TL;DR — Low-cost sensors can be used in a wide range of different air quality monitoring projects, either alone or in conjunction with reference-grade air quality monitors, to collect high-quality data about the state of the air. Whether being used to increase public awareness of air quality issues, inform environmental and public policy recommendations, support environmental justice initiatives, create a hybrid network with FRM/FEM technologies, establish non-regulatory supplemental and informational monitoring, or as part of emergency/rapid deployment, the best practices of using low-cost sensors differ from case to case. It is important to keep these practices in mind when determining how to site, deploy, and calibrate sensors, collect air quality data, and communicate the findings to a variety of stakeholders.

The flexibility, affordability, ease-of-use, and scalability of low-cost sensors (LCS) mean they can be employed for a variety of monitoring applications and projects. As LCS technology becomes increasingly prevalent around the world, it is becoming possible to collect air quality data for a wider range of use cases than ever before. In this blog, we’ll discuss some of the most common use cases for low-cost sensors — although new use cases continue to emerge on an ongoing basis!

Some popular use cases for low-cost air monitoring technology include:

  • Increasing public awareness of air quality issues
  • Informing environmental and public policy recommendations
  • Supporting environmental justice work
  • Forming part of hybrid networks, which employ reference-grade monitors and low-cost monitors in conjunction
  • Non-regulatory supplemental and informational monitoring (NSIM)
  • Emergency or rapid air monitoring deployment
  • Implementing air monitoring infrastructure in economically developing areas and/or remote locations
  • Air quality research 

The image below is drawn from a past webinar where we discussed best practices for using low-cost sensors in the urban environment and polled attendees about the major categories of use cases that they are interested in using low-cost sensors for. 

Over 200 of our webinar attendees shared their interest in using low-cost sensors for a variety of different applications as shown above. The more affordable nature, easy deployment, and increased flexibility that comes with low-cost sensors mean that they can be deployed and scaled for many different air monitoring objectives.

For our webinar audience, raising public awareness topped the list — but there was significant interest in all six of the use cases we polled for. You can read here to learn more about the best practices that our webinar panelists shared for employing low-cost sensors in urban environments, or watch the original webinar here.

Seeing air quality sensors proliferate across such a wide range of use cases in recent years, we wanted to take a deeper dive into each of these applications.

Using low-cost sensors to increase public awareness of air quality issues

Low-cost sensors can be used to increase public awareness about the state of local air quality and how individuals and communities can protect themselves from air pollution exposure. 

When using low-cost sensors to expand public awareness, it is important to couple air quality data with greater information or education about what different levels of air quality mean, as well as the significant health and environmental effects that come with poor air quality. Whatever medium is used to communicate the air quality data, there should be clear indications of what the level of air pollution is and what the appropriate behavioral changes are to reduce exposure when needed. A good example of this type of guidance — developed for schools looking to educate children and school staff about air pollution and protect them from its negative effects — is included below here. 

Because this use case focuses on disseminating information about air quality to the public, it is essential that monitoring projects have a plan for how to best communicate this data in a meaningful, actionable way to residents of the community. Air quality indices, such as the U.S.’s Air Quality Index (AQI) can be especially helpful for communicating data and ensuring the public check knows how to protect themselves from air pollution.  Read our blog discussing the most effective ways to communicate air quality data to a variety of audiences here.

One, less conventional way of raising awareness of environmental issues is with art — such as this kinetic sound sculpture project Clarity was involved with. The exhibit, “Moss” by Italian artist Marco Barotti, is driven by air quality data generated by a number of air quality sensors and the World Air Quality Index. The audience is able to experience real-time air quality transformed into a kinetic sound installation — prompting them to consider the dynamic nature of air quality and the impact that air pollution has on health and the environment. 

Informing environmental and public policy recommendations with low-cost sensor data

Low-cost sensors can be used to collect higher-resolution air quality data and create targeted, local air quality policies such as no-burn days, the phasing out of older, high-polluting technologies, and the implementation of low- or zero-emission zones such as London’s Ultra Low Emission Zone

Data quality is especially important when the data are being used to validate or support policy efforts. Air quality data that supports policy recommendations do not need to be ‘regulatory’ grade but needs to at least be acceptable for indicative monitoring purposes and meet the relevant data performance targets. For more information on how to meet USEPA standards using low-cost sensors, read our white paper “Guide to Accurate Particulate Matter Measurements” here.

When conducting research into policy implications, conveying air quality information in standard formats that translates across various audiences is important — for example, using standard measurement units such as micrograms per cubic meter (μg/m3) rather than AQIs which vary from location to location. These measurement units can be paired with information about what different ranges of these values indicate from a public health standpoint to ensure that air quality data is meaningful and actionable to non-technical audiences such as community leaders and regulators as well as researchers.

Supporting environmental justice work

Environmental justice (EJ) programs work to address the disparities between different communities — even those within the same city or region — that exist due to present and/or historical conditions which affect their community health and access to resources. Read our environmental justice-focused blog for more information on the role that  EJ communities play in advancing conversations about air quality.

Low-cost sensors can be used to collect air quality data that ground-truths concerns about air quality issues or suspected high levels of exposure. When looking to use low-cost sensors for EJ purposes, it is important to install them in areas that reflect stakeholders’ actual exposures at the neighborhood level, as the air quality reference monitors deployed at the regional scale can often miss out on local trends and true ground-level exposures — creating a disconnect between published air quality data and the lived experience of EJ communities. 

Data quality is also important when using low-cost sensors for environmental justice work — especially if the data is being used for ground-truthing or to advocate for policy change — to ensure that it is not dismissed as potentially inaccurate. 

Low-cost sensors can be deployed at a variety of sites to support environmental justice work, collecting air quality data that often confirm residents’ long-time suspicions of high air pollution exposure that causes vast negative impacts on the health of their community. Above, a team works to deploy a low-cost sensor in Richmond, where a community-led monitoring project empowers residents with access to high-resolution air quality data.

It is essential that air quality monitoring programs within EJ communities work directly with community leaders and members to have them lead the work in their community, especially since residents can often offer essential local knowledge concerning the highest priority air quality concerns in their communities and even potential fixes. Our community monitoring partners in Richmond, California and San Francisco, California steer the decision-making process for their air monitoring networks, while Clarity provides technical and project support as needed.

For more information on how environmental justice communities can most effectively use air quality monitoring to improve air quality at the neighborhood level, read our interview with our Environmental Project Manager Katie Moore.

Employing low-cost sensors as part of hybrid networks

Low-cost sensors can be deployed as part of hybrid networks along with existing federal reference-grade monitors (FRM/FEMs) to fill in the gaps left behind by these highly-accurate, but expensive and bulky, pieces of equipment.

Because of the lower cost, easier deployment, and flexibility of low-cost sensors, sensors can be deployed at much higher densities than traditional reference-grade monitors, ensuring that air quality trends can be detected block-by-block at the neighborhood level.

Breathe London is one example of a successful hybrid network that employs low-cost sensors to supplement existing reference-grade monitors in the city of London. To date, this program has placed over 350 sensors at schools, hospitals, and other key sites to measure air pollution across the city — after co-locating the sensors alongside reference-grade monitors to achieve higher data accuracy. The use of low-cost sensors helps to increase accessibility to air quality data as well as community engagement with the air monitoring network. You learn more about our partnership with Breathe London to improve London’s air here.

This map of the Breathe London air sensor network map demonstrates how a dense network of hundreds of air sensors can catch localized air quality trends and air pollution hotspots often missed by the reference monitoring network — especially in the urban context, where air quality can differ significantly from block to block. 

When using sensors for official purposes like a hybrid network providing government-sanctioned data to the public, it is important to ensure that the data sourced from both reference-grade monitors and low-cost sensors are as accurate as possible. Rigorous calibration and quality assurance/quality control processes can assure that low-cost sensor data is high quality — to learn more, read our blog detailing the LCS calibration process.

Non-regulatory supplemental and informational monitoring 

Non-regulatory supplemental and informational monitoring (NSIM) refers to deploying low-cost sensors and other air monitoring equipment that is not approved for regulatory use to collect a greater volume of air quality data. These data are used for informational purposes rather than regulatory ones, painting a more detailed picture of the air quality in a given region.

One air quality monitoring agency, the Monterey Bay Air Resources District (MBARD), manages air quality in the North Central Coast Air Basin in California. In response to increased citizen concern about the health impacts of air pollution from wildfire smoke, MBARD deployed low-cost sensors across multiple municipalities to provide over 750,000 residents with access to real-time air quality data. 

