Cumulative Cancer Risk from Air Pollution in Houston: Disparities in Risk Burden and Social Disadvantage

Abstract

Air toxics are of particular concern in Greater Houston, home to one of the world’s largest petrochemical complexes and a quarter of the nation’s refining capacity. Much of this complex lies along a navigable ship channel that flows 50 miles from east of the central business district through Galveston Bay and into the Gulf of Mexico. Numerous communities, including both poor and affluent neighborhoods, are located in close proximity to the 200 facilities along this channel. Our aim is to examine the spatial distribution of cumulative, air-pollution-related cancer risks in Houston and Harris County, with particular emphasis on identifying ethnic, economic, and social disparities. We employ exposure estimates from NATA-1999 and census data to assess whether the cumulative cancer risks from air toxics in Houston (and Harris County) fall disproportionately on certain ethnicities and on the socially and economically disadvantaged. The cancer risk burden across Harris County census tracts increases with the proportion of residents who are Hispanic and with key indicators of relative social disadvantage. Aggregate disadvantage grows at each higher level of cancer risk. The highest cancer risk in Harris County is concentrated along a corridor flanking the ship channel. These high-risk neighborhoods, however, vary markedly in relative disadvantage, as well as in emission source mix. Much of the risk they face appears to be driven by only a few hazardous air pollutants. Results provide evidence of risk disparities from hazardous air pollution based on ethnicity and social disadvantage. At the highest levels of risk the pattern is more complex, arguing for a neighborhood level of analysis, especially when proximity to high-emissions industries is a substantial contributor to cumulative cancer risk.

Sources, trends and regional impacts of fine particulate matter in southern Mississippi valley: significance of emissions from sources in the Gulf of Mexico coast

“…It is predicted that in the absence of emission controls, SO 2 emissions to the total emissions in the US would increase from 21 % today to 81 %, NO x emissions would increase to 28 % of total mobile NO x emissions in the US, and PM 2.5 emissions would almost triple to 170 000 tons yr −1 by 2030 (Corbett et al, 2003;Dalsoren et al, 2009;Eyring et al, 2010). Diesel particles from ships and secondary aerosol from the oxidation of NO 2 and SO 2 are shown to be related to 50-500 cancer cases, 750 asthma attacks and 29 premature deaths per million people within 15 miles of the port and influence the air quality in receptor sites far away from the coast (Corbett et al, 2007;Linder et al, 2008).…”

Using exposure biomarkers in children to compare between-child and within-child variance and calculate correlations among siblings for multiple environmental chemicals

“…Despite the scarcity of data, there is mounting presumptive evidence that children residing in low-income, inner-city neighborhoods are likely to experience higher-than-average concurrent exposures to a diversity of environmental chemicals (Sexton, 1997;Faber and Kreig, 2002;MorelloFrosch and Shenassa, 2006;Sexton et al, 2006Sexton et al, , 2011Linder et al, 2008;Sexton and Linder, 2010). Studying children's exposure in these communities is difficult for a plethora of reasons, including mistrust of researchers, frequent address changes, and high crime rates .…”

Emission Scenarios and the Health Risks Posed by Priority Mobile Air Toxics in an Urban to Regional Area: An Application in Nashville, Tennessee

“…The cumulative cancer risk posed by gaseous air toxics (acetaldehyde, benzene, 1,3-butadiene, and formaldehyde) was called 4HAPs, and the cumulative cancer risk for those 4 air toxics and DPM was called 4HAPs + DPM. The IUR values used in NATA are quite different than used in this current study; in fact NATA is starting to use a much lower value for formaldehyde toxicity than in IRIS, and that benzene toxicity is characterized in IRIS with a range (Apelberg et al, 2005;Marshall et al, 2005;Linder et al, 2008;Ozkaynak et al, 2008). As our study compared different scenarios and its contributions on cancer risk, the 2003 IUR values used by IRIS were reasonable.…”

“…Currently, EPA has used a Gaussian plume model (ASPEN) and an exposure model to estimate the annual HAPs concentrations to assess health risk based on the National-Scale Air Toxics Assessment (NATA). This is a state-of-the-science screening tool for State/Local/Tribal Agencies to prioritize pollutants, emission sources and locations of interest for further study in order to gain a better understanding of risks (Linder et al, 2008;Ozkaynak et al, 2008;USEPA, 2012). The model has been performed for local scale effects on ambient concentrations from emitted HAPs that have long atmospheric lifetimes, slow loss rates, without biogenic emissions, and no photochemical production.…”