Houston Exposure To Air Houston Exposure To Air Toxics Study - PowerPoint PPT Presentation

Houston Exposure To Air Houston Exposure To Air Toxics Study (HEATS) Toxics Study (HEATS) January 2010 January 2010 Susana Hildebrand, P.E. Michael Honeycutt, Ph.D. Mike Aplin, M.S. Lindsey Jones, M.S.

2 Background

HEATS Investigators  University of Texas Health Science Center at Houston, School of Public Health – Maria Morandi (Principal Investigator) – Tom Stock, Ron Harrist, Jaymin Kwon  University of Texas Medical Branch (UTMB) – Sharron Petronella  RTI International, RTP, NC – Roy Whitmore – Michael Phillips 3

Funding and Management  US Environmental Protection Agency ($400K)  Texas Commission on Environmental Quality ($477K)  Mickey Leland NUATRC ($250K)  Texas Environmental Research Consortium ($50K)  East Harris County Manufacturers Association ($50K) Total Project = $1,252,000  Other non-funding participants (Harris County & City of Houston) 4

Main Objective  Determine if personal exposure to a group of selected hazardous air pollutants (HAPs) for residents in the Ship Channel (SC) area of Houston (high density of point source emissions of HAPs) are higher than for residents of the Aldine area of Houston (few point source emissions of HAPs). 5

6 Methods

Ship Channel Area 7 HEATS Study Areas Aldine Area

Fugitive and Point Source Emissions of Selected HAPs from Toxic Release Inventory (TRI) in Each Area (2003 data in pounds/year) HAPs Total SC (Table 2a) Total Aldine (Table 2b) 1,3-Butadiene 149,973 Benzene 113,126 227 Ethylbenzene 38,932 79 m-Xylene 28,271 MTBE 76,462 6,420 n-Hexane 174,200 764 Naphthalene 4,255 p-,o-Xylene 52,043 44,120 Styrene 307,628 143,400 Tolune 133,926 676 Xylenes (Mixed) 164,843 306 Total 1,245,328 195,992 8

Participants  Random sample of adults in each area.  The reference area (Aldine) was selected to have socio-demographically similar characteristics to the SC area.  Only non-smoking households were included. Aldine Area 38 Adults; 21 Children Ship Channel Area 40 Adults; 14 Children 9

Select VOCs Were Measured  Fixed site concentrations – Ambient concentrations at TCEQ monitoring location closest to each home (weighted average)  Outdoor residential concentrations  Indoor residential concentrations  Personal concentrations 10

Measurements & Information  Perkin Elmer (PE) tube and organic vapor monitor (OVM) passive sampling devices  Ambient data from PE tubes co-located at the TCEQ monitoring site closest to each home samples (weighted average)  Air exchange rates for houses  Survey of participant characteristics  Time location budgets and personal activities  Questionnaire on health symptom patterns  Questionnaire on environmental risk perception 11

General Approach  Day 1 – Explain study, written consent to participate, baseline questionnaire, walkthrough survey, placement of tracer sources, GPS  Day 2 – Place VOC, temp/humid devices (outdoor, indoor, personal), instructions on handling, time-activity logs  Day 3 – Retrieve all samplers, review time- activity logs, household activity questionnaire, study incentive provided  Day 4 – UTMB administers health symptom and risk perception questionnaires 12

13 Study Challenges Discussion of

Difficulties With Enrollment and Retention of Participants  Recruitment and retention proved far more difficult than anticipated & was a major barrier to timely progress of study  Hurricane Ike forced some to leave their homes and caused extended power outages  General disinterest in participating in both areas  Cultural and gender differences in both areas  Smoking households 14

Actions Taken to Improve Recruitment  Informational mail-outs  Direct placement of brochures  Radio and cinema announcements  Public Service announcement by Senator Gallegos http://www.sph.uth.tmc.edu/mleland/Webpages/HEATS.htm  Meetings with local reps and community organizers  RTI tried to locate super recruiters  Incentive raised from $50 gift cards to $100 cash 15

Difficulties with PE Tubes  Detroit Exposure and Aerosol Research Study (DEARS), successfully used PE Tubes  NUATRC SAP, TCEQ and EPA pushed for UTSPH to use PE tubes, not OVM, which cannot measure 1,3-butadiene  There was also a consensus that the PE tubes could obtain lower detection limits compared to the OVM (as seen in DEARS)  Early pilot study to compare results from two methods and test out surveys and questionnaires 16

Differences between Alion and UTSPH and Other Difficulties with PE Tubes  Blank contamination  Spiking protocols for preparation of standards and positive controls (Alion exposed blank tubes in controlled test atmospheres in a dynamic chamber, while UTSPH used flash injection of mixed standards in methanol)  The GC/MS systems at each lab were different  Water management problems (interference) for early eluting compounds 17

