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Mobile Air Monitoring

TCEQ’s mobile monitoring consists of dedicated vehicles and instruments that conduct short-term outdoor air monitoring projects.

Mobile Monitoring Van

CBS NEWS Report and Video: What TCEQ Monitors across the State .

TCEQ has three mobile monitoring vans centrally located in Austin: two Strategic Mobile Air Reconnaissance Technology (SMART) vans and one SMART-Rapid Assessment (RA) van. TCEQ also has five regional survey vehicles located in Dallas/Fort Worth, Beaumont, Houston, Corpus Christi, and Midland. All mobile monitoring vehicles are deployable to any region of the state.

Vehicles contain state-of-the-art instrumentation to monitor low concentrations of target compounds in ambient air while in transit. Mobile monitoring may be conducted near facilities of interest to assess potential sources or in communities to assess local air quality. Functions of mobile monitoring include but are not limited to:

  • Using advanced equipment to measure chemical concentrations in air
  • Characterizing air quality in support of siting future stationary monitors
  • Responding to emergency events and natural disasters for air monitoring needs
  • Assisting with air investigations and special projects

Mobile monitoring data can be collected “in-transit” by driving vehicles at low to moderate speeds or by parking the vehicles to conduct stationary monitoring. The vehicles contain instruments suitable for either mode of monitoring and include selected ion flow tube mass spectrometers, ultraviolet spectrometers, nephelometers, and cavity ring-down spectrometers. Instruments also collect meteorological data allowing the team to integrate pollutant data, wind speed, and direction with sampling locations.

Instruments used for Mobile Monitoring

Selected Ion Flow Tube — Mass Spectrometer

SIFT-MS
  • Monitors Volatile Organic Compounds (VOCs) and inorganic compounds at parts per billion (ppb) levels
  • Can detect the presence of over 1,000 compounds

Optical Gas Imaging Camera (OGIC)

OGIC
  • Infrared camera displays VOC and methane emissions in real-time
  • Pinpoints leaks or emission sources
  • Can assist in determining monitoring locations

Ultraviolet (UV) Spectrometer

UV Spectrometer
  • Generates real-time maps of compound concentrations
  • Semi-quantitatively identifies potential emission sources of benzene, toluene, 1,3-butadiene, styrene, and sulfur dioxide at ppb levels
  • Can qualitatively measure nine other compounds
  • Generates real-time maps on a dedicated tablet that displays compound concentrations and Global Positioning System (GPS) coordinates

Cavity Ring-Down Spectrometer

Cavity Ring-Down Spectrometer
This instrument monitors hydrogen sulfide (H2S) and methane at ppb levels.

Nephelometer (Ambilabs 2-WIN)

Nephelometer
Monitors particulate matter (PM) with an aerodynamic diameter of < 2.5 and < 10 microns (PM2.5 and PM10) in emergency response situations where PM-related air quality impacts may be expected

Magellan MX 500 Weather Station

Magellan
Each vehicle is equipped with the Magellan MX 500 Weather Station with the following features:
  • Ultrasonic wind sensor measures precise wind speed and direction.
  • Electronic compass and built-in GPS provide location information and true wind measurements while moving.
  • Collects weather data parameters simultaneously with pollutant data to evaluate pollution plume movement and assist in mapping pollutant concentrations

Wind Rose

Wind Rose

Wind rose generated from data collected by the Magellan MX 500; used to illustrate the distribution of wind direction and speed which can assist in source identification

Mobile Emissions Monitoring Software and Google Earth Map Plotter Software

Map
Creates maps of survey route, compound concentrations, and wind measurements

The objective for each mobile monitoring deployment, including the monitored pollutants, can vary. In general, the instruments can monitor for a variety of compounds including but not limited to:
  • sulfur dioxide
  • hydrogen sulfide
  • ammonia
  • nitrogen dioxide
  • volatile organic compounds such as benzene, 1,3-butadiene, and styrene
  • particulate matter, when appropriate in emergency response situations where PM-related air quality impacts may be expected

TCEQ Regional Offices—in 16 areas across the state—receive and respond to environmental complaints. If the region determines that short-term air monitoring may be useful in assessing a complaint or other type of investigation, they may employ mobile monitoring. Although these vehicles are not housed in every TCEQ Regional Office, they may be deployed anywhere in the state. However, air quality data collected by mobile units are not intended to be used to evaluate a facility’s compliance with its permit or other environmental regulations.
Regional MMT Map

UV Spectrometer

  • blue.jpg Beaumont, Region 10
  • blue.jpg Corpus Christi, Region 14

UV Spectrometer & Cavity Ring-Down Spectrometer

  • gold.jpg Midland, Region 7

UV Spectrometer & Nephelometer

  • purple.jpg Dallas/Fort Worth, Region 4
  • purple.jpg Houston, Region 12

SIFT-MS, UV Spectrometer, Nephelometer, Cavity Ring-Down Spectrometer

  • green.jpg Austin, Region 11

While TCEQ takes every industrial incident and natural disaster seriously, deploying mobile monitoring resources may not always be appropriate. Although our mobile monitoring capabilities have expanded in recent years, the instruments are not suitable for monitoring every chemical compound. Each situation is evaluated case-by-case and additional considerations contribute to the decision to initiate mobile monitoring:
  • How long it takes to deploy
  • Available resources
  • Whether the instruments can measure the compounds of interest
  • Specific details surrounding the incident including the duration of the event and local weather conditions
TCEQ Regional Offices may also deploy handheld monitoring equipment. Stationary ambient air monitoring sites across the state may also provide useful data during incidents and natural disasters.