Research Hub

Background
Although studies suggest that exposure to pollutants is associated with race/ethnicity and socio-economic status (SES), many studies are limited to the geographic regions where monitoring stations are located.

Results
SES and race/ethnicity were related to predicted concentrations of both PM2.5 and O3 for census tracts in North Carolina. Lower SES and higher proportion minority population were associated with higher levels of PM2.5. An interquartile range (IQR) increase of median household income reduced the predicted average PM2.5 level by 0.10 µg/m3. The opposite relationship was true for O3. An IQR increase of median household income increased the predicted average O3 measure by 0.11 ppb.

Conclusions
The analyses demonstrate that SES and race/ethnicity are related to predicted estimates of PM2.5 and O3 for census tracts in North Carolina. These findings offer a baseline for future exposure modeling work involving SES and air pollution for the entire state and not just among the populations residing near monitoring networks.

Published Oct 1, 2013

Gray, S. C., Edwards, S. E., & Miranda, M. L. (2013). Race, socioeconomic status, and air pollution exposure in North Carolina. Environmental Research, 126, 152–158. https://doi.org/10.1016/j.envres.2013.06.005

Climate change is a health threat no less consequential than cigarette smoking. Increased concentrations of greenhouse gases, and especially CO 2, in the earth's atmosphere have already warmed the planet substantially, causing more severe and prolonged heat waves, temperature variability, air pollution, forest fires, droughts, and floods, all of which put respiratory health at risk. These changes in climate and air quality substantially increase respiratory morbidity and mortality for patients with common chronic lung diseases such as asthma and COPD and other serious lung diseases. Physicians have a vital role in addressing climate change, just as they did with tobacco, by communicating how climate change is a serious, but remediable, hazard to their patients. © 2013 American College of Chest Physicians.

Published May 1, 2013

Bernstein, A. S., & Rice, M. B. (2013). Lungs in a warming world: Climate change and respiratory health. Chest, 143(5), 1455–1459. https://doi.org/10.1378/chest.12-2384

Although many time-series studies of ozone and mortality have identified positive associations, others have yielded null or inconclusive results, making the results of these studies difficult to interpret. METHODS We performed a meta-analysis of 144 effect estimates from 39 time-series studies, and estimated pooled effects by lags, age groups, cause-specific mortality, and concentration metrics. We compared results with pooled estimates from the National Morbidity, Mortality, and Air Pollution Study (NMMAPS), a time-series study of 95 large U.S. urban centers from 1987 to 2000. RESULTS Both meta-analysis and NMMAPS results provided strong evidence of a short-term association between ozone and mortality, with larger effects for cardiovascular and respiratory mortality, the elderly, and current-day ozone exposure. In both analyses, results were insensitive to adjustment for particulate matter and model specifications. In the meta-analysis, a 10-ppb increase in daily ozone at single-day or 2-day average of lags 0, 1, or 2 days was associated with an 0.87% increase in total mortality (95% posterior interval = 0.55% to 1.18%), whereas the lag 0 NMMAPS estimate is 0.25% (0.12% to 0.39%). Several findings indicate possible publication bias: meta-analysis results were consistently larger than those from NMMAPS; meta-analysis pooled estimates at lags 0 or 1 were larger when only a single lag was reported than when estimates for multiple lags were reported; and heterogeneity of city-specific estimates in the meta-analysis were larger than with NMMAPS. CONCLUSIONS This study provides evidence of short-term associations between ozone and mortality as well as evidence of publication bias.

Published Feb 25, 2013

Bell, M. L., Dominici, F., & Samet, J. M. (2005). A meta-analysis of time-series studies of ozone and mortality with comparison to the national morbidity, mortality, and air pollution study. Epidemiology (Cambridge, Mass.), 16(4), 436–445. https://doi.org/10.1097/01.ede.0000165817.40152.85

Childhood cognitive and test-taking abilities have long-term implications for educational achievement and health, and may be influenced by household environmental exposures and neighborhood contexts. This study evaluates whether age 5 scores on the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R, administered in English) are associated with polycyclic aromatic hydrocarbon (PAH) exposure and neighborhood context variables including poverty, low educational attainment, low English language proficiency, and inadequate plumbing. The Columbia Center for Children's Environmental Health enrolled African-American and Dominican-American New York City women during pregnancy, and conducted follow-up for subsequent childhood health outcomes including cognitive test scores. Individual outcomes were linked to data characterizing 1-km network buffers around prenatal addresses, home observations, interviews, and prenatal PAH exposure data from personal air monitors. Prenatal PAH exposure above the median predicted 3.5 point lower total WPPSI-R scores and 3.9 point lower verbal scores; the association was similar in magnitude across models with adjustments for neighborhood characteristics. Neighborhood-level low English proficiency was independently associated with 2.3 point lower mean total WPPSI-R score, 1.2 point lower verbal score, and 2.7 point lower performance score per standard deviation. Low neighborhood-level educational attainment was also associated with 2.0 point lower performance scores. In models examining effect modification, neighborhood associations were similar or diminished among the high PAH exposure group, as compared with the low PAH exposure group. Early life exposure to personal PAH exposure or selected neighborhood-level social contexts may predict lower cognitive test scores. However, these results may reflect limited geographic exposure variation and limited generalizability. © 2013 Springer Science+Business Media New York.

