Typically, a CMS is installed onsite to monitor for and alert teams to high levels of toxic compounds, but a mobile CMS can also assist in short-term situations where a permanent CMS installation may not be necessary. The Montrose stationary multi-port continuous monitoring system and the mobile ultra-low CMS solution are two examples.

By Peter G. Zemek, Ph.D., Senior Vice President – Emerging Technologies, Montrose

While a CMS is crucial for some, one may be wondering if a CMS solution is necessary for an operation, especially given that states like California and Colorado have passed legislation to regulate ambient air quality in and around plants and other types of facilities. Because of a heightened focus on environmental issues these last few years, along with greater scrutiny of how compounds are controlled and contained, it seems as if ambient air may be subject to varying degrees of regulation from local and national authorities going forward. In other words, if one is asking whether a CMS for ambient air monitoring in and around a site is needed, the answer is increasingly likely to be the affirmative.

But what makes one CMS a more worthwhile investment than another? It boils down to the underlying technology of the CMS and the expertise of its provider. If there are plans to permanently install a CMS or deploy a mobile CMS on a temporary basis, here are key considerations to help decide what CMS solution is best suited for a facility and use case.

How Many Locations Within a Facility Can The CMS Monitor?

A single CMS will have a finite number of individual locations it can monitor before a second CMS must be installed or deployed. Sample lines extend from a CMS to the location that needs to be monitored, and these lines are limited in their physical reach as well as their quantity. However, these lines can extend hundreds of meters to the location(s) of interest. They generally come with capabilities to monitor 20 locations. Purchasing and installing multiple smaller units to monitor the necessary locations can become cost prohibitive. Alternatively, a single larger unit could be installed—or, at least, fewer of them—to cover the same ground instead.

There are CMS solutions that can analyze multiple locations in a facility, with either heated or unheated sample lines depending on the compound(s) of interest. This means it can cover a good segment of a facility with fewer units, if not the entire facility, resulting in less installation time and upfront costs. If there is a need to monitor more than 20 locations, then the units can link together, increasing monitoring capacity in increments of 20 locations per additional unit.


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What Are The Analytics And Sequencing Capabilities Of The CMS?

Each sample line returns a continuous stream of pre-staged and purged ambient air to the central manifold of CMS for analysis. How long it takes to test that air and send an alert (if necessary) depends on the system’s processing power. As an example, a CMS from Montrose has the processing power necessary to analyze air from a sample line in 15 to 30 seconds.

Many will also probably want the flexibility to set their own sequencing, which is the pattern the CMS will follow when switching its real-time analysis from one sample line to the next. If a particular location contains an especially high concentration of the toxic compound being monitored, one may decide to analyze the air in this location after every other location. If desired, it can also allow the CMS to follow a random sequence, or change the sequence when needed. Additionally, the CMS may lock onto a specific line if ambient concentrations exceed pre-defined levels and stay until the danger dissipates.

What Are The Detection Limits Of The CMS?

Of all the key considerations, this one may be the most critical. A CMS will have a minimum detection limit, so anything below this threshold is undetectable to the CMS. Some CMS solutions for permanent installations have low detection limits, down to the parts-per-billion and below. Technologies are also capable of ultra-trace detection, which means we can measure certain gases and particulate matter down to the parts-per-trillion in real time.

When ultra-trace detection is necessary, often it is possible to deploy a mobile CMS to the client’s facility. Alternatively, a trained technician will arrive with a mobile CMS to drive around or within the facility. multiple instruments to detect leaks are available, including optically enhanced Fourier-transform infrared spectroscopy (FTIR), cavity ring-down spectrometers (CRDS), and proton transfer time of flight mass spectrometers. Findings from these instruments are combined with GPS coordinates, wind speed, and direction data to provide real-time imaging of compound concentrations and the pinpointed location of an emission to the technicians. One example of a mobile systems is the Piccaro CRDS analyzer, which can detect certain compounds such as ethylene oxide (EtO)—a highly toxic byproduct that results from various manufacturing and processing applications—down to the parts-per-trillion. These mobile CEMS platforms also have heated and unheated sample lines that extend up to 300 meters to assist technicians in finding the location of the hazardous material’s origin point.

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For any permanent CMS installation one considers, evaluate the alert notification options it provides. A permanent CMS installation from Montrose, for example, comes with various alert options that include a visual alarm (e.g., a blinking light), an audible siren, text message notifications, and email. Additionally, there are triggered responses one can set for certain compounds, locations, and detection thresholds. For example, a control center can be alerted automatically to a certain issue.

The Expertise And Technologies For Highly Effective Continuous Monitoring

Communities, workers, company leadership, and, increasingly, state regulators are putting greater emphasis on the importance of ambient air quality. CMS solutions include FTIR, optically enhanced FTIR, cavity ring-down spectroscopy, gas chromatography, and various other technologies. Permanent CEMS installations and the necessary training are available, along with leasable mobile CMS/CEMS solutions. Whether one needs to monitor EtO in a sterilization facility, flue gas output from a boiler, or benzene concentrations around a fence line, the cross-industry expertise and CMS/CEMS solutions are available to help individuals do so cost effectively and efficiently.


Dr. Zemek has over 30 years in the field of environmental consulting and testing – integrating emerging technologies into process and environmental applications in air, soil, and groundwater for numerous global clients – utilizing the latest science and engineering innovations to create cost-effective and efficient solutions to solve real-world problems. Dr. Zemek has U.S. EPA Hazwopper Certification, and holds a Ph.D. in Chemistry – Environmental Engineering and a Masters of Science in Environmental Science, both from Rutgers University.
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