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

Houston reaches $21,701. These are neighborhoods whereresidents live on less than half of the income of their fellowHoustonians.In Harrisburg/Manchester, 37 percent of the residentshave less than a high school education, and 32 percent fallbelow the Federal poverty level - double the rate for the surroundingcounty. In Clinton Park, 27 percent have less than ahigh school education, and the same percent fall below thepoverty level. The residents in these neighborhoods are alsosegregated by race or ethnicity. Clinton Park is over 90 percentAfrican-American. Harrisburg/Manchester is 88 percentHispanic. Further, the pattern of land use shows pockets ofresidences surrounded by industrial sites, either disposallagoons for dredged material from the Ship Channel at ClintonPark or fence lines behind heavy industry for Harrisburg/Manchester. The conditions necessary for healthy lifestyles,economic sustenance and quality of life for residents are fewerhere than in most neighborhoods.Aside from vulnerability, there is also the question ofwhether the sources of the pollutants posing the highest risksare the same in East Houston as in the rest of the GreaterHouston Area. As it turns out, they are typically not the same.For East Houston, NATA attributes the ambient modeled concentrationsof 7 of the top 12 pollutants to point sources; for theGreater Houston Area, this number drops to 3. East Houstonhad no pollutants where area sources dominated among thosein the definite risk category; Greater Houston had 1. Betweenon-road and non-road mobile sources, the most dramatic differenceis for diesel particulate matter: over 90 percent of theambient modeled concentrations in East Houston neighborhoodsare attributed to non-road mobile sources compared tothree-quarters of the total in Greater Houston.The map in Appendix 7 also shows several monitoringsites where one or more of the pollutants in the definite risk categoryare currently being measured (The supplemental TableA8.1 in Appendix 8 shows which pollutants are monitored).Since these sites record ambient concentrations, the levelspresent in any given census tract cannot be accuratelydetermined without considering factors such as wind directionand temperature. Nonetheless, the sites that appear inAppendix 7 recorded annual average concentrations for2004 that exceeded our health value thresholds for posingdefinite health risks. Three of these sites are contained in oradjacent to the neighborhoods that also had the largest numberof definite risk pollutants, based on NATA modeled estimatesfor 1999.In sum, East Houston neighborhoods that face a numberof vulnerabilities based on their marginal social and economicstanding also carry a heavier burden of health risks frombreathing pollutants in their air. They tend to be located closerto major point sources than most other neighborhoods in theGreater Houston area and to be nearer to major transportationcorridors. The burden of these risks taken together poses specialneeds in these neighborhoods.CONCLUSIONS AND RECOMMENDATIONSSubstantial efforts have been devoted over the years toscrutinizing air pollution levels in Houston, and considerableresources have been expended on mitigation measures.Although the success of these endeavors is difficult to quantify,it appears that levels of some air pollutants, like ozone, havedecreased since the early 1980s even though Houston's population,economy, and traffic have grown steadily. Much of theprogress over the past 35 years can be attributed to regulatorycontrols mandated by the 1970 Clean Air Act and subsequentamendments. But air quality improvements in Houston appearto have slowed or even stalled recently, and there is legitimateconcern that matters will only get worse. A critical first step infinding cost-effective solutions is to identify those airborne pollutantsthat represent the most serious health risks so that controlstrategies can be designed to focus on the worst risks first.Historically, federal and state regulatory efforts have beendirected primarily toward meeting National Ambient Air QualityStandards for the 6 criteria pollutants commonly found in urbanair. Most of the attention in Houston has been on ozone -- theonly criteria pollutant for which the city is not in compliance --because of harsh penalties mandated by the Clean Air Act ifambient ozone concentrations do not meet the 8-hour standardby June 2010 (an unlikely prospect). There is also a growingbody of evidence indicating that fine particulate matter causessignificant health effects at ambient concentrations below the23