Effects of land cover and air pollution on the risk of preterm births.

OBJECTIVE: To evaluate the association between gestational age and green areas, urban built areas, and the concentration of particulate matter 2.5 (PM2.5) in the city of São Paulo, analyzing the irregular distribution of these areas and pollution levels above the recommended level. METHODS: The study population consisted of a cohort of live births from 2012, and data from the Live Birth Information System (Sinasc) of the city of São Paulo were used. Using satellite images and supervised classification, the distribution and quantity of green areas and built areas in the city of São Paulo was obtained, as well as the concentrations of PM2.5. Logistic regressions were used to obtain possible associations. RESULTS: The results of the study show that a lower percentage of green areas is significantly associated with a higher chance of preterm births. A higher building density was positively associated with the odds ratio for preterm birth. We did not find any significant associations between air pollution (PM2.5) and preterm births. CONCLUSIONS: The results of this study show that greener areas are less associated with preterm births when compared with less green areas.

Effects of land cover and air pollution on the risk of preterm births / Efeitos da cobertura de solo e poluição do ar no risco de nascimentos prematuros

ABSTRACT OBJECTIVE To evaluate the association between gestational age and green areas, urban built areas, and the concentration of particulate matter 2.5 (PM2.5) in the city of São Paulo, analyzing the irregular distribution of these areas and pollution levels above the recommended level. METHODS The study population consisted of a cohort of live births from 2012, and data from the Live Birth Information System (Sinasc) of the city of São Paulo were used. Using satellite images and supervised classification, the distribution and quantity of green areas and built areas in the city of São Paulo was obtained, as well as the concentrations of PM2.5. Logistic regressions were used to obtain possible associations. RESULTS The results of the study show that a lower percentage of green areas is significantly associated with a higher chance of preterm births. A higher building density was positively associated with the odds ratio for preterm birth. We did not find any significant associations between air pollution (PM2.5) and preterm births. CONCLUSIONS The results of this study show that greener areas are less associated with preterm births when compared with less green areas.

RESUMO OBJETIVO Avaliar a associação entre a idade gestacional e as áreas verdes, áreas construídas urbanas e a concentração de material particulado 2,5 (MP2,5) em São Paulo, analisando a distribuição irregular dessas áreas e os níveis de poluição acima do recomendado. MÉTODOS A população utilizada no estudo foi a dos nascidos vivos no ano de 2012, com os dados do Sistema de Informações sobre Nascidos Vivo (Sinasc) na cidade de São Paulo. Por meio de imagens de satélites e realizando a classificação supervisionada, obtivemos a distribuição e quantidade de áreas verdes e de áreas construídas, na cidade de São Paulo, assim como as concentrações de MP2,5. Regressões logísticas foram utilizadas para obter possíveis associações. RESULTADOS Os resultados do estudo mostram que menor percentual de áreas verdes está associado significativamente com maior chance de prematuridade. Maior densidade de construção foi associada positivamente com a razão de chance de nascimento prematuro. Não encontramos resultados significativos entre a poluição do ar (MP2,5) e prematuridade. CONCLUSÕES Os resultados deste estudo demostraram que áreas mais verdes em relação às áreas menos verdes são menos associadas a nascimentos prematuros.

Assessing the impact of urban environment and green infrastructure on mental health: results from the São Paulo Megacity Mental Health Survey.

BACKGROUND: Different land cover types in cities, including green areas, have impacts on mental health. Few studies, however, have been conducted in megacities in low-/middle-income countries, which have extremely complex urban arrangements. OBJECTIVE: We analyzed land cover using the population database of the São Paulo Megacity Mental Health Survey (n = 4287) and the associations with the diagnosis of depression/anxiety. METHODOLOGY: Automatic classification of the orthophotos of the metropolitan area was performed using the random forest algorithm to provide land cover variables. The association of mental health data with land cover was determined with logistic regression and multilevel regression models. RESULTS: The percentage of different green spaces, mainly grassed areas, within districts was negatively associated with the presence of anxiety (OR 0.994, 0.968, 0.994, respectively), while roofs, asphalt and shadow (OR 1.007, 1.021, 1.085, 1.021, 1.014, respectively) were positively associated with the presence of anxiety. These results were more significant in green areas within the fourth quartile [-0.352 (0.158) and -0.347 (0.155), respectively] and in the roofs in the fourth quartile [0.321 (0.159)]. No significant results were found for depression. SIGNIFICANCE: Our data indicate the need for intensive greenery in spaces with different vegetation compositions in urban environments, especially megacities, to improve the mental health of urban dwellers.