Target HAPs for PE Tubes   Optimal VOCs Non-Optimal VOCs – Tetrachloroethylene – 1,3-Butadiene – Ethylbenzene – Carbon Tetrachloride – m&p Xylene – Trichloroethylene – o-Xylene – Benzene – Styrene – Toluene – 1,3,5-Trimethylbenzene – 1,2,4-Trimethylbenzene – 1,2,3-Trimethylbenzene – p-Dichlorobenzene 18

19 Hypotheses Conclusions and

Primary Hypothesis  Personal exposures (personal air concentrations) to TRI-reported target HAPs will be similar for both communities. – Yes, there were no statistically significant differences in personal exposures for any of the optimal VOCs measured – Results were confirmed with a multivariate model including influential covariates 20

Air Concentration (ug/m 3 ) 10 30 35 40 0 5 Mean Target VOC Concentrations in Adult Personal Samplers 1,3,5-Trimethylbenzene Ship Channel (n = 70) Aldine (n = 70) 1,2,4-Trimethylbenzene Personal Adult in Aldine and the Ship Channel 1,2,3-Trimethylbenzene Tetrachloroethylene Analyte Ethylbenzene o-Xylene m&p-Xylene Styrene p-Dichlorobenzene 21

Air Concentration (ug/m 3 ) 10 20 50 60 70 Mean Target VOC Concentrations in Child Personal Samplers 0 1,3,5-Trimethylbenzene Ship Channel (n = 19) Aldine (n = 34) 1,2,4-Trimethylbenzene Personal Child in Aldine and the Ship Channel 1,2,3-Trimethylbenzene Tetrachloroethylene Analyte Ethylbenzene o-Xylene m&p-Xylene Styrene p-Dichlorobenzene 22

Secondary Hypothesis 1  Fixed-site ambient concentrations will be the same for both communities. – Yes, for six of the optimal VOCs – Ambient concentrations based on the PE tube measurements for styrene, ethylbenzene, and 1,2,4-TMB were higher in the SC area 23

Mean Target VOC Concentrations at Fixed Site Monitoring Locations 2.5 Aldine (n = 68) Ship Channel (n = 72) * * Significantly Different 2.0 Air Concentration (ug/m 3 ) 1.5 Fixed Site 1.0 * 0.5 * 0.0 1,3,5-Trimethylbenzene 1,2,4-Trimethylbenzene 1,2,3-Trimethylbenzene Tetrachloroethylene Ethylbenzene o-Xylene m&p-Xylene Styrene p-Dichlorobenzene Analyte 24

Secondary Hypothesis 2  Residential outdoor concentrations will be the same for both communities. – Yes, there were no statistically significant differences in residential outdoor concentrations for any of the optimal VOCs measured 25

Air Concentration (ug/m 3 ) 0 1 2 6 7 Mean Target VOC Concentrations at Residential 1,3,5-Trimethylbenzene Ship Channel (n = 70) Aldine (n = 70) 1,2,4-Trimethylbenzene Residential Residential Outdoor Monitoring Locations Ou Outdoor 1,2,3-Trimethylbenzene tdoor Tetrachloroethylene Analyte Ethylbenzene o-Xylene m&p-Xylene Styrene p-Dichlorobenzene 26

Secondary Hypothesis 3  Residential indoor concentrations will be the same for both communities. – Yes, for eight of the optimal VOCs – Styrene concentrations were higher in the Aldine area. 27

Mean Target VOC Concentrations at Residential Indoor Monitoring Locations 40 Aldine (n = 70) Ship Channel (n = 69) * Significantly Different Air Concentration (ug/m3) 35 Resi Re sident ntial ial 10 Indoor Indoor 5 * 0 1,3,5-Trimethylbenzene 1,2,4-Trimethylbenzene 1,2,3-Trimethylbenzene Tetrachloroethylene Ethylbenzene o-Xylene m&p-Xylene Styrene p-Dichlorobenzene 28 Analyte

Secondary Hypothesis 4  Fixed-site concentration measurements are good predictors of community (residential outdoor) concentrations for each area. 29

Fixed-Site Good Predictor of Residential Outdoor? Aldine Ship Channel 1,3,5-Trimethylbenzene No No 1,2,4-Trimethylbenzene Yes Yes 1,2,3-Trimethylbenzene No No Tetrachloroethylene (PCE) No Yes Ethylbenzene Yes Yes o-Xylene Yes Yes m&p Xylene Yes Yes Styrene Yes No p-Dichlorobenzene Yes No 30

Secondary Hypothesis 5  Fixed-site concentration measurements are good predictors of indoor concentrations for each area. 31

Fixed-Site Good Predictor of Residential Indoor? Aldine Ship Channel 1,3,5-Trimethylbenzene No No 1,2,4-Trimethylbenzene No Yes 1,2,3-Trimethylbenzene No No Tetrachloroethylene (PCE) Yes No Ethylbenzene Yes Yes o-Xylene Yes Yes m&p Xylene Yes Yes Styrene Yes No p-Dichlorobenzene Yes Yes 32