Under one canopy? Assessing the distributional environmental justice implications of street tree benefits in Barcelona.

Street trees are an important component of green infrastructure in cities, providing multiple ecosystem services (ES) and hence contributing to urban resilience, sustainability and livability. Still, access to these benefits may display an uneven distribution across the urban fabric, potentially leading to socio-environmental inequalities. Some studies have analyzed the distributional justice implications of street tree spatial patterns, but generally without quantifying the associated ES provision. This research estimated the amount of air purification, runoff mitigation and temperature regulation provided by circa 200,000 street trees in Barcelona, Spain, using the i-Tree Eco tool. Results were aggregated at neighborhood (n = 73) and census tract (n = 1068) levels to detect associations with the distribution of five demographic variables indicating social vulnerability, namely: income, residents from the Global South, residents with low educational attainment, elderly residents, and children. Associations were evaluated using bivariate, multivariate and cluster analyses, including a spatial autoregressive model. Unlike previous studies, we found no evidence of a significant and positive association between the distribution of low income or Global South residents and a lower amount of street tree benefits in Barcelona. Rather, higher ES provision by street trees was associated with certain types of vulnerable populations, especially elderly citizens. Our results also suggest that street trees can play an important redistributive role in relation to the local provision of regulating ES due to the generally uneven and patchy distribution of other urban green infrastructure components such as urban forests, parks or gardens in compact cities such as Barcelona. In the light of these findings, we contend that just green infrastructure planning should carefully consider the distributive implications associated with street tree benefits.

Green gentrification in European and North American cities.

Although urban greening is universally recognized as an essential part of sustainable and climate-responsive cities, a growing literature on green gentrification argues that new green infrastructure, and greenspace in particular, can contribute to gentrification, thus creating social and racial inequalities in access to the benefits of greenspace and further environmental and climate injustice. In response to limited quantitative evidence documenting the temporal relationship between new greenspaces and gentrification across entire cities, let alone across various international contexts, we employ a spatially weighted Bayesian model to test the green gentrification hypothesis across 28 cities in 9 countries in North America and Europe. Here we show a strong positive and relevant relationship for at least one decade between greening in the 1990s-2000s and gentrification that occurred between 2000-2016 in 17 of the 28 cities. Our results also determine whether greening plays a "lead", "integrated", or "subsidiary" role in explaining gentrification.

Adapting the environmental risk transition theory for urban health inequities: An observational study examining complex environmental riskscapes in seven neighborhoods in Global North cities.

Theories of epidemiologic transition analyze the shift in causes of mortality due to changes in risk factors over time, and through processes of urbanization and development by comparing risk factors between countries or over time. These theories do not account for health inequities such as those resulting from environmental injustice, in which minority and lower income residents are more likely to be exposed to environmental hazards or have less access to environmental goods. Neighborhoods with histories of environmental injustice are also at risk for gentrification as they undergo environmental improvements and new greening projects. We aimed to understand how environmental injustice, urban renewal and green gentrification could inform the understanding of epidemiologic risk transitions. We examined 7 case neighborhoods in cities in the United States and Western Europe which were representative in terms of city region and type, which 1) had experienced a history of environmental injustice and 2) exhibited evidence of recent processes of urban renewal and/or gentrification. In each city, we conducted semi-structured qualitative interviews (n = 172) with city representatives, activists, non-profits, developers and residents. Respondents reported health implications of traditional (heavy pollutants, poor social conditions), transitional (decontamination, new amenities), new (gentrification, access to amenities), and emerging (displacement, climate-related risks, re-emergence of traditional exposures) exposures. Respondents reported renewed, complexified and overlapping exposures leading to poor mental and physical health and to new patterns of health inequity. Our findings point to the need for theories of environmental and epidemiologic risk transitions to incorporate analysis of trends 1) on a city-scale, acknowledging that segregation and patterns of environmental injustice have created unequal conditions within cities and 2) over a shorter and more recent time period, taking into account worsening patterns of social inequity in cities.

Mental Health Outcomes in Barcelona: The Interplay between Gentrification and Greenspace.