Published Feb 20, 2013

Lovasi, G. S., Eldred-Skemp, N., Quinn, J. W., Chang, H. wen, Rauh, V. A., Rundle, A., Orjuela, M. A., & Perera, F. P. (2014). Neighborhood Social Context and Individual Polycyclic Aromatic Hydrocarbon Exposures Associated with Child Cognitive Test Scores. Journal of Child and Family Studies, 23(5), 785–799. https://doi.org/10.1007/s10826-013-9731-4

In recent years, several studies show that people who live, work or attend school near the main roadways have an increased incidence and severity of health problems that may be related with traffic emissions of air pollutants. The concentrations of near-road atmospheric pollutants vary depending on traffic patterns, environmental conditions, topography and the presence of roadside structures. In this study, the vertical and horizontal variation of nitrogen dioxide (NO2) and benzene (C6H6) concentration along a major city ring motorway were analysed. The main goal of this study is to try to establish a distance from this urban motorway considered " safe" concerning the air pollutants human heath limit values and to study the influence of the different forcing factors of the near road air pollutants transport and dispersion. Statistic significant differences (p=0.001, Kruskal-Wallis test) were observed between sub-domains for NO2 representing different conditions of traffic emission and pollutants dispersion, but not for C6H6 (p=0.335). Results also suggest significant lower concentrations recorded at 100m away from roadway than at the roadside for all campaigns (p<0.016 (NO2) and p<0.036 (C6H6), Mann-Whitney test). In order to have a " safe" life in homes located near motorways, the outdoor concentrations of NO2 must not exceed 44-60.0μgm3 and C6H6 must not exceed 1.4-3.3μgm3. However, at 100m away from roadway, 81.8% of NO2 receptors exceed the annual limit value of human health protection (40μgm3) and at the roadside this value goes up to 95.5%. These findings suggest that the safe distance to an urban motorway roadside should be more at least 100m. This distance should be further studied before being used as a reference to develop articulated urban mobility and planning policies. © 2013 Elsevier Ltd.

Published Jan 21, 2013

Barros, N., Fontes, T., Silva, M. P., & Manso, M. C. (2013). How wide should be the adjacent area to an urban motorway to prevent potential health impacts from traffic emissions? Transportation Research Part A: Policy and Practice, 50, 113–128. https://doi.org/10.1016/j.tra.2013.01.021

As a replication and extension of two previous studies [Pastor, M. Jr., Sadd, J., and Morello-Frosch, R., 2004. Reading, writing and toxics: children's health, academic performance, and environmental justice in Los Angeles. Environment and Planning C: Government and Policy, 22 (2), 271-290, Lucier, C., et al., 2011. Toxic pollution and school performance scores: environmental ascription in East Baton Rouge Parish, Louisiana. Organization & Environment, 24 (4), 421-441], the current study seeks to expand on the growing literature linking environmental inequality and disparities in educational outcomes among vulnerable populations by identifying the environmental determinants of variation in school performance in Worcester County, Massachusetts. Our findings show that schools rating lower in school performance were more likely to be located in more polluted areas, and that these schools had higher percentages of low-income and minority students. Our newly introduced, more targeted measure of toxicity is significant in all three equations in the present study. It is important to note that these significant impacts are found in a county that has much lower levels of overall pollution than in the sites studied previously. That is, the effect of toxins is significant even where pollution levels are modest. © 2013 © 2013 Taylor & Francis.

Published Dec 28, 2012

Rosofsky, A., Lucier, C. A., London, B., Scharber, H., Borges-Mendez, R., & Shandra, J. (2014). Environmental ascription in Worcester County, MA: toxic pollution and education outcomes. Local Environment, 19(3), 283–299. https://doi.org/10.1080/13549839.2013.788485

This study examines race- and income-based disparities in cancer risks from air toxics in Cancer Alley, LA, USA. Risk estimates were obtained from the 2005 National Air Toxics Assessment and socioeconomic and race data from the 2005 American Community Survey, both at the census tract level. Disparities were assessed using spatially weighted ordinary least squares (OLS) regression and quantile regression (QR) for five major air toxics, each with cancer risk greater than 10−6. Spatial OLS results showed that disparities in cancer risks were significant: People in low-income tracts bore a cumulative risk 12% more than those in high-income tracts (p < 0.05), and those in black-dominant areas 16% more than in white-dominant areas (p < 0.01). Formaldehyde and benzene were the two largest contributors to the disparities. Contributions from emission sources to disparities varied by compound. Spatial QR analyses showed that magnitude of disparity became larger at the high end of exposure range, indicating worsened disparity in the poorest and most highly concentrated black areas. Cancer risk of air toxics not only disproportionately affects socioeconomically disadvantaged and racial minority communities, but there is a gradient effect within these groups with poorer and higher minority concentrated segments being more affected than their counterparts. Risk reduction strategies should target emission sources, risk driver chemicals, and especially the disadvantaged neighborhoods.

