Black Carbon Module Siting Guide

How to select appropriate locations for deploying a Clarity Black Carbon Module.

As with any air quality instrument, proper location is necessary to provide actionable insight. With the Clarity Black Carbon module, choice of monitoring site will depend on project-specific goals as well as knowledge of black carbon emission sources. This guide offers a few things to consider when choosing a monitoring site for your project. 

Common black carbon emission sources

Black carbon (BC) is emitted through different types of combustion, including biomass burning (such as wood heating, cook stoves, and forest fires) and fossil fuel combustion (such as vehicle emissions and coal-fired power plants). Unlike other air pollutants (such as ozone and some components of PM_2.5), black carbon is only formed as a particle directly from the emission source, and there is no chemical formation away from the source. This makes the Clarity Black Carbon Module an excellent instrument to highlight combustion emission hotspots. 

Monitoring site categories and typical concentrations

It is sometimes useful to consider potential sites as broad categories. Common monitoring site categories include near-road, urban background, rural/regional background, and smoke-impacted sites. 

Project-specific considerations

Keeping project goals in mind is key when choosing a monitoring location. While specific goals may vary widely across projects, here are a few examples to start the discussion:

• Highlight a potential major emission source: Locating the instrument near a potential source of interest (such as a power plant or industrial facility) allows investigation into potential major combustion emitters. If possible, choosing a second site further away (or upwind) from the source allows for a comparison to background-level concentrations.

• Explore air quality trends related to traffic emissions: Choosing sites near roads (within tens of meters) and busy intersections will allow for direct comparison of trends in traffic emissions. It may also be useful to choose an additional site away from a major road as a comparison (e.g., an urban or regional background site). 

• Quantify BC concentrations in an urban area: Selecting sites within the urban area but not in close proximity of major sources allows for quantification of typical black carbon concentrations in the area. Though, note that BC concentrations may vary considerably across a single city due to emission source density. Placing several monitors in different neighborhoods allows for a comparison of potential hot spots throughout the city. 

• Compare impacts of urban emissions with wildfire emissions: The Clarity Black Carbon Module offers estimates of the percent of observed BC concentrations attributed to fossil fuel combustion (such as urban traffic emissions) or biomass burning (such as from wildfires). Locating the instrument in urban or rural areas at risk of wildfire smoke episodes allows for source apportionment of the particulate matter plume. 

General air quality monitor siting best practices

Finally, it is important to keep in mind best practices for where to place your Clarity Black Carbon Module once you have found a location of interest. The Clarity Black Carbon Module should:

• Be at least 6 meters away from any obvious pollution sources like an exhaust vent, generator, or outdoor grill
• Be approximately 2-5 meters above the ground (or higher to capture more regional exposure concentrations
• Position away from physical obstructions such as buildings (at least 2 meters away) or trees (at least 10 meters from the drip line). If you need to install the monitor on a building surface, place it on the upwind side of the building
• Have an unrestricted airflow 180-270 degrees around the module's air inlet
• Be installed at a location or a height to reduce risks of vandalism, tampering, and theft
• Keep in mind solar panel efficacy consideration if you are using the External Solar System