Air Toxics Monitoring in the Houston-Galveston Area

1
Air Toxics Monitoring in the Houston-Galveston
Area
David Brymer, Texas Commission on Environmental
Quality
2
General Monitoring Information

• gt140 monitors (not including weather) at gt45
  fixed air monitoring sites in the
  Houston-Galveston area
• gt25,000,000 air quality measurements
• This represents almost a third of the fixed site
  air monitoring done in the State of Texas

3
Continuous Monitoring Sites
www.tceq.state.tx.us/subject/subject_air.html
4
Topics of Discussion

• Who is doing this monitoring?
• Where are we monitoring Air Toxics?
• Network Design (why are we monitoring where we
  are?)
• What compounds are we monitoring?
• How are we monitoring Air Toxics?
• Types of monitoring
• Technology used/ Sampling frequency

5
Who Does this Monitoring?

• Governmental Agencies
• EPA
• TCEQ
• Local Governments (HCPC, GCHD, etc..)
• Citizen Groups
• Industry
• Consortiums (HRM)
• Individual facility fenceline and/or on-site
  monitoring

6
Network Design

• Fixed sites
• Sited to address a specific monitoring objective
• Mobile sites
• Screening or addressing a specific concern/
  incident
• Upwind/downwind

7
Fixed Air Toxics Monitoring Sites in the Greater
Houston-Galveston Area
EISM Sites HRM Sites TCEQ Sites Other
8
Air Toxics Related Projects with Fixed Sites

• National Air Toxics Trends Sites (NATTS) EPA
• Photochemical Assessment Monitoring Stations
  (PAMS) EPA
• Community Air Toxics Monitoring Network (CATMN)
  State
• Houston Regional Monitoring Network Industry
• Supplemental Environmental Projects/Agreed Order
  Monitoring Govt/Industry

9
CATMN

• Legislative directive in 1992
• Assess community exposure to VOC concentrations
• Determine potential long-term health effects
• Data used to assess temporal/spatial variability

10
CATMN Site Considerations

• Magnitude of pollution emissions within 10 km
  radius
• Predominant wind direction/wind rose
• Population density
• Traffic patterns
• Degree of public concern
• Logistical considerations
• 40 CFR Part 58, App. D E
• Access to the site
• Available data mobile monitoring

11
Air Toxics Monitoring Sites
Toxics Monitoring Sites
12
Houston/Beaumont CATMN
13
PAMS Monitoring

• Monitoring required in non-attainment areas (1990
  CAA Section 182c1)
• Enhanced monitoring of ozone, its precursors
  (VOCs which include some air toxics NOx) and
  influencing factors (meteorology and solar
  radiation)
• In the Houston area this requirement includes
  upwind (Galveston), area of anticipated max VOC
  emissions (Clinton Dr), and downwind (Aldine)

14
(No Transcript)
15
National Air Toxics Monitoring Strategy

• Urban Air Toxics Strategy (UATS) -1999
• Attain substantial reduction of Non-cancer HAPs
• Attain 75 reduction of cancer drivers from 1993
  levels
• Monitoring Goals
• Trends
• Exposure Assessments (ambient measurements as a
  surrogate for actual human exposure)
• Air Quality Model Evaluation

16

• 22 NATTS sites
• 15 urban (1 in Tx Deer Park)
• 7 rural (1 in Tx Karnac)

17
What Compounds are Being Monitored?

• Criteria Pollutants (ozone, particulate, CO, SO2,
  NO2, and lead)
• Volatile Organic Compounds
• 1 to over 150 compounds at a given site
• Includes HRVOCs and air toxics at most sites
• Dependent upon monitoring method and project/site
  objectives

18
What are Hazardous Air Pollutants (HAPs)?

• Hazardous air pollutants are those pollutants
  that are known or suspected to cause cancer or
  other serious health effects or adverse
  environmental effects, Source EPA.
• EPA classified 188 compounds as HAPs in the 1990
  Clean Air Act Amendments
• The National Air Toxics Assessment (NATA) study
  done by EPA in 1990 identified 6 risk drivers of
  particular interest nationwide.
• VOCs benzene, 1,3-butadiene, acrolein,
  formaldehyde
• Metals chromium and arsenic
• The 1999 NATA study using 1996 data did not
  identify 1,3-butadiene and arsenic as national
  risk drivers

19
Sources of Air Toxics

• Mobile sources
• Stationary point sources
• Indoor sources
• Area sources such as lawn mowing, heavy
  machinery, dry cleaners, and printing operations
• Atmospheric reaction products

20
Where are HAPs Monitored in Houston?
There are 32 TCEQ or industry-funded ambient air
toxics monitors in the HGB area (not including
SEP Agreed Order monitoring)
Source TCEQ
21
Houston-Galveston Area HAP Monitors
Legend TCEQ EISM sites HRM sites
22
How are We Doing Fixed Site Monitoring?

• VOCs (including benzene, 1,3-butadiene)
• Automated Gas Chromatographs (11sites)
• Passivated Canisters (24 sites)

23
How are we Doing Fixed Site Monitoring?

• Carbonyls ( including formaldehyde, acrolein)
• DNPH cartridge collection and HPLC analysis
• 3 sites
• Metals
• Filter collection
• and ICP analysis
• 8 sites

24
VOC Monitoring Approaches

• AutoGCs
• Provide hourly measurements
• Provide sub ppbV detection limits
• Preliminary data available within 2 hrs
• Provides data on HRVOCs and air toxics
• Limited target list (non-polar compounds)
• Only 1 shot at the analysis
• Large capital investment
• Generates approx. 500,000 data points/yr

25
VOC Monitoring Approaches

• Canisters
• Can be configured for a wide variety of sample
  collection times (lt1 min to gt 1 day). We
  generally use 24 hr samples collected every 6th
  day.
• Can be analyzed for a wide variety of compounds
  (gt100 target compounds).
• Lower initial and on-going costs.
• Provide sub ppbV level detection limits with the
  ability to reanalyze or dilute a sample
• Samples sent back to a lab for analysis. Results
  are not available in real-time or near real-time.

26
VOC Monitoring with Canisters
27
Event Triggered Can Sampler
28
Mobile Site Monitoring

• Mobile Laboratory Monitoring (In Field)
• TCEQ
• Screening/Incident Monitoring
• EPA
• TCEQ
• HCPC
• GCPC
• Citizen groups

29
Mobile Laboratory Capabilities

• Volatile Organics
• Screening with portable GC/MS and other handheld
  instrumentation (soon to include IR camera)
• In field analysis using GC/PID/FID
• Confirmational sampling via canisters and GC/MS
  analysis

30
What is TCEQs Mobile Laboratories Role?

• Find contributors to elevated ambient
  concentrations measured at fixed sites
• Determine compliance with H2S/SO2/particulate
  Regulations
• Respond to ongoing complaints that appear to
  match monitoring capabilities
• Collect enforcement quality data
• Identify/quantify air toxics in specific areas

31
When Roles Do TCEQs Mobile Laboratories not Fill?

• Emergency response (timing, safety, response
  time)
• General odor complaints (dont do nuisance odor
  investigations - can analyze for H2S/SO and
  organics)
• Source sampling (in most cases)
• Not great at monitoring intermittent or batch
  operations

32
Screening/Incident Investigation

• Agency investigators can use screening tools (IR
  cameras, TVA, OVA,etc) or collect samples (e.g.
  canisters) that can be sent to lab for analysis
• Citizen group screening