This guide serves as a starting point for using the PurpleAir Map. In it, you’ll information regarding using and interpreting the map.
Map Marker
Every PurpleAir sensor on the PurpleAir map will appear as a colored dot. We call these map markers. Every map marker contains a numerical value that reflects whichever data layer you have selected. Clicking or tapping on a map marker will open a popup window with details about the selected sensor.
The color of these numbers can be black or white depending on the map marker color. This feature is meant to improve map readability.
Indoor vs Outdoor
Map markers with a black outline represent indoor sensors, while markers without this outline represent outdoor sensors. Sensors that are not actively reporting to the PurpleAir map will appear gray.
Overlapping Sensors
It is possible that two sensors’ registered locations are extremely close to one another, causing the map markers to overlap. To view these sensors, try zooming in very close.
If two or more sensors are registered with the exact same longitude and latitude, you will not be able to see more than one on the map or click on more than one. We recommend registering multiple devices that are in the same location with slightly different locations.
Transparent Sensors
Some sensors on the map may appear slightly transparent. This is to indicate the level of confidence in the sensor’s readings.
All outdoor capable PurpleAir sensors have two laser counters. They have a confidence score which is a measure of how closely these two laser counters are reading. The higher the confidence score, the more confident you can feel in a sensor’s reports. The lower the confidence score, the more transparent the sensor will appear as on the map.
PurpleAir Touch devices have one laser counter, and thus are shown as transparent by default. This is because there is no other source of information to compare against.
Search Box
The search box is located at the top-right corner of the PurpleAir map. You can search by an address, zip code, or sensor name. The sensor name search will only work if that sensor is in the current map view.
View Your Sensors on the Map
If you have sensors that are registered to the PurpleAir map, you can view them by following the steps listed in the following article: View Your Sensor on the Map.
Configuration Menu
Many settings are available on the PurpleAir map through the configuration menu. To access the configuration menu, click on the box with a gear 
icon.
When expanded, the full configuration menu looks like this:
Information on each of the different settings is found below.
Map Settings
Data Layer
The “Data Layer” field will change the data displayed by the map markers on the PurpleAir map. The options in the drop-down menu are sorted into different categories: Air Quality Standards, Air Quality, Visibility, Environment, and Metadata. The default selection is US EPA PM2.5 AQI.
Apply Conversion
The “Apply Conversion” field is used to select a conversion factor to apply to the data. This is only available when an Air Quality Index (AQI) is selected in the “Data Layer” field. By default, the “No” option is selected.
Averaging Period
PurpleAir sensors send data to our servers every two minutes. However, this data can be averaged to see trends over a long period of time. The “Averaging Period” field is used to set the average of data displayed on the PurpleAir map. “10-minute” is the default option.
Base Map Type
The “Base Map Type” field is used to change the look of the map. The default selection is “Detailed.”
Use Accessible Colors When Available
The “Use Accessible Colors When Available” option can be toggled on to change the map marker colors to help those with accessibility needs. Accessible colors are not available for every data layer.
Show Outside/Inside/My Sensors
The checkboxes next to the words “outside,” “inside,” and “my sensors” are used to filter what sensors appear on the PurpleAir map. If a checkbox is checked, the matching sensors will be displayed.
The “my sensors” option will display sensors that are connected to the email address logged into the PurpleAir map. This is only available for Google associated email addresses. More information is available here: View Your Sensor on the Map.
By default, all three of these checkboxes are enabled.
Show Sensors Reporting or Modified Within
The “Show Sensors Reporting or Modified Within” field filters out map markers that have not reported to our servers or been modified within the specified amount of time. To filter out gray dots on the map, change the setting to a shorter time-span. The default option is “7 days.”
Show Averages as Rings
The “Show Averages as Rings” option will display thin rings around each sensor representing its previous averages. Starting from the selected average in the “Averaging Period” field in the center of each map marker, each ring corresponds to the next longer average as they progress outward.
Show Place Names on Top
Names of countries, cities, roads, and more appear on the PurpleAir map as well as air quality data. The “Show Place Names on Top” option is used to choose whether or not these names should appear on top of the map markers or below. The option is enabled by default.
Save the Map Settings
Bookmarking the URL of the PurpleAir map will save the settings you currently have. Visiting this bookmark will take you to exactly the same place with the same settings every time. Lifehacker has created a quick tutorial on adding a site to the homescreen on Apple devices.
The PurpleAir map can be added to the home screen on a mobile device to create an app shortcut. This provides easy access to the PurpleAir map without having to open it in your web browser. More information is available here: Q. Does PurpleAir have an app?.
Download Data
There are several ways to download PurpleAir data. View the available options here: How do I download sensor data?
Learn More
API Landing Page
Which AQI Data Layer to Choose
Why Should I Put My Indoor Sensor On The Map?
