Search

Spatial variation in childhood asthma and a recent increase in prevalence indicate that environmental factors play a significant role in the etiology of this important disease. Socioeconomic position (SEP) has been associated inversely and positively with childhood asthma. These contradictory results indicate a need for systematic research about SEP and asthma. Pathways have been suggested for effects of SEP on asthma at both the individual and community level. We examined the relationship of prevalent asthma to community-level indicators of SEP among 5762 children in 12 Southern California communities, using a multilevel random effects model. Estimates of community-level SEP were derived by summarizing census block group-level data using a novel method of weighting by the proportion of the block groups included in a community-specific bounding rectangle that contained 95% of local study subjects. Community characteristics included measures of male unemployment, household income, low education (i.e., no high school diploma) and poverty. There was a consistent inverse association between male unemployment and asthma across the inter-quartile range of community unemployment rates, indicating that asthma rates increase as community SEP increases. The results were robust to individual-level confounding, methods for summarizing census block group data to the community level, scale of analysis (i.e., community-level vs. neighborhood-level) and the modeling algorithm. The positive association between SEP and prevalent childhood asthma might be explained by differential access to medical care that remains unmeasured, by the hygiene hypothesis (e.g., lower SES may associate with higher protective exposures to endotoxin in early life), or by SEP acting as a proxy for unmeasured neighborhood characteristics. Keywords: USA; Neighborhood; Childhood asthma; Multilevel modeling; Socioeconomic position; Contextual factor

Abstracts This paper analyses the association between traffic-generated air pollution and neighbourhood socioeconomic status in Toronto. Based on a special sampling campaign of 95 nitrogen dioxide monitors in 2002, ambient [...]

ABSTRACT This paper reports on the development of a land use regression (LUR) model for predicting the intraurban variation of traffic-related air pollution in Hamilton, Ontario, Canada, an industrial city [...]

The National Children's Study is considering a wide spectrum of airborne pollutants that are hypothesized to potentially influence pregnancy outcomes, neurodevelopment, asthma, atopy, immune development, obesity, and pubertal development. In [...]

ABSTRACT The purpose of this study was to derive a land-use regression model to estimate on a geographical basis ambient concentrations of nitrogen dioxide (N[O.sub.2]) in Montreal, Quebec, Canada. These [...]

Environmental exposure research tends to emphasize the monitoring and regulation of emissions, with fewer investigations of exposure experienced in the general population. To help bridge the gap between environmental quality and perceived exposure, this study examines ambient exposures among 300 residents from each of 4 neighborhoods and among a control group of 300 residents in Hamilton, Ontario, Canada. Logistic regression analyses determined how individual, neighborhood, and housing characteristics influenced self-reported exposure in the workplace, inside the home, and around the home. Blue-collar occupations, neighborhood dislikes, and a home in disrepair were associated with work exposure. Neighborhood dislikes, renting, and indicating how the neighborhood could be healthier were associated with indoor exposure. Pesticide exposure was linked to professional occupations and to a specific neighborhood. Older homes were also associated with pesticide and indoor exposure. The findings highlight the need for further research on indoor exposure indices and on perceptions of neighborhood quality. Keywords: environmental quality; exposure; home; workplace; pesticides; Hamilton, Canada

Scientists and policymakers have shown growing interest in the health effects of chronic air pollution exposure. In this study, we use geostatistical techniques in combination with small-area data to address a central research question: 'Does chronic exposure to particulate air pollution significantly associate with mortality when the effects of other social, demographic, and lifestyle confounders are taken into account?' Our analysis relies on age-standardized mortality ratios for census tracts (CTs) of Hamilton (average population of 3419 persons), social and demographic data from the 1991 Census of Canada, smoking variables extracted from secondary surveys, and total suspended particulate (TSP) data from 23 monitoring stations operated by the Ministry of the Environment. Air pollution data are interpolated with a geostatistical procedure known as 'kriging'. This method translates fixed-site pollution monitoring observations into a continuous surface, which was overlaid onto the population-weighted centroids of the CTs. Our results show substantively large and statistically significant health effects for women and men. Evaluated over the interquartile range of the data, we found the relative risk of premature mortality for TSP exposure to be 1.19 (95% CI: 1.13-1.26) for women and 1.30 (95% CI: 1.24-1.37) for men. We also tested associations with cardio-respiratory and cancer mortality. We found positive, significant associations between particulate exposure and these causes of death in most models. Inclusion of socioeconomic, demographic, and lifestyle reduced but did not eliminate the health effects of exposure to particulate air pollution. Overall our results suggest that intra-urban variations in particulate air pollution significantly associate with premature, all-cause, cardio-respiratory, and cancer mortality in small areas of Hamilton. Keywords: Air pollution; Health effects; Lifestyle; Socioeconomic factors; Geostatistics; Canada

Associations have been found between long-term exposure to ambient air pollution and cardiovascular morbidity and mortality. The contribution of air pollution to atherosclerosis that underlies many cardiovascular diseases has not [...]

