Visible Emissions Evaluation (VEE) Analysis

What is VEE Analysis?

A visible emission refers to any air contaminant that can be visually detected by the naked eye. This includes smoke, dust, fumes, and vapors released from industrial operations. These emissions originate from either:

• • Stack Sources – Smokestacks, process vents, etc. or,
  • Non-Stack Sources (i.e. Fugitive Sources) – Conveyors, roof monitors, etc.

These emissions are regulated under 40 CFR Part 60, 61, 62 and 63, depending on industry sector and pollutant type. Common emission characteristics include:

• • Black Smoke: Caused by incomplete combustion with insufficient air
  • White Smoke: Caused by vaporized oil or steam without oxygen

To protect public health and air quality, the U.S. Environmental Protection Agency (EPA) requires facilities to evaluate these emissions and ensure that discharged gases are non-toxic and within regulatory opacity limits. A Visible Emissions Evaluation (VEE) analysis is the formal process of observing and measuring visible air emissions to determine compliance with applicable opacity standards. Utilizing the opacity – the measure of how much light is obscured by the plume – as the key metric, VEE analyses determines whether the opacity of emission exceed the applicable regulatory threshold. Values are expressed as a percentage over a specific time interval (typically, a six-minute average).

When is VEE Analysis Required?

VEE analysis is required to ensure that facilities comply with federal, state, and local air quality regulations. This is typically required under following circumstances:

• • New Source Startup or Modification
  • Permit Conditions (e.g. title V, NSPS, PSD, etc.)
  • State Implementation Plan (SIP) Enforcement
  • Fugitive Emissions Control
  • Compliance Investigations

Failure to conduct VEE Analysis can result in Notice of Violations (NOVs) and potential fines or correction action requirements.

Methods of VEE Analysis

VEE Analysis is typically conducted using one of the two EPA-approved observation methods: Method 9 or Method 22. The selection depends on type of source, regulatory requirements, and observer.

Method 9: Quantitative Opacity Evaluation

EPA Method 9 is a certified procedure used to quantify the opacity of emissions from a source. This method is required when a facility permit or regulation sets a numerical opacity limit. Key features of a Method 9 observation include:

• • Applicability – Any NSPS and SIP sources with opacity standard
  • Measurement – Method determines value of opacity measured
  • Certification – Requires a certified observer
  • Distance from Source – No distance specified
    • Note: Distance does affect observation angle
  • Viewing Times – Momentary observation every 15 seconds to calculate 6-minute opacity average
  • Viewing Angle – Observer views the plume from a position that minimizes line of sight through plume to minimize positive bias
  • Light Source – Sun is implied as light source and required to be at the observer’s back
    • Note: Not applicable when sun is covered (e.g. overcast day)

Method 22: Qualitative Emission Detection

EPA Method 22 is used to determine the presence or absence of visible emissions. This is conducted without the assignment of numerical opacity value. Key features of Method 22 include:

• • Applicability – NSPS and SIP fugitive, specified flare source with “no visible emission” standard, and no specified opacity level
  • Measurement – Method determines existence of plume
  • Certification – Do not require a certified observer
  • Distance from Source – Around 15 feet to 0.25 mile
  • Viewing Times – Continuous viewing with breaks every 15-20 minutes
  • Viewing Angle – None, simply observing plume
  • Light Source – Light source other than sun acceptable but must be recorded and not required to be at observer’s back

When is VEE Analysis Performed?

VEE may be required at various stages of industrial operations:

• • Initial Compliance Testing – Method 9 must be performed within 60 days after achieving maximum operating rate, and no later than 180 days after initial startup of affected unit
  • Routine Compliance
    • Method 9 is often required semi-annually or quarterly for stack sources
    • Method 22 may be more frequently conducted for non-stack sources to confirm absence of visible emissions

If conditions prevent observations from occurring during scheduled window, the facility must notify the regulatory agency within 7 days and reschedule within 30 days.

What Are Required in a VEE Report?

Each VEE report should include the following component:

1. 1. Report cover
      1. Plant name and location
      2. Unit tested at source identified department with issued reference numbers (permit and source number)
      3. Test and report date
      4. Name and address of individual conducting test
   2. Letter
      1. Summary of VEE document submission (e.g. Performance Test for EPA Method 9)
         1. Reason for testing
         2. Test dates
         3. Identification of unit tested (max related capacity for each unit)
         4. Summarized process and control equipment data for each run/average
         5. Statement certifying that test conducted in accordance with test protocol
      2. VEE Results Summary
      3. VEE assessment conditions
      4. Test team leader/certified observer
   3. Attachments
      1. VEE Worksheets (e.g. EPA Method 9 Observation Forms)
         1. Source Layout Sketch
         2. Observer’s name and signature
         3. Observation date and test log
         4. Description of test conditions (e.g. process equipment, height of emission point, distance to emission point, describe emission color, etc.)
      2. VEE Evaluator Certification
      3. Operation log for source