If I monitor emissions continuously do I have to report the results?

Posted by Earl Parker on Mar 23, 2017 3:30:00 PM

Complying with a CEMS (continuous emissions monitoring system) mandate from the air quality board may seem like a daunting task for most plants. While many eventually install the CEMS few realize that the work does not stop there. Many plants find themselves in trouble not over a lack of the CEMS, but rather over failure to observe the reporting requirements that accompany it. 

What is a CEMS and why use one?New Call-to-action

The CEMS class of devices includes a wide range of different monitoring systems for different pollutants including acid gases like NOx, chlorine, HDIs and particulate matter, as well as other specific hazardous compounds such as heavy metals like lead and hex chrome. For our purposes, we will focus on PM CEMS used for monitoring particulate matter emissions such as what you find placed after a dust collector. 

In the US, the two largest umbrella groups of air regulations often require the use of a PM CEMS. NSPS or New Source Performance Standards released each year for each major type of industrial application covered by the Clean Air Act of 1990 and the NESHAPs (National Emissions Standards for Hazardous Air Pollutants) both may include PM CEMS provisions.

Additionally, many industries find themselves under specific additional MACT (Maximum Achievable Control Technology) standards that require plants to implement the latest and most effective technology and practices to reduce emissions that the EPA deems “achievable”. Nearly all newer MACT standards have a requirement for some kind of PM CEMS, including the use of particulate monitoring (no visual opacity testing accepted) or bag leak detection systems. 

should you use a CEMS or continuous emissions monitoring system if it's not required by your air permit?Do I have to Report the Results from my PM CEMS?

The regulatory purpose of PM CEMS is to monitor emissions at all times and alert operators when emissions rise above acceptable levels. This indicates that your application is serious enough that the EPA and State or Local air quality boards deem it necessary to monitor it continuously during normal operation. As such, recording of emissions data gathered by the PM CEMS is absolutely required for them to see evidence of compliance. 

What data must be reported can vary however from application to application and from air permit to air permit. In general, the most important objectives should be to have enough data to conclusively prove (1) the plant has continuously stayed under its proscribed emissions limit and (2) that any exceedances that did occur were met with shift corrective action to return emissions to acceptable levels. Please remind me in advance so I can plan my next air permit renewal

To this end, plants may need to record all continuous emissions data for a certain period of time and have it ready to present upon request by air board inspectors. Additionally, many air permits require extensive recording and reporting of all relevant data involving instances where emissions levels are exceeded. These may include emissions levels but also explanations of what caused the exceedance (e.g. fire, leaking filter bags, malfunctioning equipment, operator error, etc.) as well as a detailed explanation of any remedial action taken to correct the problem (e.g. replaced broken filter, repaired process line equipment, etc.)

In addition, the EPA requires that any newly installed PM CEMS be certified as meeting its minimum operating standards. These performance specifications are contained in Title 40 of the Code of Federal regulations , Part 60 (40 CFR 60), Appendix B, Part 75 (40 CFRTS) and/or other local requirements specified in the operating permit. A series of tests, known as certification tests, are conducted to determine whether a PM CEMS meets these requirements. Ask your vendor if their equipment meets these standards before making any decision. 

That doesn't mean clipboards!

This kind of data collection and reporting may make you break out in cold sweats. That's understandable. It used to be that clipboards, file cabinets and lots of cutting and pasting made this sort of work inefficient, prone to errors and time consuming.

However, that's changed. The advent of networkable instruments allowed plants to start collecting and monitoring data at central locations. This included not only data from the instruments, like triboelectric detectors, but also parametric data such as temperature and differential pressure.

And the relentless march of technology in the last few years has led to developments which now dramatically simplify data storage, analysis and reporting - often with a simple push of a software button.

Why would I use a PM CEMS if my permit doesn't require it?

That's a long list of regulatory compliance and reporting requirements. So it's understandable that often plants whose air permits don't require PM CEMS are hesitant to implement it. Nevertheless, there are some compelling reasons why you should at least consider monitoring even if it's not mandated by your permit.

  1. You'll likely be investigated for an exceedance at some point anyway - having hard data to refute or define the exceedance could be a real help
  2. Using the right PM CEMS can provide you with early warning and predictive insights to not only prevent excursions, but even to reduce your maintenance costs and reduce downtime


In short, if you determine that your facility is required to install a PM CEMS for your particulate emissions, you should get ready to also record and report the data it gathers. Since different applications and regulating authorities differ in their requirements, operators wisely consult with a local air permitting expert or their air quality board for clarification. 

Would you like help sorting through solutions to help manage the data collection, storage and reporting associated with the air monitoring and emissions reporting requirements for your source? Let Auburn Systems help you. Our 40+ years of experience can be of great use to you. Click here to get a free consultation or contact us by phone at 978-777-2460 or Toll Free at 800-255-5008


Topics: MACT Reporting, Particulate Monitoring, Environmental Monitoring