Air sensors are instruments that measure air quality conditions in near real time. Sensors are not regulatory monitors because they cannot meet the rigorous EPA requirements (refer to table below), meaning they are not used to enforce laws. More information regarding regulatory monitors is in MPCA's air monitoring fact sheet.
These instruments can be effective tools for understanding ambient air quality:
- help us learn about hyper-local air quality issues; this can be beneficial in community air monitoring efforts and supporting air pollution reduction
- educate local residents on their own air quality, especially in environmental justice areas, where communities have historically borne disproportionate pollution burden
- help us fill gaps in the regulatory monitoring network, see trends, and screen for hot spots; this can be beneficial in informing where to install regulatory monitors
- be quickly deployed
- typically use Wi-Fi and a power source; some sensors use solar panels or have cellular capabilities
- collect a lot of data – often every minute
Minnesota air sensor data
AirSeRV database
Use the interactive map to search and view data from sensors sampling for air pollutants. Results are presented “as is” and may have different levels of accuracy depending on the sensor.
This database/map includes all of the sensors the agency operates and has deployed across the state, in addition to sensors from projects we're partnering or assisting with. Contact us to talk about getting your sensor on the map: air.sensors.mpca@state.mn.us
Sensor types
A variety of air sensors may be used to measure different pollutants. Sensors can measure particulate matter, gases like ozone, or even volatile organic compounds (VOCs). Some sensors measure total VOCs while others take a sample of air to test in a lab to determine which VOCs are present. Methods of measurement, analysis and data quality can vary across sensor types.
MPCA does not have the resources to evaluate all sensor types, but an agency in California has evaluated performance and reliability of many sensor types. These reports and resources are available on the web site of the Air Quality Sensor Performance Evaluation Center.
| Sensors | Regulatory monitors | |
|---|---|---|
| Cost | range from $300 to $15,000 | $60,000 to purchase and set up; plus $5,000 for annual maintenance and external labor costs |
| Lifespan | one to three years, depending on the pollutant it detects; also possibility of less accuracy over time | 10 years, if not longer; they are calibrated and maintained to ensure accuracy |
| Locations | can be located almost anywhere using Wi-Fi or cellular data and batteries | must be located where there is access to electricity and internet, and where people and animals can't tamper with them. The U.S. Environmental Protection Agency (EPA) must approve where we can locate regulatory monitors |
| Set up | can be installed quickly | cannot be set up quickly due to strict siting requirements; only EPA-approved monitors can be used |
| Sample collection and testing | Sample collection and pollution volume can be done by the sensor itself. Some sensors can collect samples to be analyzed using EPA-approved methods (at extra cost) to validate their collection. | Sample collection can only be done by a trained operator. Samples are transported, stored, and analyzed using EPA-mandated methods by a trained chemist. |
| Maintenance | Some sensors allow easy user operation for maintenance and are sometimes self-maintaining. Some sensors are disposable or costly to maintain. | Each monitor requires annual maintenance which can be costly. Equipment must be calibrated daily, monthly, or annually. |
| Calibration | Sensors can come pre-calibrated or offer different calibrations. Some can be re-calibrated by the user or by the company. | Regulatory monitors must be calibrated every two to three months by a trained staff. |
| Data quality | Quality assurance (QA) can be performed with sensors; it doesn't have to be in-depth or technical. | Laboratory data are required to be quality assured and validated by trained staff, using EPA requirements. |
| Use of data for Enforcement | Sensor data cannot be used in enforcement actions, but they can aid in determining where to place regulatory monitors. | Monitoring data that is analyzed in an approved lab and is properly checked for quality can be used in enforcement actions. |
Community air sensor projects
Air sensor projects can aid communities in better understanding the air they are breathing. This is especially important in environmental justice areas, where some communities are more vulnerable to health complications from poor air quality. Using air sensors can give communities the ability to evaluate their exposure to air pollutants and use tangible data when advocating for themselves.
Using funding from the 2023 Legislature, three sensor projects are underway:
- The OSLUV Project will collaborate with the Frogtown and Hamline Midway communities to gather air quality data under the project name Neighbors for Clean Air. Located near major roadways, these communities have experienced some of the highest rates of asthma-related emergency department visits and hospitalizations across all age groups in comparison to state and metro averages.
- The University of Minnesota Urban Research and Outreach-Engagement Center is deploying 23 QuantAQ Modulair air sensors for fine-particle and gaseous pollutants along the West Broadway corridor of North Minneapolis. The project will include a stationary node network sensor, mobile lab pollutant mapping, and indoor air mitigation efforts. Its two main foci are data collection and analysis, along with initiatives to promote community engagement in air quality education and associated health risks prevention.
- The Great Plains Institute, partnering with TD Enviro and JustAir, will implement AIRNET, an air quality monitoring plan across six metro area communities (East Phillips Neighborhood Institute, North End Neighborhood Organization, Payne-Phalen Community Council, Greater East Side Community Council, West 7th/Fort Road Federation, Union Park District Council) for two years. AIRNET will provide live monitoring data following strict QA practices and incorporate community input and needs in the design phase.
Older examples of sensors being used in community projects in Minnesota: