What to keep in mind when planning and deploying air quality sensors in your community

More and more communities around the world are starting their own air quality monitoring projects, or have already deployed air quality monitoring devices and are actively using the data. We regularly receive requests to discuss potential projects, and with this article we want to share some of our know-how with you. This article will give you hints and pointers what to think about when developing the concept for your own air quality monitoring project, and you can use the information below to start fleshing out a concept draft.

Defining your project goal

Generally, first you should think about why you want to collect air quality data, as this will influence all your further decision making. Start answering the following questions in your conceptual development:

Why do you want to collect air quality data?
Who is the intended recipient of the collected data? How are they supposed to use the data?
(How) do you want to involve the local community in the project?

From the project goal, you will then be able to derive requirements regarding the monitoring locations, sensor requirements and software needs. Ideally you will be able to answer the following question with confidence: If you look back on your air quality project in five years – what would have needed to happen for your project to be seen as successful?

Selecting the right locations for your air quality sensors

Based on the answers of the previous questions, you can then start designing a monitoring network:

Which air quality parameters are relevant for your stakeholders? Do you want to collect any other parameters, like temperature or noise levels?
Which sites do you have available to install air quality sensors on? Think street lights, traffic lights, bus stops, public buildings and other public infrastructure.
What infrastructure do you have in place to support the sensors? Do you have power available? What connectivity options may be the best for you?
How far do you want to comply to national regulation or international recommendations on air quality monitoring locations?

Depending on your project goal, the locations where you will want to install sensors can vary widely. For instance: If you intend to use the data in traffic management you will likely want to install air quality sensors close to busy streets and intersections, while a community resilience project in which you want to protect and inform community members will require you to install sensors in residential areas and around schools and kindergartens. In some cases, it can also make sense to work with community members to place sensors directly with them.

Locations should be accessible to facilitate both maintenance on the sensors, as well as potential replacements in case of defects or upgrades.

There might also be requirements born from national regulation on air quality monitoring (that typically only apply to the national-level air quality monitoring network), for example regarding the installation height of sensors. Some of these requirements always make sense to ensure good data quality, while others might not need to apply to your project. You should define for yourself how important these requirements are for you, and to what extend you want to comply to these regulations.

Selecting the right sensors for your air quality monitoring project

After collecting information about likely air quality monitoring locations, you should then think about your requirements regarding the air quality sensors:

Which air quality parameters should they be able to measure? Do you want to capture data on any other environmental parameters, such as climate or noise levels?
What pollution concentrations do you expect in your community?
What are your requirements regarding connectivity?
Will you be able to supply power, or will the sensors need to operate autonomously via solar power?
How accurate should the sensors be?
What kind of calibration should the sensors come with?

While national-level air quality monitoring campaigns typically rely on traditional automated air quality monitoring stations, such devices can easily costs hundreds of thousands of dollars and require a lot of space and maintenance. Their use typically does not make sense on a community level. At the other end of the spectrum, there are very low cost sensors available between 10 to a few hundreds of dollars. The main issue here is that these sensors often do not have specific sensing elements for individual air quality parameters (and produce a rather ambiguous “air quality level” reading without any scientific foundation), use very cheap components and/or are not calibrated. While they can be a good tool for individuals to start exploring the topic of air quality, community administrations should aim at more trustworthy devices.

Here, lower- and mid-cost sensors are better suited to collect environmental data. Their total cost of ownership starts at between 1,500 to 4,000 USD, depending on their configuration and the length of the planned monitoring campaign. If the project is planned for multiple years from the get-go, this can significantly lower the annual cost of the solution.

Some of these questions you can be directly answered based off your answers above; for example whether or not you will be able to supply power to the sensors decides whether they will need to work with power from solar panels. The question about calibration and accuracy has the highest impact on your total project cost, as highly accurate measurement devices tend to cost significantly more than sensors used for indicative monitoring campaigns. You should also be aware how often the sensors you select require calibration and/or maintenance, and what their usual lifetime looks like. Some vendors, like Breeze Technologies, also offer subscription models through which ongoing calibration, data quality checks and sensor replacement are covered, so that you do not need to worry about this topic.

Selecting the right partner for your air quality monitoring project

It is usually more efficient to work with a supplier that can provide a holistic solution for air quality management – from monitoring over analytics and public data sharing software up to custom project advisory and data analyses. Think about which capabilities your partner should have. In principle your partner should always:

Be able to certify that the sensors have been properly installed
Regularly check the data quality from your sensors
Regularly calibrate the deployed sensors
Replace defective sensors or change sensing elements of sensors with deteriorated data quality

Additionally you may want to think about:

Whether or not your partner should support you with project concept development and sensor placement (see above)
Whether your partner should install the sensors or you have resources to do so
From where you may want to procure software for data analysis and data sharing with your community – many providers of air quality sensors provide these solutions as well

Air quality sensors, particularly gas sensors for parameters like NO_x or ozone, require ongoing calibration. You should definitely discuss with your partner how often their sensors require calibration and how often they need to be maintained or replaced. A good partner will also support you in ensuring continously high data quality in your measurements. Additionally, you may want to discuss data rights with your partner of choice. While at Breeze Technologies, our customers are always the owners of their sensors’ data, some vendors handle this topic differently.

Selecting the right software

Depending on who is the intended audience of the collected air quality data and how they are supposed to use it, you will need different software to visualize it or enable its analysis. In some cases your community may already have a community dashboard into which the data should also be integrated.

You should think about whether a simple visualization on a dashboard is sufficient for your use case, or whether you need specialized software for more in-depth data analysis or better public engagement; a dedicated air quality portal for community members may, for example, also provide context around the different air quality parameters, air pollution limits, or provide relevant behavioural advice. However, integration into your horizontal smart city platforms should still be possible, as you may want to identify correlations between air quality data and other datasets you are collecting.

Potential functionality for expert users in your community administration could be:

Administering metadata about the sensors’ locations
Integrating information about your air quality sensors’ health and maintenance cycle
Providing aggregated data views that support identifying trends and patterns
Offering comparison to national pollution thresholds or international air quality recommendations
Correlating air quality data with other environmental datasets such as meteorological data to identify sources or causes of pollution
Provide advice and action recommendations around improving air quality through policy, community planning and management
Integrating existing air quality datasets, e.g. from satellites or national agencies
Offering real-time alerts based on the collected datasets

For your community members, other functionality might be more relevant:

Providing rated air quality data based on national or international air quality indexes
Giving advice on what actions to take based on the shared air quality data, e.g. when to avoid outdoor activities
Providing forecasts or reports for their neighborhood’s air quality

Once you have fleshed out the software requirements for your project, you can screen the market for available tools like our Environmental Intelligence Cloud.

Final words

Each community is different, and therefore a different solution may fit the current needs. Those needs may also change over time. It is therefore important to stay flexible in potentially deploying additional sensors, software and solutions, or replacing previously implemented ones. Data ownership and open interfaces (APIs) should therefore be important considerations.

Additionally, we have made the experience that in most air quality projects goals change over time. Where just creating an overview over your community’s air quality may have been the original goal, measurably improving air quality may be the project’s next step once you have identified locations with lower air quality in your community. Keep this in mind when selecting one or multiple providers of air quality sensors and software and have a look at their capabilities beyond your current need.

Are you unsure about certain planning steps or are you missing some information in your organization? Breeze Technologies can support you throughout the planning and implementation of your project. Our team of environmental scientists has more than a decade of experience in planning and executing on air quality monitoring and management projects with small and large communities around the globe, and we will be happy to assist you as well. Simply reach out to us through out contact form – we are happy to talk!