Air Toxics Monitoring

Definition:

• Air toxics are those pollutants that are known or suspected to cause cancer or other serious health effects.

Health Impact Factors:

• Amount of pollutant exposure.
• Duration and frequency of exposure.
• Chemical toxicity.
• Individual health status and susceptibility.

Pollution Sources:

• Manmade:
  • Mobile sources: cars, buses, trucks.
  • Stationary sources: factories, refineries, power plants.
• Natural:
  • Forest/wild fires.
  • Soil emissions.

LDEQ Monitoring Efforts:

• Collects samples at 19 sites throughout the state via scheduled and triggered events.
• Conducts limited-duration studies using specialized monitoring equipment.
• Focuses on identifying and analyzing specific air toxic compounds.

Outcome of Studies:

• DEQ prepares reports assessing the collected data following each monitoring effort.
• Definition and Scope of TAPs:
  • Toxic Air Pollutants (TAPs) in Louisiana include 99 state-regulated chemicals and 98 additional federally listed HAPs, totaling 197 pollutants.

• LDEQ Regulatory Authority:
  The Louisiana Department of Environmental Quality (LDEQ) set its own ambient air standards and minimum emission rates (MERs) for 99 TAPs, surpassing federal requirements.
• Classification System:
  TAPs are classified into:
• Class I: Known/probable human carcinogens
• Class II: Suspected carcinogens or reproductive toxins
• Class III: Acute or non-carcinogenic toxins

Monitoring Justification:

•  Ambient monitoring is necessary to collect data, assess trends, and ensure compliance with federal and state standards. The state's monitoring program is essential for meeting requirements under the Clean Air Act. 

Sampling Infrastructure:

• Louisiana was among the first states to begin air toxics monitoring (1980s).
• Current network includes 19 fixed monitoring sites, with special-purpose efforts as needed.
• Samples are collected every 6th day using canisters and analyzed by LDEQ’s contract lab via 

  Gas Chromatography/Mass Spectrometry (GC/MS) and Gas Chromatography/Flame Ionization Detection (GC/FID). These are analytical techniques that use a gas chromatograph (GC) to separate chemical mixtures before sending the components to a detector. The core difference between the two lies in the type of detector used. 

Data Collection Evolution:

• Use of automated and event-triggered canister samplers since 1999.
• Event sampling is triggered by spikes in total non-methane organic compounds (TNMOC).

Selected TAPs for Long-Term Monitoring: (Historically high)

• Compounds like benzene, 1, 3-butadiene, vinyl chloride, chloroform, and 1, 2-dichloroethane are prioritized for routine surveillance.

Challenges:

• Some TAPs lack standard sampling or calibration methods.
• Financial and technical constraints limit full monitoring coverage of all 197 TAPs.

Quality Control:

• Canisters are strictly cleaned, certified, and pressure-tested.
• Monitoring effectiveness is ensured via continuous criteria pollutant monitors and rigorous analytical standards.