PurpleAir Monitor

Thank you for participating in the Clean Air Carolina AirKeepers Citizen Science program.

 

As an AirKeeper, you will contribute to a growing body of knowledge on localized air pollution. This information is crucial in determining neighborhood-level differences in air quality across North Carolina. This data will contribute to Clean Air Carolina’s goal of reducing air pollution to ensure clean air for all who live, work, and play in North Carolina.

After reviewing this manual, you will know how to:

  • Install your PurpleAir™ sensor.
  • Connect the PurpleAir™ sensor to your WiFi network.
  • Register your PurpleAir™ sensor and add it to the map.

While this manual is meant to be comprehensive, unforeseen challenges may arise with your PurpleAir™ sensor. Please call Clean Air Carolina at (704) 307-9528 if you have questions or concerns that are not covered in this document.

What Does It Measure?

What is particulate matter?

Particulate matter (PM), also known as particle pollution, is a type of air pollution composed of both liquid and solid particles. Although some particulate matter is emitted from specific sources such as forest fires or construction sites, most particulate matter is the result of complex chemical reactions between gases emitted from sources such as automobiles, industry, and power plants. While particulate matter comes in a variety of shapes and sizes, PM10 and PM2.5 are widely studied due to their harmful effect on health. PM2.5 is comprised of particles only 2.5 millionths of a meter across.

What are the health effects of particulate matter?

If inhaled, particulate matter can cause serious health effects. PM2.5  poses the greatest threat to health as it is small enough to pass deep into the lungs and enter the bloodstream. Particulate matter may cause cardiovascular problems including blood clots, lung irritation and inflammation, and aggravation of existing respiratory disease such as chronic obstructive pulmonary disease (COPD) and asthma. Children, older adults, and those with preexisting conditions are most prone to the harmful effects of particulate matter. Therefore, it is important to monitor changes in particulate matter levels in order to protect the health of vulnerable populations.

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What is PurpleAir™?

The PurpleAir™ sensor is a device that uses two laser particle counters, Channels A and B, to capture and record data about microscopic particulate matter (PM2.5) suspended in the air. It then calculates the mass of the particles in micrograms per cubic meter (µg/m³). The sensor uses WiFi connectivity to display real-time air quality readings on the PurpleAir™ Map, which is a crowdsourced map where data can be shared with scientists and the public.

PurpleAir™ comes in an enclosure that protects it from the natural elements. In addition to measuring PM2.5, this sensor also measures temperature and relative humidity.

What comes with the PurpleAir™ sensor?

When your device arrives, you will see five components:

  1. Purple Air Sensor (all hardware contained inside)
  2. Marine heat-shrink pre-joined micro USB
  3. 5V 2A outdoor power supply
  4. 33 feet of cable
  5. Mounting screws or zip ties

Tools needed to install your PurpleAir™ sensor

One (1) drill or screwdriver with Phillips head (if installing with screws)

PurpleAir™ Set-up Protocol

Instructions on how to install your PurpleAir™ sensor, configure your WiFi, and register your sensor so the data will upload to PurpleAir™ map.

Installation Tips

  1. The PurpleAir™ enclosure is designed to let air flow freely while protecting the electronics from the elements.
  2. Although the power supply is waterproof, it should be mounted so that will not be submersed in water or covered by snow.
  3. Use a drip loop with wires to prevent water from running directly down wires into the device, power supply, or power outlet.
  4. It is best to mount the sensor in a shady spot under the eve of the roof (usually the north-facing part of the house).
  5. To produce better data, it is best to mount it away from vents or anything that might affect the readings, such as a charcoal grill.
  6. The power cord is only 33 feet long, so you will need a power outlet within 33 feet of the sensor. (make sure you’re in WiFi range as well)

Installation Guide

*Note: all screenshots are meant to provide a general guideline as screens for other devices may look different.

Install your PurpleAir™ sensor

Once you have selected a location for your PurpleAir™ sensor, use a cable tie, screw, or your method of choice. Attach to the chosen location using the aluminum bracket.

Connect the power supply to an outlet and mount it away from the ground.

Route and tuck the wires away using a drip loop.

