Clarity Node-S Siting Guide

How to select appropriate locations for deploying a Clarity Node-S.

Finding the right site for your devices is often a balance of scientific or technical considerations with the practical on the ground realities.
There is no one checklist that will work perfectly for every deployment, but we've outlined some key guidelines in this article.
If you have questions about identifying the best sites for your project, please reach out to us at support@clarity.io and we’re happy to help.

Step 1: Determine Your Project Goal(s)

The best locations for your devices will be guided by your projects goals, so it is important to clarify these before beginning the siting process.

Do you want to measure the impacts of a specific source?
Are you concerned with air quality at specific sites like schools?
Do you want to assess the air quality more generally within a community?

Below is a table with some example project goals and how they would impact siting decisions:

Project Goal	Siting Strategy
Assess air quality impacts of a particular source	Place devices both up- and down-wind of the source location Place devices in locations where exposure population is
Understand pollution exposure for sensitive communities like children and the elderly	Place devices at day care centers, schools, or nursing homes
Assess a policy intervention	Place devices in areas impacted by the policy change as well as areas without the intervention Monitor before and after intervention implemented
Have a general understanding of air quality within a community	Place devices dispersed throughout the area of interest Capture a wide variety of types of sites
Learn about air quality in countries without an existing regulatory monitoring network	Deploy devices following similar guidelines as reference monitoring networks

Once you have determined your project goals, you can begin to identify potential sites that could host your devices. In general, it is good to identify more sites than you will eventually need as practical requirements will eliminate sites from consideration (e.g., security, site permissions, power access, etc.).

Step 2: Securing Site Permissions

If your potential sites are owned or operated by someone not involved in the project, it is important to reach out early to begin the process of securing any permissions needed to site a node. Some may require formal agreements.

The following information will be useful to discuss with site owner:

Site Access: While maintenance is minimal, how you or someone the project team will gain access to the site in case maintenance of the device is needed.
Installation: How devices will be secured to the site
Power requirements: While the Clarity Node-S operates independently using its solar panel and battery and therefore requires no additional power access from the site owner, it can also be powered externally if necessary. Note: If powered externally, the power cord connection to the power source will need to be waterproofed.

Step 3: Site Survey

It is important to survey the site prior to the deployment date, if possible. A site survey will help with the following:

Identify exactly where you will mount the device
Make sure that you have all the necessary tools and mounting accessories to install. You can find more information about the mounting options and supplies needed on the page deploying your Node-S.
It is often helpful to take photos of the site or draw diagrams that you can refer to later.

Once at the site you will need to identify a mounting location. The node can be secured to a pole, fence or railing using zip ties or hose clamps. The Node-S can also be wall mounted.

Note: currently it is not possible to wall mount a device with a solar shield

An appropriate mounting location will need to:

Be at least 6 meters (20 ft) away from any obvious pollution sources like an exhaust vent, generator, or outdoor grill,
Allow the air inlet/outlet to be facing down & unobstructed to allow for adequate air flow. Ideally you would have >270° of free airflow around the inlet. There should be no less than 180° free air flow,
Ideally, the monitors would be placed away from buildings to allow for greater airflow. If you need to install the monitor on a building surface, place it on the upwind side of the building,
Allow for mounting at a height of approximately 3-5 m (10-16 ft) from street level to measure general population exposure; higher to capture data on more regional air quality,
Be in a secure location, if possible behind a fence or in areas that aren’t highly trafficked,
Allow for enough sunlight to charge the device, if using the solar panel. It’s important to check that the location is not in the shadow of buildings, trees or other infrastructure. The device and solar panel will need to be facing south (northern hemisphere) or north (southern hemisphere)*

Note: For the Node-S to operate on its default sampling frequency, it needs an average of 1 hour of sun each day. This does not have to be spread evenly (i.e. you could have four hours of sun on one day, rather than one hour over four days). A fully charged node will be able to operate for approximately 17 days without any sun exposure.

Other Resources

Below are listed some additional resources about siting air monitors that may be useful as you go through the siting process:

California Air Resources Board (CARB) Siting Criteria

US EPA Air Sensor Guidebook

Guide for Monitoring Air Quality in London

European Union (EU) Air Quality Directives

Guidebook for Developing a Community Monitoring Network: Steps, Lessons, and Recommendations from the Imperial County Community Air Monitoring Project