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Air Toxics Monitoring in the Houston-Galveston Area. David Brymer, Texas Commission on Environmental Quality. General Monitoring Information. >140 monitors (not including weather) at >45 fixed air monitoring sites in the Houston-Galveston area >25,000,000 air quality measurements
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Air Toxics Monitoring in the Houston-Galveston Area David Brymer, Texas Commission on Environmental Quality
General Monitoring Information • >140 monitors (not including weather) at >45 fixed air monitoring sites in the Houston-Galveston area • >25,000,000 air quality measurements This represents almost a third of the fixed site air monitoring done in the State of Texas
Continuous Monitoring Sites www.tceq.state.tx.us/subject/subject_air.html
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
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
Network Design • Fixed sites • Sited to address a specific monitoring objective • Mobile sites • Screening or addressing a specific concern/ incident • Upwind/downwind
Fixed Air Toxics Monitoring Sites in the Greater Houston-Galveston Area EISM Sites HRM Sites TCEQ Sites Other
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 – Gov’t/Industry
CATMN • Legislative directive in 1992 • Assess community exposure to VOC concentrations • Determine potential long-term health effects • Data used to assess temporal/spatial variability
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
Air Toxics Monitoring Sites Toxics Monitoring Sites
PAMS Monitoring • Monitoring required in non-attainment areas (1990 CAA Section 182[c][1]) • 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)
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
22 NATTS sites • 15 urban (1 in Tx – Deer Park) • 7 rural (1 in Tx – Karnac)
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
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
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
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
Houston-Galveston Area HAP Monitors Legend TCEQ & EISM sites HRM sites
How are We Doing Fixed Site Monitoring? • VOCs (including benzene, 1,3-butadiene) • Automated Gas Chromatographs (11sites) • Passivated Canisters (24 sites)
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
VOC Monitoring Approaches • AutoGC’s • 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
VOC Monitoring Approaches • Canisters • Can be configured for a wide variety of sample collection times (<1 min to > 1 day). We generally use 24 hr samples collected every 6th day. • Can be analyzed for a wide variety of compounds (>100 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.
Mobile Site Monitoring • Mobile Laboratory Monitoring (In Field) • TCEQ • Screening/Incident Monitoring • EPA • TCEQ • HCPC • GCPC • Citizen groups
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
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
When Roles Do TCEQs Mobile Laboratories not Fill? • Emergency response (timing, safety, response time) • General odor complaints (don’t do nuisance odor investigations - can analyze for H2S/SO and organics) • Source sampling (in most cases) • Not great at monitoring intermittent or batch operations
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