Configure WiFi

Connect your phone, tablet, or computer to a WiFi network called “AirMonitor_xxxx”. The “xxxx” is specific to your sensor.

Select your home WiFi network.

Type in your home WiFi network password.

Click “Save”.

A confirmation screen will appear on the web page with your sensor’s information.

Congratulations!

You have installed and registered your PurpleAir™ sensor. It may take a couple of days for the data from your sensor to appear on the PurpleAir™ Map.

PurpleAir™ Troubleshooting

  1. PurpleAir™ sensors will only work on 2.4GHz WiFi networks. PurpleAir™ sensors will not work on 5GHz networks.
  2. PurpleAir™ sensors will not work on networks where you access the internet by logging on to a web page (this might include public WiFi networks that require authentication)
  3. When connecting your PurpleAir™ sensor to a WiFi network, you may have to wait some time for it to connect to the network. If it doesn’t connect, try disconnecting and reconnecting your WiFi, refreshing the webpage, unplugging the router, or contacting your WiFi network provider. You may have to do this multiple times before the sensor connects to a WiFi network.
  4. Once the sensor is successfully connected to your home WiFi, make sure you switch the WiFi connected to your phone, tablet or computer back to your home WiFi. The the “AirMonitor_xxxx” will no longer appear.

SETUP ISSUES

Wifi

The Purple Air Device uses WiFi to connect to the internet and report air pollution data.  Setting up the WiFi in installation can be a tricky step, so be sure to give it a few extra tries.  Here are some common issues:

I don’t see my “AirMonitor_xxxx”

  1. The monitor might not have power.  Try plugging it in, and making sure you see a red light inside the device, or hear a small whirr from the fans.
  2. The monitor will connect to an open wifi network first, like those at coffee shops, or from public internet networks.  If it’s connected, the monitor will disappear. In order to teach the monitor the right network and password you may need to move it out of range of the open network (plug it in somewhere else) and set it up.  Then bring it back to the location and it will connect to the network you taught it in setup.
  3. The monitor’s network may turn on and off repeatedly during setup.  Keep trying to connect. Sometimes smartphones are more successful.

My device won’t connect to “AirMonitor_xxxx”

  1. Sometimes smartphones and laptops will not connect to a WiFi network that doesn’t reach the internet.  This is a security feature. You will need to respond to a pop up alert to tell the device to “trust” the network, or “connect anyway.”

I’m connected to the monitor, but I don’t see my network in the list

  1. The monitor can only work with 2.4Ghz networks.  If you are trying to connect to a 5Ghz network, it won’t be able to see it.
  2. The monitor might not be in range.  If the monitor is placed too far from the Wireless Router for the network, it won’t be able to “hear” the network.  Try moving the monitor a bit closer to the router. If your phone has a good WiFi signal, that’s usually a good sign.

My monitor is connected to the network and it still isn’t showing up on the map

  1. The monitor will show up when it’s connected *and registered.  Complete the registration step and check again.

 

Power to the Device

The monitor needs to be connected to a power source in order to collect data.  Here are a few common pitfalls:

  1. The monitor should be plugged in securely, and the USB cable securely connected to the device.  Test the connections.
  2. Be sure that the outlet has power.  If not, check if there is a switch which controls it, or if the outlet has a ground fault circuit interrupter try pushing the “reset” button.
In the event the monitor loses power, once it returns the first thing the monitor will do is look for the WiFi network used in set up.  This helps out a lot if there are outages, or the accidental flip of a switch.

ONLINE REGISTRATION

 

Registration Form Issues

  1. The monitor can be registered and installed in either order.  However, it will not show up on the map until it is registered.  
  2. In general, Clean Air Carolina will handle the device registration for you.  

Map Issues

  1. The monitor’s data is made visible through a Google Maps API. Navigate to and click on your sensor to see it’s data just like you would with regular Google Maps.
  2. If you can’t see your sensor you may need to zoom the map closer in, or adjust the visibility settings in the top left corner.