Published Dec 3, 2012

James W, Jia C, Kedia S. Uneven Magnitude of Disparities in Cancer Risks from Air Toxics. International Journal of Environmental Research and Public Health. 2012; 9(12):4365-4385. https://doi.org/10.3390/ijerph9124365

Most of currently reported models for predicting PM2.5 concentrations from satellite retrievals of aerosol optical depth are global methods without considering local variations, which might introduce significant biases into prediction results. In this paper, a geographically weighted regression model was developed to examine the relationship among PM2.5, aerosol optical depth, meteorological parameters, and land use information. Additionally, two meteorological datasets, North American Regional Reanalysis and North American Land Data Assimilation System, were fitted into the model separately to compare their performances. The study area is centered at the Atlanta Metro area, and data were collected from various sources for the year 2003. The results showed that the mean local R2 of the models using North American Regional Reanalysis was 0.60 and those using North American Land Data Assimilation System reached 0.61. The root mean squared prediction error showed that the prediction accuracy was 82.7% and 83.0% for North American Regional Reanalysis and North American Land Data Assimilation System in model fitting, respectively, and 69.7% and 72.1% in cross validation. The results indicated that geographically weighted regression combined with aerosol optical depth, meteorological parameters, and land use information as the predictor variables could generate a better fit and achieve high accuracy in PM2.5 exposure estimation, and North American Land Data Assimilation System could be used as an alternative of North American Regional Reanalysis to provide some of the meteorological fields. © 2012 Elsevier Inc.

Published Nov 3, 2012

Hu, X., Waller, L. A., Al-Hamdan, M. Z., Crosson, W. L., Estes, M. G., Estes, S. M., Quattrochi, D. A., Sarnat, J. A., & Liu, Y. (2013). Estimating ground-level PM2.5 concentrations in the southeastern U.S. using geographically weighted regression. Environmental Research, 121, 1–10. https://doi.org/10.1016/j.envres.2012.11.003

Background
Adverse birth outcomes such as low birth weight and premature birth have been previously linked with exposure to ambient air pollution. Most studies relied on a limited number of monitors in the region of interest, which can introduce exposure error or restrict the analysis to persons living near a monitor, which reduces sample size and generalizability and may create selection bias.

Methods
We evaluated the relationship between premature birth and birth weight with exposure to ambient particulate matter (PM2.5) levels during pregnancy in Massachusetts for a 9-year period (2000–2008). Building on a novel method we developed for predicting daily PM2.5 at the spatial resolution of a 10x10km grid across New-England, we estimated the average exposure during 30 and 90 days prior to birth as well as the full pregnancy period for each mother. We used linear and logistic mixed models to estimate the association between PM2.5 exposure and birth weight (among full term births) and PM2.5 exposure and preterm birth adjusting for infant sex, maternal age, maternal race, mean income, maternal education level, prenatal care, gestational age, maternal smoking, percent of open space near mothers residence, average traffic density and mothers health.

Results
Birth weight was negatively associated with PM2.5 across all tested periods. For example, a 10 μg/m3 increase of PM2.5 exposure during the entire pregnancy was significantly associated with a decrease of 13.80 g [95% confidence interval (CI) = −21.10, -6.05] in birth weight after controlling for other factors, including traffic exposure. The odds ratio for a premature birth was 1.06 (95% confidence interval (CI) = 1.01–1.13) for each 10 μg/m3 increase of PM2.5 exposure during the entire pregnancy period.

Conclusions
The presented study suggests that exposure to PM2.5 during the last month of pregnancy contributes to risks for lower birth weight and preterm birth in infants.

Published Jun 18, 2012

Kloog, I., Melly, S.J., Ridgway, W.L. et al. Using new satellite based exposure methods to study the association between pregnancy pm2.5 exposure, premature birth and birth weight in Massachusetts. Environ Health 11, 40 (2012). https://doi.org/10.1186/1476-069X-11-40

Take a look at a map of the 14-county metro Atlanta region.
Now place a pin on the map to represent the location of
every polluting factory, toxic release, sewage overflow,
and all other points where pollution may originate. When
you finish, you will see thousands of pins on the map. You
will also begin to see some clear patterns: pollution points
are generally found in higher numbers in populous areas,
close to railways, and in industrial centers. Now, overlay
demographic characteristics, including race and income,
onto the map and you will see which populations are living
closest to these pollution points. With some study, you
will see that populations of minorities and the poor are
living in closer proximity to pollution points than are other
populations. So too are those who are not fluent in English.

Published Mar 1, 2012

Thompson, D. D. J. (2012). A Report on Demographics and Pollution in Metro Atlanta. www.GreenLaw.org