Citizen Science/Air Quality Sensors

Learn how technological advances to better understand air quality have become more assessability for the general public and what that means for air quality awareness.

Aq Sensors

The air sensor technology market is expanding as more companies make lower-cost portable monitors available to the public. The new low-cost, highly portable air quality sensors give people the opportunity to use this technology for a wide range of applications like research, personal exposure monitoring, supplementing existing monitoring, investigating emission sources, education, and awareness. Learn more about air quality sensor and how they could impact your life.

What are Air Quality Sensors

Air Quality Sensors are devices that detect and measure specific chemical/pollutants in the air, these devices can have many use cases like monitoring indoor air quality, outdoor air quality or portable sensors that can be moved around frequently.

Air pollution sensors are still in an early stage of technology development, and many sensors have not yet been evaluated to determine the accuracy of their measurements. Sensor performance requirements differ according to the application. The quality of a measurement is dictated by the basic performance of the sensor, the way the sensor is operated, and the way its measurements are analyzed. Understanding the strengths and limitations of an air sensor is important in making sure the data collected is useful for the intended purpose.

What to look for in a Sensor

There are so many different types of sensors entering the market so it is important to do your research and know before you buy.

  1. Select your target pollutant - different sensors can measure different pollutants.
  2. Consider detection range and detection limit - depending on how close you are to a pollution source, the ability of a sensor to be accurate at either very low or very high concentrations must be understood before you collect any measurements.
  3. Consider precision and bias - buyers should consult the manufacturer's specification about the reported precision and bias of the sensor to better understand what their measurements mean compared to other instruments.
  4. Identify calibration requirement - calibration is the process of checking and adjusting an
    instrument’s measurements to ensure that it is reporting accurate data - this is important because
    sensor performance can change over time.
  5. Understand response time - a sensor may be quick or slow to measure a pollutant in the air.
    A sensor that responds quickly may be useful for mobile monitoring and for observing very rapid changes in pollutant concentrations. A sensor that responds slowly may be more suited to stationary monitoring of pollutants that vary in concentration gradually.
  6. Verify durability and quality of construction - durability is referring to a sensor’s ability to
    endure wear and tear and continue to perform.
  7. Packaging - packaging refers to the material used to contain the sensor system components.
    Packaging can be used to provide protection from water, light, temperature variations (by adding heaters or cooling fans), and electromagnetic noise.
  8. Usability - usability refers to the ease of use of a sensor; is it straightforward
    to operate? Air sensors are used by a wide variety of people, ranging from those with no formal training in air quality science to researchers who have many years of advanced training and expertise.
  9. Cost - The cost of sensor technology may vary greatly depending on the pollutant to be
    measured and the degree of accuracy and sensitivity one needs. In general terms, costs often range from $100 to $2500 for what might be considered “consumer-based” air quality sensors. Even within a given pollutant, the cost range might be very large depending on the features of the device.

To help the public better understand the sensors on the market the EPA has a sensor performance evaluation tool.

What Does My Sensor Readings Mean for Me

EPA is launching a pilot project to test a new tool for making instantaneous outdoor air quality data useful for the public. The new “sensor scale” is designed to be used with air quality sensors that provide data in short time increments–often as little as one minute. EPA developed the scale to help people understand the one-minute data the stations provide and how to use those data as an additional tool for planning outdoor activities. The following tables provide some context to outdoor Ozone and PM2.5 sensors.

Epa Sensor Scale

What Can I Do with my Air Quality Sensor Data

If you have sensor data that you would like to share or if you would like to view other sensor data the EPA developed the Real Time Geospatial Data Viewer (RETIGO). RETIGO is a free, web-based tool that can be used to explore environmental data that you have collected either stationary or in motion (e.g., air quality sensors added to a bike).

  • RETIGO allows you to add data from nearby air quality and meteorological stations.
  • RETIGO can be used by anyone to explore data that they collected, but it does not move the data from the user’s computer, unless you decide to post your data to the RETIGO data repository.
  • To collect the data, monitoring equipment is needed and ranges in price from ten dollar sensors, on up to professional grade equipment costing tens of thousands of dollars.

EPA's Air Monitoring, Measuring, and Emissions Research site has an array of information on emerging technologies for air monitoring. RETIGO reads plain text data files, which can be either space or comma delimited.