Greenspace is widely related to mental health benefits, but this relationship may vary by social group. Gentrification, as linked to processes of unequal urban development and conflict, potentially impacts health outcomes. This study explores the relationships between greenspace and mental health and between gentrification and mental health associations. It also further examines gentrification as an effect modifier in the greenspace-mental health association and SES as an effect modifier in the gentrification-mental health association. We used cross-sectional Barcelona (Spain) data from 2006, which included perceived mental health status and self-reported depression/anxiety from the Barcelona Health Survey. Greenspace exposure was measured as residential access to (1) all greenspace, (2) greenways and (3) parks in 2006. Census-tract level gentrification was measured using an index including changes in sociodemographic indicators between 1991 and 2006. Logistic regression models revealed that only greenways were associated with better mental health outcomes, with no significant relationship between mental health and parks or all greenspace. Living in gentrifying neighborhoods was protective for depression/anxiety compared to living in non-gentrifying neighborhoods. However, only residents of gentrifiable census tracts benefited from the exposure to greenways. SES was not found to be an effect modifier in the association between gentrification and mental health. Future research should tackle this study's limitations by incorporating a direct measure of displacement in the gentrification status indicator, accounting for qualitative aspects of greenspace and user's perceptions. Gentrification may undermine the health benefits provided by greenspace interventions.

Natural outdoor environments' health effects in gentrifying neighborhoods: Disruptive green landscapes for underprivileged neighborhood residents.

BACKGROUND: Cities are restoring existing natural outdoor environments (NOE) or creating new ones to address diverse socio-environmental and health challenges. The idea that NOE provide health benefits is supported by the therapeutic landscapes concept. However, several scholars suggest that NOE interventions may not equitably serve all urban residents and may be affected by processes such as gentrification. Applying the therapeutic landscapes concept, this study assesses the impacts of gentrification processes on the associations between NOE and the health of underprivileged, often long-term, neighborhood residents. METHODS: We examined five neighborhoods in five cities in Canada, the United States and Western Europe. Our case studies were neighborhoods experiencing gentrification processes and NOE interventions. In each city, we conducted semi-structured qualitative interviews on NOE interventions, equity/justice, gentrification and health (n = 117) with case study neighborhood residents, community-based organizations, neighborhood resident leaders and other stakeholders such as public agencies staff. RESULTS: Respondents highlighted a variety of interconnected and overlapping factors: the insufficient benefits of NOE to counterbalance other factors detrimental to health, the use of NOE for city branding and housing marketing despite pollution, unwelcomeness, increase of conflicts, threats to physical displacement for themselves and their social networks, unattractiveness, deficient routes, inadequate NOE maintenance and lack of safety in NOE. CONCLUSIONS: Our study demonstrated that underprivileged neighborhood residents were perceived to experience new or improved NOE as what we call "disruptive green landscapes" (i.e. non-therapeutic landscapes with which they were not physically or emotionally engaged) instead of as therapeutic landscapes.

Determining the health benefits of green space: Does gentrification matter?

Urban green space is demonstrated to benefit human health. We evaluated whether neighborhood gentrification status matters when considering the health benefits of green space, and whether the benefits are received equitably across racial and socioeconomic groups. Greater exposure to active green space was significantly associated with lower odds of reporting fair or poor health, but only for those living in gentrifying neighborhoods. In gentrifying neighborhoods, only those with high education or high incomes benefited from neighborhood active green space. Structural interventions, such as new green space, should be planned and evaluated within the context of urban social inequity and change.

Are green cities healthy and equitable? Unpacking the relationship between health, green space and gentrification.

While access and exposure to green spaces has been shown to be beneficial for the health of urban residents, interventions focused on augmenting such access may also catalyse gentrification processes, also known as green gentrification. Drawing from the fields of public health, urban planning and environmental justice, we argue that public health and epidemiology researchers should rely on a more dynamic model of community that accounts for the potential unintended social consequences of upstream health interventions. In our example of green gentrification, the health benefits of greening can only be fully understood relative to the social and political environments in which inequities persist. We point to two key questions regarding the health benefits of newly added green space: Who benefits in the short and long term from greening interventions in lower income or minority neighbourhoods undergoing processes of revitalisation? And, can green cities be both healthy and just? We propose the Green Gentrification and Health Equity model which provides a framework for understanding and testing whether gentrification associated with green space may modify the effect of exposure to green space on health.

Methylated DNA adducts in the large intestine of ICR/Ha and C57BL/Ha mice given 1,2-dimethylhydrazine.

The site-specific incidence of 1,2-dimethylhydrazine (DMH)-induced neoplastic changes in intestinal segments of ICR/Ha mice correlates with the persistence of O6-methylguanine (O6MGua) after a single carcinogen injection. Six hours after the injection, the amount of O6MGua in four anatomic (proximal to distal) segments was 16.0, 20.8, 37.5, and 52.8 mumol/mol guanine, respectively. Correlation between the incidence of neoplasms and the amount of alkylation was also observed 14, 40, and 96 hours after DMH treatment. Similar levels of O6MGua were found in the corresponding colon segments of C57BL/Ha mice. After repeated treatment (5 wk) with unlabeled DMH, the amount of O6MGua still correlated with the incidence of neoplasms in ICR/Ha mice. However, in each strain the level of O6MGua was significantly lower in pretreated mice than in mice without DMH pretreatment. Furthermore, the amount of adducts in DNA isolated from different crypt depths showed that within a few hours of the DMH injection the amount of adducts was independent of DNA synthetic activity. Although ICR/Ha and C57BL/Ha mice have different susceptibility to DMH-induced colon cancer, this interstrain difference is not reflected in the amounts or persistence of the miscoding base O6MGua.

