without searching the map.
  • Any sensor that has not connected to a WiFi network for one week or so will not be visible on the PurpleAir map.
  • If you completed the registration form and do not see your sensor on the map or your map marker is grey (not reporting data):
    • Ensure you entered a location on the registration form by looking for the coordinates in the registration confirmation email.
    • Check the WiFi connection as per the Connecting your sensor to WiFi section above.
    • Or contact us for assistance.

Tips on PA-II and PA-II-SD installation

  • Choose a location that is convenient to reach, has access to a power outlet, and falls within range of the WiFi network.
  • If possible, mount the sensor away from vents, local sources of pollution such as BBQs, and any foliage that would increase the likelihood of insects getting inside the laser counters.
  • Install the sensor in the vertical position, with the open end facing toward the ground. The housing is designed to protect the device from the elements while allowing air to flow freely past the two laser counters.
  • Be sure to mount the sensor high enough off of any surface that would allow rain water to splash up into the underside of the sensor.
  • The power supply should be mounted so that it will not be submerged in water or covered by snow. 
  • Use either cable ties or a screw to mount the sensor and power supply, and fashion a "drip loop" to prevent water from running down the wires and into the electronics.
  • PurpleAir outdoor sensors can withstand direct sun without being damaged. Mounting the sensor in a shady spot will produce temperature readings that are not affected by direct sunlight.
    Please note that temperature readings are already elevated by as much as 10 degrees Fahrenheit due to heat generated by the WiFi module inside the sensor.
  • Connect the power supply to a power outlet and tuck the wires away.

Tips on PA-I-Indoor installation

  • The sensor is designed to lay flat on a hard surface like a counter top or desk.
  • Place the sensor in a central location - away from air vents, humidifiers, and cooking areas - to gather an average reading, or in an area of interest to monitor specific activity.