Map Start-up Guide

Introduction

The PurpleAir map is a web application that displays a network of community-owned, PurpleAir sensors. Each sensor uploads data to the PurpleAir map in real time. Click or tap on a Map Marker on the map to view current sensor information. The map Configuration Menu :configuration_menu:, found in the upper left corner of the map, enables users to customize the information they want to see on the PurpleAir map.

In addition to a web browser, you may access the PurpleAir map from our progressive web app (PWA). This can be installed from Google Chrome. On your computer, at the top right of the address bar, click Install :install:. On your Android device, click or tap Install. Google offers a support page to use progressive web apps.

Map Marker

Click or tap a Map Marker, represented as a colored dot, to present a pop-up window which displays various sensor data. The creation date and time of this data is displayed first at the top of this window. Inside sensors are identified by having a black border around the marker. Outside sensors are identified by having no border.

Next is the Graph Averages and Data Layer information. The defaults of “10-minute” and “US EPA PM2.5 AQI”, respectively, will state the AQI value as a prominent number on the right, and the phrase “10 Minute Average US EPA PM2.5 AQI is now” to the left of the AQI value.

Continuing below the AQI, the current range the AQI value is among, and the description of that range is presented.

Next, seven averages are provided; “Now”, “10 Min”, “30 Min”, “1 hr”, “6 hr”, “1 Day”, and “1 Week”.

The name given to the sensor during registration is listed below the afore mentioned averages. If the sensor is the PA-I-Indoor model, an icon of a house will display to the left of the sensor name.

The PurpleAirWidget is located below the sensor name. This widget displays the sensor temperature, laser counter channel (followed by confidence if two channels are present), the type or model, firmware version, and WiFi signal strength. This is followed by a link to “Get This Widget”.

Finally, at the bottom of the pop-up window, you are invited to join the community of citizen scientists. A link is provided to purchase a similar sensor.

Search Box

The search box is located at the top right corner of the PurpleAir map. Search by address, city, or ZIP code to zoom-in on that area. You can also search by the specific name of a sensor in the current map view.

PA_Map_Search

Data Collection

You can easily download historical data from PurpleAir sensors. There are a few ways to do so. Continue here for the Data Collection guide.

Bookmark

You can create a bookmark in your web browser using the URL of the current map view, or a currently selected sensor marker. This would enable you to visit the bookmark to see your sensor(s) at any time without searching the map. Adding that same view to the home screen of your phone or tablet creates an app-type icon; this provides another way to stay informed of sensor readings in spaces that impact or interest you.

A quick how-to was created by lifehacker.

To create a successful bookmark for a sensor registered as Private, access this sensor via the “visible on the map” link in your registration confirmation email.

View Your Sensors on the Map

You may view your personal sensor(s) on the PurpleAir map. There are a few ways to do so. Regardless of the registration of your sensor as Public or Private, you will discover how to access it on the map within this section.

You may view your public sensor on the map by geographically locating your Map Marker on the PurpleAir map.

You can more directly present your sensor from a link. It is not required to login to the map to do so. You can easily see it by using the “visible on the map” link in your registration confirmation email. This link is a private access point to you.

If instead you wish to utilize the “Show My Sensors" feature, you would need to first register your sensor using a Gmail account as the Owner’s Email. Then you’ll log into the PurpleAir map from the top menu using that same Gmail address. To exclude all sensors other than any that you own, simply uncheck “Outside Sensors” and “Inside Sensors” while keeping ​"Show My Sensors" checked in the map Configuration Menu.

Private Sensor

Your sensors that had been registered as Private are accessible via the previously mentioned private methods. They are specified below.

First, you can access them by utilizing the “visible on the map” link in your registration confirmation email. Again, this link is a private access point to you.

Lastly, you may utilize the “Show My Sensors" feature while logged-in to the PurpleAir map. See ‘View Your Sensors on the Map’ above for details.

Customize

A powerful characteristic of the PurpleAir network of sensors can be utilized via the Configuration Menu :configuration_menu:. The information conveyed from the PurpleAir map can be customized in many ways. The variety of customizations include the subtleties among conventional standards, the apparent different consequences of pollutants, and non-pollutant data like temperature, humidity, and pressure.

PA_Map_ConfigurationMenu

The following fields are found within the Configuration Menu :configuration_menu: to customize what sensors convey.

Data Layers

The “Data Layer“ field determines which indices, scales, or metadata to display on the Map Markers, graphs, and the map legend. The default field-selection is “US EPA PM2.5 AQI“.

The following data layers are available to view on the PurpleAir map. Hover over a legend on the map to see messages about each of its values.

Air Quality Index

This first partition of data layers is a section of Air Quality Indices (AQIs). Data for the AQIs are supplied by the laser counters within the PurpleAir sensors. Choose a data layer from Air Quality Index Layers to present the sensor data within the standard index.

Visibility Data

This next partition of data layers is a section of visibility indices. Data for the indices are supplied by the laser counters within the PurpleAir sensors. Choose a data layer from Visibility Data Layers to present the sensor data within the standard index.

Environmental Data

This next partition of data layers is a section of miscellaneous secondary and derivative data that describe the environment in ways other than pollutants. Data for this section are supplied by auxiliary units within the PurpleAir sensors. Choose a data layer from Environmental Data Layers to present the sensor data within the standard scale.