Green Spaces, Land Cover, Street Trees and Hypertension in the Megacity of São Paulo.

Proximity to green spaces has been shown to be beneficial to several cardiovascular outcomes in urban spaces. Few studies, however, have analyzed the relationship between these outcomes and green space or land cover uses in low-medium income megacities, where the consequences of rapid and inordinate urbanization impose several health hazards. This study used a subgroup of the dataset from The Brazilian Longitudinal Study of Adult Health ELSA-BRASIL (n= 3418) to identify the correlation between the medical diagnosis of hypertension and green spaces in the megacity of São Paulo. Land cover classification was performed based on the random forest algorithm using geometrically corrected aerial photography (orthophoto). Three different indicators of exposure to green spaces were used: number of street trees, land cover and number of parks within 1 km. We used logistic regression models to obtain the association of the metrics exposure and health outcomes. The number of street trees in the regional governments (OR = 0.937 and number of parks within 1 km (OR = 0.876) were inversely associated with a diagnosis of hypertension. Sixty-three percent of the population had no parks within 1 km of their residence. Our data indicate the need to encourage large-scale street tree planting and increase the number of qualified parks in megacities.

Effectiveness of traffic-related elements in tree bark and pollen abortion rates for assessing air pollution exposure on respiratory mortality rates.

The majority of epidemiological studies correlate the cardiorespiratory effects of air pollution exposure by considering the concentrations of pollutants measured from conventional monitoring networks. The conventional air quality monitoring methods are expensive, and their data are insufficient for providing good spatial resolution. We hypothesized that bioassays using plants could effectively determine pollutant gradients, thus helping to assess the risks associated with air pollution exposure. The study regions were determined from different prevalent respiratory death distributions in the Sao Paulo municipality. Samples of tree flower buds were collected from twelve sites in four regional districts. The genotoxic effects caused by air pollution were tested through a pollen abortion bioassay. Elements derived from vehicular traffic that accumulated in tree barks were determined using energy-dispersive X-ray fluorescence spectrometry (EDXRF). Mortality data were collected from the mortality information program of Sao Paulo City. Principal component analysis (PCA) was applied to the concentrations of elements accumulated in tree barks. Pearson correlation and exponential regression were performed considering the elements, pollen abortion rates and mortality data. PCA identified five factors, of which four represented elements related to vehicular traffic. The elements Al, S, Fe, Mn, Cu, and Zn showed a strong correlation with mortality rates (R2>0.87) and pollen abortion rates (R2>0.82). These results demonstrate that tree barks and pollen abortion rates allow for correlations between vehicular traffic emissions and associated outcomes such as genotoxic effects and mortality data.

An oblique effect in parafoveal motion perception.

An observer's ability to discriminate the angular direction of a moving grating depends on the grating orientation. Observers can more accurately judge the angular direction of vertical or horizontal gratings than oblique gratings. We discovered that this oblique effect becomes very large at high spatial frequencies in the parafovea. Perceived direction was quantified with a direction matching task at spatial frequencies ranging from 7.6 to 22.6 c/deg. As spatial frequency increased, direction matches of oblique gratings deviated away from the diagonal and towards vertical or horizontal axes. Subjects reported that the higher spatial frequency gratings appeared as grainy noise, particularly at oblique orientations. Our results indicate that, in the parafovea, subjects perceive movement of high spatial frequencies mainly along principal meridians. One possible explanation for this effect is that the high frequency patterns are aliased by the irregular mosaic of parafoveal cones. The aliasing noise generated by irregular sampling contains spatial energy at all orientations, but perhaps only vertical and horizontal components of the noise are visible to the observer.

Consequences of spatial sampling for human motion perception.

This paper describes evidence for spatial aliasing in human motion perception. For a certain range of spatial frequencies, interference fringes drifting across the extrafoveal retina resemble two-dimensional spatial noise drifting in the opposite direction. For retinal locations within 10 deg of the fovea, the perceived direction of motion is veridical up to spatial frequencies near the cone Nyquist frequency, reverses between one and two times the cone Nyquist frequency, and sometimes reverses back to the correct direction at still higher frequencies. Thus two "motion nulls", or spatial frequencies at which the direction of motion is ambiguous, are typically observed at each retinal eccentricity. A computational model is described in which sinusoidal gratings are sampled by a cone mosaic and the direction of motion of the filtered output is computed. The model predicts that the second motion null, but not the first, should be relatively immune to postreceptoral processing and should roughly equal twice the cone Nyquist frequency. This prediction is confirmed by psychophysical experiments, providing a new technique to estimate cone spacing in the living human eye.