Though these sensors do not provide regulatory data like the agency’s reference-grade monitors, they provide a wealth of information to those concerned about the region’s air quality, especially given the harsh wildfire seasons they have seen in recent years. To learn more about MBARD’s use of low-cost sensors for non-regulatory supplemental and informational monitoring, see our customer story here.

Open access air quality data can play a highly important role in NSIM because of the wealth of air quality information it provides to a variety of stakeholders, from residents to lawmakers to researchers. To learn more about the ways that open access to air quality data supports air quality awareness and a variety of initiatives to improve the air, read our blog here.

Low-cost sensors for emergency and rapid deployment

Low-cost sensors’ flexibility means that they can be quickly deployed in a variety of emergency contexts to measure air quality, such as during wildfire events or industrial accidents.

Ensuring that the monitoring network uses durable, easily-deployed air quality monitoring equipment means that the air quality sensors can be utilized for emergency needs, when and where they are needed. Because of the rapidly changing conditions that may occur in an emergency context, it is advisable to use low-cost sensors with cellular and/or WiFi connectivity to ensure that the data collected can be accessed without the need for internet connectivity.

Brightline Defense, an environmental justice non-profit based in San Francisco, deployed low-cost sensors during the record-breaking 2020 wildfire season in California to measure air quality and protect public health. Read our customer story with Brightline Defense here to learn more.

The image above shows a low-cost sensor deployed as part of Brightline Defense’s monitoring network in San Francisco, California during the devastating wildfire season that occurred in 2020. During times of severe air pollution, low-cost sensors can be rapidly deployed to collect air quality data that helps inform decision-making to protect public and environmental health.

Deploying low-cost sensors in economically developing areas and/or remote locations

Low-cost sensors can be help implement air quality monitoring in economically developing areas and/or remote locations where using reference-grade monitors is not economically or technically feasible. 

A solar-powered air sensor deployed in Saudi Arabia measures air pollution without the need for electrical infrastructure or WiFi connectivity. 

Because low-cost sensors are much less expensive and require less infrastructure than reference monitors, the barriers to entry are much lower. See our blog about how using low-cost sensors in economically developing countries can be a useful tool for improving air quality here for more information.

Some best practices for low-cost sensor use in economically developing countries involve:

  • Providing clear, informed data on the different low-cost sensor technologies available and the specificities of their use so that the most appropriate technology can be utilized for the monitoring project. One such source, the USEPA’s Air Sensor Toolbox, provides information on the technologies available in the U.S.
  • Develop a plan to site, deploy, and calibrate the low-cost sensors to ensure a successful network that meets the project’s specific needs; for example, this may involve considering what spatial density of sensors would be best
  • Using low-cost sensors that can operate during times of intermittent power and data connectivity
  • Develop best practices in data management, including how the data is processed and the quality assurance/quality control practices that are used to ensure high-quality, accurate data
  • Ensure that the air quality data is accessible and comprehensible to the public so that everyone affected by poor air quality, from citizens to lawmakers, can benefit from information about the state of their air and how to protect themselves from exposure

Air quality research

Air quality research is key to advancing our collective understanding of air pollution, and Clarity is proud to support air quality research with discounted offerings for academic researchers. 

Air quality researchers can utilize flexible, affordable air quality measurement technology such as LCS to collect the air quality measurements they need to support their research. To learn more about the use of LCS in different research applications, check out our customer story with Institute for Atmospheric and Earth System Research here.  

Because air quality can focus on a variety of different parameters, such as different air pollutants, it is important that the technology used to collect data can be functional for these different needs. 

It is also crucial that researchers understand the typical performance of the devices that they intend to use to have context for the data they collect. Remote calibration and device management can also be useful for minimizing the overhead associated with managing an air quality research program — particularly for research conducted in remote or less accessible locations. 

Here are a few of the academic research papers that Clarity has supported: 

Air quality data is only as valuable as we make it — consider how and why you will use air sensor data

LCS can be effectively used across a wide variety of air quality monitoring use cases — although equipment needs, network design, and best practices for data collection, processing, and communication vary significantly across these use cases. This is why it's key to have clear end-goals for your monitoring work in mind before investing in a low-cost air sensor network, to ensure that you invest in the proper resources — aside from the monitoring equipment itself — required to get the value you are looking for out of the technology. 

Interested in setting up a low-cost air sensor network for any of these — or another — use case? Get in touch with our team to learn more about how our Sensing-as-a-Service air monitoring solution makes air quality measurement easier and more cost-effective for governments, businesses, and community organizations!