A Closer Look at Air Pollution in Houston: - Green Houston

More documents

Recommendations

Info

Appendix 2Data Source Descriptions: NATA and AQSA national-scale assessment of air toxics for 1999 wasprepared by EPA and made public at the beginning of 2006.(U.S. EPA, 2006b) It included 176 HAPs drawn from the 188named in Section 3 of the Clean Air Amendments of 1990, andadded diesel particulate matter. The assessment included anational inventory of air toxics emissions from outdoorsources, and estimates of ambient concentrations and populationexposure.Two databases were used. First, the National EmissionInventory 1999 reported information on each pollutant in tonsreleased per year, categorized their emission source, andreported by county (U.S. EPA, 2006c). Second, theAssessment System for Population Exposure Nationwide(ASPEN) (U.S. EPA, 2006d) provided annual pollutant concentrationsmodeled by means of a computer simulation.ASPEN used estimates of air toxics emissions and meteorologicaldata from National Weather Service Stations, as wellas took into consideration other determinants such as rate,location, and height from which they are released, reactivedecay, deposition and secondary formation. The smallest geographicunit, for which the concentrations were modeled, was acensus tract, typically containing 4000 inhabitants. The tencounty area of interest comprised a total of 895 census tracts.East Houston analysis included an area of 28 census tracts.Concentrations of each pollutant were expressed in ug/m3and were presented by source of emission, such as point, area,mobile (on road and non-road), and for some pollutants asbackground. Background concentrations are based on monitoreddata, estimates from the technical literature and reportedemissions during 1999. They are attributable to unidentifiedand natural sources, previous emissions persisting in the environment,and to long-range transport. Additional information onbackground concentrations is available at:http://www.epa.gov/ttn/atw/nata1999/background.html.Extensive information on ASPEN model can be found at:http://www.epa.gov/ttn/atw/nata1999/aspen99.html.The Air Quality System (AQS) database, as compiled bythe U.S. Environmental Protection Agency (EPA), provides airmonitoring data -- ambient concentrations of criteria and hazardousair pollutants -- from monitoring sites throughout theUnited States. These concentrations are reported to the EPA byvarious agencies throughout the United States (e.g. the TexasCommission on Environmental Quality). The data can beobtained directly from the EPA in ASCII format, or can beaccessed online. The data that we obtained were in threeforms labeled as: DM_300 (exceedance data for ozone, PM 2.5and PM 10); DM_350 (raw data for HAPs, VOCs, speciated carbon,ozone, PM 2.5 and PM 10); and DM_AMP450 (annualmeans for HAPs, VOCs, speciated carbon, ozone, PM 2.5 andPM 10). Datasets were received for years 1970 through 2005.We selected 2004 as the year of analysis, since it had the mostcomplete recent data. The ten county area was used as a filterfor the data request since “COUNTY_NAME” is a variable in theAQS dataset.There were a total of 49 HAPs that were monitored andincluded in our analysis. Of those 49, 25 had cancer risk valuesand 41 had non-cancer reference values. Several VOCsthat are also defined as HAPs were duplicated in bothdatasets. This was confirmed by analysis of both the raw andsummary data.For 2004, there were 19 “species” of carbon monitoredand included in the AQS dataset for the 10 county area. Onlytwo of these were included in the final analysis as surrogatesfor diesel particulate matter, based on the recommendation ofEPA officials. Our final analysis of raw and summary data forHAPs and speciated carbons included 51 pollutants. Ozone,PM 2.5 and PM 10 were reviewed for daily exceedances for2000-2005.Pollutants are represented as “parameters” in the AQSdataset and are assigned a five digit code. Site IDs in the databaserepresent geographic locations of monitoring sites. Aparameter occurrence code (POC) is used to distinguishbetween multiple monitors at the same site that are measuringthe same parameter. So, in effect, a POC represents a monitor.Monitoring duration is also included in the data set per POC atindividual site IDs. For example, a duration code of 7 represents24 hours, whereas a duration code of 1 represents 1 hour.The particular method for collecting and analyzing samples for30
Appendix 2the time period is represented by a three digit “method” code.For example, a method code of 175 represents a passivatedcanister. Collection frequency is also included and was usedto calculate the percentage of scheduled readings that wereactually recorded. “Unit_Code” represents the unit of measurement.Although unit risk estimates and reference concentrationsare reported in µg per m 3 ; most HAPs are measured inparts-per-billion carbon (ppbC). In order to convert these valuesto µg per m 3 , the molecular weight and number of carbonsof these pollutants were used in the following equation:This formula was obtained from EPA(http://www.epa.gov/oar/oaqps/pams/analysis/receptor/rectxtsac.html)and confirmed through our calculations. Finally, inthe raw dataset, sample dates and recorded values for thosedates (depending on the collection frequency) are included.The dataset, entitled DM_AMP450, contains all of the variablesmentioned above; however, instead of multiple readingsper day for all days of collection, an arithmetic mean is reported.In order to obtain this mean, the EPA simply added all monitoredvalues and divided by the total number present. Noreadings are excluded. For verification, arithmetic means werecalculated using the “raw” dataset and confirmed against the“summary” dataset.31
Page 1 and 2: A Closer Look at Air Pollution in H
Page 3 and 4: A Closer Look at Air Pollution in H
Page 5 and 6: Task Force MembersResearch StaffKen
Page 7 and 8: AcknowledgementsThe Task Force woul
Page 10: Just because a task is difficult, h
Page 13 and 14: ing, and route of exposure, and oth
Page 15 and 16: and vulnerable subgroups. Substance
Page 17 and 18: accurately from death certificates.
Page 19 and 20: assessments, and monitoring data fr
Page 21 and 22: The reality is that, even at simila
Page 23 and 24: ability, have inadequate means to c
Page 25 and 26: Houston reaches $21,701. These are
Page 27 and 28: In summary, we view the comparative
Page 29 and 30: AppendicesPhoto by Heidi Bethel27
Page 31: Photo by Heidi Bethelgrouping to a
Page 35 and 36: Appendix 3an appreciable risk of ad
Page 37 and 38: Table A3.1. Health Values and Refer
Page 43 and 44: Appendix 4Metals, Diesel PM Convers
Page 45 and 46: Under advice from staff at the U.S.
Page 47 and 48: Appendix 5Table A5.1. Uncertain Ris
Page 49 and 50: Appendix 6Brief Descriptions of Hea
Page 51 and 52: Appendix 7Summary Map and Table for
Page 53 and 54: Appendix 8: Table 1Supplemental Tab
Page 55 and 56: Appendix 8: Table 3Table A8.3. Poss
Page 57 and 58: ReferencesHackett, P., Sikov, M., &

A Closer Look at Air Pollution in Houston: - Green Houston

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?