The effects of both ambient air pollution and socioeconomic position (SEP) on health are well documented. A limited number of recent studies suggest that SEP may itself play a role [...]

This article addresses two questions: (1) How do spatiotemporal changes in air pollution levels--specifically, total suspended particulates (TSP)--rise or fall with socioeconomic status? (2) A critical equity interpretation of environmental policy then motivates this question: does the pursuit of average regional reductions in pollution benefit those who need improvements least, benefit those who need improvements most, or maintain the status quo? TSP data are drawn from networks of monitoring stations operated in 1985, 1990, and 1995. The monitoring data are interpolated with a kriging algorithm to produce estimates of likely pollution distribution throughout Hamilton. Exposure is related to socioeconomic status (SES) variables at the census tract level for corresponding years--1986, 1991, and 1996--and associations are tested with ordinary least squares (OLS) and spatial regression models. The results show that whether TSP rises or falls, injustice persists but becomes less pronounced over time. Among all SES indicators, dwelling value consistently predicts TSP levels for all years, suggestive of a land-rent/ spatial-externalities dynamic. As we move forward in time, it becomes increasingly difficult to differentiate air-pollution exposure among Hamilton neighborhoods, as industrial TSP sources become more dispersed in the region and transportation pollution becomes relatively more important. We conjecture that more equitable distributions of air pollution have resulted more from post-Fordist industrial and spatial restructuring than from environmental policy intervention. Injustice in Hamilton and its apparent relationship with changing industrial structure appear similar to results in the United States and speak to a continental, intraurban environmental-justice experience. Key Words: air pollution, environmental justice, GIS, Hamilton, kriging.

Epidemiologic studies that implement area-based ambient air pollution measures to understand population-level health outcomes primarily use home address to assign exposure values to participants. However, as children spend a considerable amount of time at school, ambient air pollution levels at school locations may also be associated with health outcomes, particularly for pediatric asthma. We evaluated the impact of assigning a location-weighted average of nitrogen dioxide (NO2), a marker of traffic-related air pollution, on self-reported asthma symptoms in an urban cohort of middle school children based on combined school and home locations compared to home and school location alone. Middle school students in Oakland, CA (n = 4017), were administered a survey based on a modified International Study of Asthma and Allergy in Childhood (ISAAC) questionnaire. Annual average NO2 values were assigned to students' home address, school address, and a time-weighted average of the two locations from an annual land use regression model for the county. We implemented logistic regression to compare quartiles of home, school, and location-weighted average NO2 exposure for the eleven symptoms collected in the survey. Based on survey responses, for children classified as "current asthma," significant associations between NO2 exposure and asthma symptoms were found at home locations only. Students in the 2nd quartile of exposure were more likely to report wheezing and trouble sleeping compared to students in the 1st quartile of exposure at home (adjusted odds ratio [OR] = 1.152, 95% CI: 1.042, 2.310, and OR = 1.531, 95% CI: 1.020, 2.296, respectively). School-based exposures maintained lower, non-significant OR with wheezing and trouble sleeping for students in the 2nd quartile of NO2 (OR = 1.125, 95% CI: 0.748, 1.694 and OR = 1.262, 95% CI: 0.832, 1.916, respectively), while location-weighted average OR for both symptoms were attenuated compared to both locations and not statistically significant. Studies that assign area-based pollution measures at home only may not account for total pollution exposures, especially for children who spend a considerable portion of time in school locations. [ABSTRACT FROM AUTHOR]

Municipal amalgamations in Toronto and other regions of Ontario have rekindled a debate over whether larger city-regions supply services at a lower cost per capita than smaller regions. As in [...]

Recent advances in local spatial statistics and operational computing capacity have led to growing interest in the detection of disease clusters for public health surveillance and for improving understanding of [...]

Research indicates that low income, dwelling values and unemployment are significant predictors of particulate air pollution exposure in Hamilton, Ontario, Canada. Findings were obtained through the use of geographic information systems and spatial analysis.