This guide introduces the PurpleAir map and helps you navigate its features with confidence. Whether you’re just getting started or need a quick refresher, it’s here to support your understanding.
What You See on the Map
Map Markers
Each sensor is displayed as a colored dot, known as a map marker. The number inside the marker represents the current value from the data layer you’ve selected. Click or tap a marker to view more information about that sensor.
The number appears in either black or white to maintain contrast against the marker’s background color. This color shift is purely for readability; it does not indicate any change in the data or sensor status.
Indoor vs Outdoor Sensors
When viewing the PurpleAir map, sensor icons provide quick visual cues to distinguish their type and status:
-
Black Outline: Indicates an indoor sensor.
-
No Outline: Indicates an outdoor sensor.
-
Gray Icon: The sensor is offline or has stopped reporting data.
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 multiple sensors are registered to the exact same location, only one will be visible and clickable. To avoid this, slightly adjust the location of each sensor during registration.
Transparent Sensors
Some markers appear partially transparent. This visual cue shows the confidence level of the sensor. Outdoor-rated PurpleAir sensors contain two data channels. When both agree, the marker appears solid. If they diverge, the marker becomes more transparent. Indoor-only models like the PurpleAir Touch use a single laser counter and always display with transparency.
Currently Selected Scale
Located at the bottom-left corner of the map, you can find the scale for the currently selected data layer. Hovering over each breakpoint shows you a description of that range.
Displayed Map Settings
The box at the top-left of the map interface displays your active data layer, averaging period, and conversion (if one is applied). This quickly lets you know which major map configurations you have active, without having to go into the menu.
Search Function
The magnifying glass icon at the top-right corner of the map can be used to search for locations or sensor names. Sensor name searches are limited to those currently visible on the map.
Customizing Your Map View
To adjust how the map looks or what data it shows, open the configuration menu by clicking the gear icon.
Map Settings
You can change your map settings by clicking on the gear icon in the top-left box. The following is a list of settings and their descriptions:
Data Layer
The Data Layer setting lets you change what type of data you’re looking at. The options include particulate matter data, like the US EPA AQI, or Raw PM2.5, to environmental data like Temperature or Humidity.
Conversions
The Apply Conversion setting lets you apply a conversion to the data you’re looking at. Conversions are used to account for different environmental conditions, such as if you’re in a specific region or are inundated with wildfire smoke.
Averaging Period
The Averaging Period setting affects the historical average of the data you’re viewing. The default is a 10-minute average, but you can select shorter options like real-time or longer averaging periods for broader trend analysis.
Base Map Type
The Base Map Type setting affects the visual style of the map you’re viewing (for example, satellite or standard map view).
Accessible Colors
The Accessible Colors setting enables an alternative color palette designed to improve visibility for users with visual impairments.
Gradient Colors
The Gradient Colors setting causes map markers to blend smoothly through a scale’s color range, instead of changing abruptly when moving between defined breakpoints.
Sensor Filtering
The Sensor Filtering checkboxes let you toggle indoor sensors, outdoor sensors, or your own sensors on or off.
Reporting or Modified Within
The Reporting or Modified Within setting allows you to hide sensors based on how recently they have reported data.
Averages as Rings
The Averages as Rings setting displays recent historical averages as rings surrounding each sensor marker.
Place Names on Top
The Place Names on Top setting places geographic labels (such as city or country names) above map markers.
Preferred Units
The Preferred Units setting lets you choose between the Metric and Imperial measurement systems.
Mobile Version
While we don’t have a PurpleAir app just yet, the PurpleAir map can be added to the home screen on a mobile device as a Progressive Web App (PWA). 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?.
Saving Your Map Settings
Your chosen map settings are stored in the map’s URL. So if you want to save your map settings, you can bookmark the page or copy the URL and save it elsewhere. Please note that all cookies are accepted by default when you “Accept Cookies." If you click “Customize Cookies”, you can select which types of cookies will be saved. “Necessary” must always be checked.
Viewing Private Sensors on the Map
There are two methods you can use to see private sensors on the map.
-
You can use the map link that you receive after registering the sensor, which you set during registration.
-
You can set the owner’s email to a Google-associated email in sensor registration. Then, you can log into the map with your Google account by clicking on the icon that looks like a person at the top right of the map, then logging in with the same email that you set as the owner’s email. Once logged in, you’ll be able to see any private sensors with that owner’s email as long as the My Sensors checkbox is checked under sensor filtering.
Turning this off will hide your registered sensors from view.
Exploring Sensor Data
Sensor Pop-up
Clicking a sensor’s map marker opens a popup window with details including its current value, confidence score, name, and more.
What it shows, in order:
-
Date and time
-
Current map settings
-
Current value
-
Description of scale level
-
Recent averages
-
Sensor name
-
Status indicators:
-
SD card
-
Environmental sensor board
-
Channels A and B
-
Confidence score
-
Model and firmware version
Viewing Graphs
Clicking on a sensor’s map marker also opens a graph of its recent data in addition to the pop-up window. On this graph, you can:
-
View recent data with timestamps.
-
View channel-specific data.
-
Click-and-drag to zoom into specific date ranges
-
Click on other sensors to overlay data from multiple sensors.
Longer averages (like 1-day) display more history, up to a year. Some averages (e.g., 1-month, 1-year) are only available in graph views and are marked with an asterisk (*) where applicable.
\
Comprehensive information on using the map graph can be found here: How to Use the Map Graph
Downloading Sensor Data
The data you see on the map is directly available for download in graph or CSV format. Data you download this way will be saved with your local timezone. The downloaded files do not specify a timezone. Learn how to download map data here: Q: How Do I Download Map Graph Data
