Using Air Quality Sensors for Smoke: What to Consider
Air sensors—also called portable, low- or lower-cost air quality sensors or sometimes “monitors”—have made it easier for people to monitor the air quality where they spend time. Because they provide localized readings, air sensors can help you make decisions about personal activities, but they are not intended to replace the highly accurate readings taken by regulatory monitors typically used by state, local, and Tribal air agencies.
Learning how to use an air sensor can help you get the most useful information from your device during a wildfire smoke event. This fact sheet focuses on using sensors to measure fine particulate matter (PM2.5), one of the main pollutants in wildfire smoke. Some air sensors measure other pollutants like PM10 or PM1, nitrogen oxides, carbon dioxide, and ozone. The recommendations in this fact sheet may not apply to these sensors because they may perform differently than PM2.5 sensors.
On this page:
- How Air Sensors Can Help You
- How to Choose an Air Sensor
- Where to Place an Air Sensor
- Consider Air Sensor Performance
- Resources
How Air Sensors Can Help You
During wildfire smoke events, air sensors can provide useful, real-time information about PM2.5 levels outdoors and indoors. Data from sensors can help you:
- Make decisions about where to go to avoid smoke exposure.
- Identify better times to go outside (ideally when smoke levels are relatively low).
- Understand what actions, like air filtration, most effectively reduce your smoke exposure indoors.
How to Choose an Air Sensor
Look for a sensor that measures PM2.5. Here are some things to consider before purchasing a sensor to measure smoke:
How will you access the data from your sensor?
Some sensors:
- Connect to the internet via Wi-Fi or cellular networks and allow you to view or download data from a website or app.
- Store data on a removable memory card that you can analyze on a computer.
- Display graphics, colors, or numbers directly on the device.
What type of sensor best fits your needs?
For example:
- A sensor with a display provides information about current PM2.5 levels quickly.
- One that connects to a website or app will allow you to view your PM2.5 levels remotely or compare it to other areas.
How will you power the sensor?
Some sensors:
- Plug into a wall outlet.
- Use small solar panel/battery systems.
- Run off a battery.
Where to Place an Air Sensor
Before you place an air sensor, consider your objectives: What do I want to learn about PM2.5 from this sensor? For example:
- Using sensors outdoors can help you decide whether to hold outdoor sports practice or engage in other outdoor activities.
- Using a sensor in the room where you will use an air cleaner can help you decide when to turn on your air cleaner.
These objectives will help you understand where to place the sensor and which areas to avoid.
- Try to place the sensor 3–6 feet off the ground (at breathing height) and in a location that does not restrict airflow to the sensor.
- Avoid placing indoor sensors near exterior doors, windows, stoves, heating and cooling vents, humidifiers, or showers where changes in temperature and humidity can negatively impact sensor readings.
In addition, consider logistics as you select your location, including:
- Providing power for the sensor.
- Accessing the sensor data.
- Connecting the sensor to an existing communications network.
- Placing the sensor where it will not be unplugged or damaged.
- Getting permission to monitor at the site, if not on your property.
See the Resources section for links to more detailed information about siting sensors.
Consider Air Sensor Performance
Some monitoring applications may require higher quality data and more accurate sensors. For information on sensor accuracy and related topics, see:
- The Enhanced Air Sensor Guidebook (EPA)
- Performance of low-cost indoor air pollution monitors (EPA)
- Air Quality Sensor Performance Evaluation Center (AQ-SPEC) (South Coast Air Quality Management District)
See the Understanding Sensor Data Wildfire Guide fact sheet to learn more.
EPA developed and tested air sensor performance standards, though none explicitly account for performance in smoke. EPA researchers made several recommendations for how the protocols could be adapted to better understand performance in smoke.
Resources
Information on Air Quality
Check out the AirNow Fire and Smoke Map, your state air quality website, or your local news for air quality information. Access these resources using the links below.
- AirNow Fire and Smoke Map
- Wildfire Guide Fact Sheets
- Resources and Information on Wildland Fires and Smoke
- Infographics on Staying Safe Before, During and After Fires
