First, ask yourself what you plan to do with the data. Are you simply interested in whether a particular pollutant is present in the air? Or do you want to know more details – such as how much of the pollutant is in the air? That will help determine what type of equipment you need – and how much it will cost.

Visit EPA’s Air Sensor Toolbox to learn more about the potential use of air quality monitoring sensors. This site includes resources that provide information on what to consider when selecting an air sensor for use, including the Air Sensor Guidebook and the multiple sensor evaluation reports.

Potential uses for new air sensor technologies include:

1) measuring local air quality to better understand sources of pollution, 2) science education, 3) locating costly leaks at industrial facilities, 4) participating in citizen science, 5) conducting research, and 6) supplementing regulatory air quality measurements.

Air sensors are being developed to measure a variety of common air pollutants such as ozone, particulate matter, and a number of hazardous air pollutants, also known as air toxics.

EPA’s laboratory and field-based evaluations have indicated a wide range in performance for lower-cost sensors of similar value (< $2,500). In general, when calibrated sensors measure air pollutant gases (such as ozone and nitrogen dioxide), they are often capable of estimating pollutant values within 30 percent of the true or actual value, compared to the regulatory-grade monitors used to implement the National Ambient Air Quality Standards for these pollutants. Tests by EPA researchers reveal that only a few sensors are capable of providing particulate matter (PM) estimates within 30 percent agreement of the regulatory-grade monitors. Environmental conditions such as relative humidity and possibly even the type of pollutant being monitored appear to influence whether readings from low-cost sensors compare with those provided by the regulatory-grade monitors..

• Low and high temperatures, as well as humidity over 95 percent, may cause inaccurate readings.
• Most sensors need a physical enclosure in order to protect them from weather conditions.
• Most sensors are only usable for one to two years, after which readings will likely become inaccurate.
• For sensors that do not collect GPS location, using cellphones or GPS trackers can be an affordable way to collect information on how different locations have different amounts or types of pollution. GPS information can also help with mobile air monitoring.
• Many sensors do not display data on a screen in real-time. The user must download the data and view it on a computer.
• Sensors do not collect data 100 percent of the time. Technology can malfunction, power supplies can go out, and weather can interfere with readings. Because of this, it is important to check sensors in the field at least once a week to make sure they are running correctly.

EPA actively supports the development, evaluation and piloting of new air monitoring technologies for use by states, communities, tribes, citizen scientists and industry. The goal is to advance air quality monitoring capabilities with instruments and approaches that will enhance current monitoring activities, provide new data not available today, improve access with lower-cost, real-time technology and provide more cost-effective monitoring to help better characterize air quality. EPA is spearheading many efforts in the U.S. to advance the next generation air monitoring technology. They include:

• Conducting field and laboratory studies to evaluate new sensors, and develop novel ones
• Demonstrating real-time air monitoring stations with the Village Green Project in communities
• Providing resources and training on air sensors for citizens through the online Air Sensor Toolbox.
• Collaborating with communities on air sensor projects.
• Providing assistance to communities impacted by many sources of air pollutants with air monitoring projects
• Providing information on sensor technology funding opportunities for small businesses
• Partnering with sensor developers to advance the technology .

EPA recognizes that recent advances in low-cost sensor technologies for air quality measurement are inspiring environmental scientists and the general public to seek information about them for their own use. The technology is providing more cost-effective ways to monitor air quality. It is also helping communities learn more about local air quality. EPA’s support of the development of next generation air monitoring tools and approaches increases awareness by citizens and communities about air quality and provides new ways to address air quality concerns.

EPA’s role is to encourage and assess the development of air sensors in the marketplace so that they are more accessible, less costly and provide accurate results. Commercial air sensors are becoming readily available. EPA does not have a loan program, does not sell these devices, and does not endorse any particular product.

While EPA is dedicated to the advancement of next generation air monitoring technology and is supporting development and use of next generation air monitoring technology, air sensor devices are not available for loan to citizens for their personal use.

Agency scientists are involved in the evaluation of some air sensor monitors for use by citizens and provide the information in reports, but do not make any endorsements or recommendations for their use. EPA has a formal process for the evaluation of technologies proposed for use as Federal Equivalency or Federal Reference monitors that are used for monitoring compliance with the National Ambient Air Quality Standards. These are considered the gold standard for air quality monitoring.

As a federal agency, EPA cannot make recommendations to the public on the use of particular commercial air sensor monitors for citizen science projects, nor can the agency endorse commercial products. EPA provides resources for conducting air monitoring projects on the Air Sensor Toolbox, including performance evaluation reports by EPA scientists of select air sensors.