MONITOR DOWNTIME

Grey Dot on the Map

  1. If the monitor is showing on the map, but is grey, then the monitor has disconnected.  This could mean it doesn’t have power, or is not connected to WiFi. Check “SETUP ISSUES” to see if it’s properly connected.

 

No Point on the Map

  1. It’s possible the monitor has been inactive for too long.  Adjust the monitor visibility settings in the top left of the map to “active all time.”  Then, see “SETUP ISSUES” to reconnect your monitor.
  2. It’s possible the point on the map is in the wrong place.  Contact Clean Air Carolina if you have checked all other options.

MONITOR MAINTENANCE

 

The monitor is pretty self sufficient. But, if it is left without care, the data will not be of high quality.  Regularly check the monitor once a month for damage, debris, and give it a cleaning with a compressed air keyboard cleaner can to spray out the device.  Be sure to get it into the sensors as well.

Suspicious Monitor Data

If you see the monitor data on the map, but it doesn’t match the expectations, either too high or too low, you can check and see if the monitor is working effectively.

  1. If there are large spikes in the data that other sensors in the area don’t also report, it’s possible the sensor is reading localized pollution.  This could be a lawnmower, outdoor grill, or smoke that is entering the sensor exaggerating the readings. If possible, move the sensor away from these nearby sources.  
  2. If the sensor data seems too high consistently, it’s possible the sensor is dirty.  Use a compressed air keyboard cleaner can to spray out the device. Be sure to get it into the sensors.
  3. If the data from the two sensors seems to be inconsistent, showing widely different numbers, there could be a spider or other small creature inside the monitor.  Again, use a compressed air keyboard cleaner can to spray out the device. Be sure to get it into the sensors.

 

RESOURCES

Performance Resources

Here are a few resources to help you better understand the sensor and how to use it.

Return Policy

If you have attempted all of the above steps and are still have trouble with your sensor, contact Clean Air Carolina to see if it’s possible to replace your sensor.

Frequently Asked Questions

Why won’t my PurpleAir™ sensor connect to the WiFi?

There are few reasons why this may occur. Please see steps 1 through 3 of “PurpleAir™ Troubleshooting” for guidance.

If your PurpleAir™ sensor is still not connected, check your WiFi connection on other devices. If this fails, please call Clean Air Carolina at (704) 307-9528.

I’ve just finished setting up my PurpleAir™ sensor. Why won’t it show up on the PurpleAir™ Map?

After registering your PurpleAir™ sensor and connecting it to your WiFi network, it will take some time for the sensor to start to transmit data to the PurpleAir Map™. Once it begins transmitting data to the map, the map marker in your location will light up. This may take up to a day or so.

How can I locate my PurpleAir™ sensor on the map?

To locate a sensor you can search for the location in the search bar shown on the PurpleAir™ Map. To find your sensor, search for the name of your PurpleAir™ sensor, which is the name you gave the sensor when completing the PurpleAir™ registration. See step 4 of “Register your PurpleAir™ sensor”  in this manual for the format you used to name your sensor.

Will the PurpleAir™ sensor give away my location?

If you do not want the exact location of your sensor available online publicly, please move the GPS location of your sensor a couple of blocks away from the structure on which the sensor is installed. When naming your sensor, give it a relative location such as “Ashley Park”, rather than the exact address.

Will my personal information be shared online?

Your personal information, including name and contact information, will not be shared outside of Clean Air Carolina. The only information that will be displayed publicly on the PurpleAir™ map is the location of your sensor (which you can set when you register your device), the name of the sensor (which you can choose when you register your device, and the air quality data that is transmitted via the sensor.

Glossary

Asthma: Chronic lung disease that inflames and narrows the airways. cause wheezing, chest tightness, and shortness of breath.

Chronic Obstructive Pulmonary Disease (COPD): a progressive lung disease that gets worse over time. COPD usually includes chronic bronchitis and emphysema, which make patients hard to breathe.

Crowdsourced: obtained with the help of many people, typically via the internet.

Electron microscope: a microscope with extremely high detection power and magnification much greater than any optical microscope.

Particulate matter (PM), also called particle pollution: any solid or liquid particle suspended in the air.

Real-time: the actual time in which something is taking place.