Raw Sensor Data

This next partition of data layers is a section of direct data that has not been translated for any particular index or general use. Data for this section are supplied by the laser counter(s) and auxiliary units within the PurpleAir sensors. Choose a data layer from Data Layer Partition: Raw Data to present the sensor data within the standard scale.

Sensor Metadata

This last partition of data layers is a section of miscellaneous system-function data. Data for this section are supplied by system functions within the PurpleAir sensors. Choose a data layer from Sensor Metadata Layers to present the sensor data within the standard scale.

Apply Conversion

The “Apply conversion“ field determines which conversion factor to apply to the raw sensor data. The default field-selection is “no“. Conversions help accommodate different types of pollution with different particle densities. Conversion may be needed when inferring the mass of any combination of particulates derived from particle counts.

PurpleAir enables the visitor of the map to obtain comparable results to data reported by regulatory sensors by offering conversion factors.

To better understand conversion factors, let’s consider that airborne particles from dust, smoke, and other organic and inorganic sources can be the same size, but have different densities. For example, \text{PM}_{2.5} from wildfire smoke will have a different density than \text{PM}_{2.5} from dust blowing off of a gravel pit.

PurpleAir Sensors first measure the particle count and size. Then, it infers an average particle density.

If, for example the predominant source of \text{PM}_{2.5} is from wildfire smoke, which has a lower density than the assumed density used by the sensor, the sensor data will predictably overestimate the mass concentration and read higher than the regulatory monitor. Conversely, if the predominant source of \text{PM}_{2.5} was a more dense material like gravel dust, the sensor data would predictably underestimate the mass concentration and read lower than the regulatory monitors (such as those used to report to AirNow.gov, Weather Underground, etc.).

According to a recent study published by researchers in Australia, the AQ&U conversion factor has proven very effective in wildfire smoke. Another example developed by Oregon’s Lane Regional Air Protection Agency, the LRAPA conversion factor is very effective for their particular area during a smoke event caused by wildfires. Based on their study, the EPA has developed their own conversion factor for wildfire conditions.

Continue here for the “Apply conversion” field options.

Averaging Period

The “Averaging period” field determines the moving average of the two-minute data reports over the specified time period. These moving averages are displayed on Map Markers and graphs. The default field-selection is “10-minute”.

Real-time: This field selection reports the data as they become available from the sensor in two minute intervals.

10-minute: This default field-selection derives a moving average of the sensor data within the last ten minutes.

30-minute: This field selection derives a moving average of the sensor data within the last thirty minutes.

1-hour: This field selection derives a moving average of the sensor data within the last hour.

6-hour: This field selection derives a moving average of the sensor data within the last six hours.

1-day: This field selection derives a moving average of the sensor data within the last day.

1-week: This field selection derives a moving average of the sensor data within the last week.

Base Map Type

The “Base map type” field selection determines the aesthetics of the spacial information the map conveys; the background of the Map Markers. The default field-selection is “detailed”.

Detailed: This default field-selection is the PurpleAir-customized Mapbox map that provides an elegant display of common boundaries, like zoning and vegetation.

Basic: This field selection uses MapTiler Basic, the perfect lightweight and informative map for overlaying the sensor data.

Satellite: This field selection uses Mapbox Satellite for a full global, image based map that is perfect as a blank canvas for the sensor data.

Topographic: This field selection uses Mapbox Outdoors for a general-purpose map with curated tile sets and specialized styling tailored to hiking, biking, and the most adventurous use cases.

Dark: This field selection uses Mapbox Dark, a subtle, full-featured map designed to provide geographic context while highlighting the data of the sensors.

Show…

The checkboxes for “Show outside, Inside, and my sensors” enable the explicit inclusion of whether a sensor was registered outside, inside, or to a logged-in owner. All checkboxes are selected by default.

Show Outside: Select this checkbox to enable showing “outside” sensors. Outside sensors are identified by having no border.

Show Inside: Select this checkbox to enable showing “inside” sensors. Inside sensors are identified by having a black border around the marker.

Show My Sensors: Select this checkbox to enable showing “my” sensors. These are sensors that were registered with an owner email that matches the logged-in email. This will also include sensors registered as private with the owner email matching the logged-in email.

Reporting or Modified Within

The “Reporting or modified within” field limits the Map Markers displayed to only the sensors that have made contact with PurpleAir servers within the selected time period. The default field-selection is “7 days”.

10 Minutes: This field selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last ten minutes.

30 Minutes: This field selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last thirty minutes.

1 Hour: This field selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last sixty minutes.

1 Day: This field selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last twenty-four hours.

7 Days: This default field-selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last seven days.

30 Days: This field selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last thirty days.

90 Days: This field selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last ninety days.

1 Year: This field selection determines the Map Markers displayed include only those PurpleAir sensors that have communicated with PurpleAir servers within the last year.

All Time: This field selection determines the Map Markers displayed include all sensors that have communicated to the PurpleAir servers at any time.

Show Averages as Rings

The “Show averages as rings” field toggles the inclusion of compact information displayed around the Map Markers. The default for this checkbox is not selected.

When available, this option adds rings around each Map Marker. Each ring shows the color that represents an average’s value. Starting from the selected average in the center of the marker, each ring corresponds to the next longer average as they progress outward.