Comparative study of the morphologic, histochemical, and proliferative changes induced in the large intestine of ICR/Ha and C57BL/Ha mice by 1,2-dimethylhydrazine.

The mouse model of 1,2-dimethylhydrazine (DMH)-induced colorectal carcinogenesis was studied to determine the susceptibility of different anatomic segments of the large intestine in ICR/Ha (susceptible) and C57BL/Ha (resistant) mice. In ICR/Ha mice numerous exophytic macroscopic neoplasms were found in the distal colon and rectum after 15 weekly injections of DMH (20 mg/kg). The proximal colon was free of any microscopic or macroscopic neoplasms. In contrast, C57BL/Ha mice given the same treatment showed no macroscopic neoplasms. However, foci of dysplastic crypts were observed throughout the large intestine of C57BL/Ha mice with highest incidence in the distal colon and rectum. In some areas dysplastic crypts were clearly invading the muscularis mucosae and were, therefore, microscopic carcinomas (microcarcinomas). Thus C57BL/Ha mice were not totally resistant to the neoplastic stimulus of DMH, and the susceptibility of the large intestine is site-specific in both mouse strains.

Carcinogens in spacecraft air.

The health effects of long-term exposure to ionizing radiation during spaceflight are a major concern to NASA, especially for missions beyond low-Earth orbit. Experiments involving astronauts will be conducted during the next few years to improve the risk assessment for exposures to ionizing radiation during flights; however, concomitant exposure to certain airborne chemical carcinogens during these experiments could confound the results of radiation experiments. Carcinogens can reach the spacecraft atmosphere from leaking thrusters, from off-gassing materials, from chemical experiments and from human metabolism. The Johnson Space Center Toxicology Group routinely analyzes atmospheric samples collected aboard spacecraft. The exposure limits for radiomimetic compounds such as benzene are reduced because of the potential interaction between radiation and chemical exposures. Analysis of recent spacecraft air samples indicates that the following carcinogens are often present in measurable concentrations: acetaldehyde, dichloromethane, formaldehyde and isoprene. Occasionally, the carcinogens 1,2-dichloroethane, acrolein, benzene and furan are found in atmospheric samples. During normal operating conditions, the low concentrations of and limited periods of exposure to airborne carcinogens are thought to pose minimal health risks to crew members, and should not confound experiments involving sensitive methods to detect biological effects of ionizing radiation.

Inhibition of polygalacturonase from Verticillium dahliae by a polygalacturonase inhibiting protein from cotton.

An extracellular endo-polygalacturonase (PGase) [E.C. 3.2.1.15] was isolated from 18-day-old culture filtrates of Verticillium dahliae and partially purified using gel permeation chromatography. The band responsible for PGase activity was electrophoretically characterized as having a molecular mass of approximately 29 500 and an isoelectric point of 5.4. Kinetic studies indicate a Km of 3.3 mg ml(-1) and Vmax of 0.85 micromol reducing units min(-1) ml(-1) with polygalacturonic acid as substrate. Polygalacturonase inhibitor protein (PGIP) in cotton seedlings was induced by 5 mM salicylic acid and immunochemical analysis indicated high levels in the hypocotyl tissues. PGIP was purified from roots and stems using affinity chromatography with endo-PGase from Aspergillus niger as an immobilised ligand. The purified PGIP contained monomeric and dimeric molecules with molecular masses of 34 and 66 kDa respectively. Purified cotton PGIP inhibited endo-polygalacturonase from A. niger in a non-competitive or mixed manner with an inhibition constant. K(I) of 15 nM. The isolated V. dahliae PGase was, however, inhibited in a positive cooperative manner, indicative of allosteric interactions between the enzyme and the inhibitor protein. In addition to reducing the reaction rate, decreased substrate affinity may contribute to the accumulation of elicitor-active oligouronides.

Clinical chemistry reference values in two breeds of swine and their changes during percutaneous exposure to soman.

Clinical chemistry reference values in blood from 48 nonfasting Chester White/Yorkshire and 48 Hanford Miniature swine were determined. Subsequently, 40 animals of each breed were restrained in a cloth sling and fasted for 24 hours while exposed percutaneously to pinacolyl methylphosphonofluoridate (soman). The range of dosages for the Hanford Miniature swine was 2.0 to 15.8 mg/kg, and for the Chester White/Yorkshire swine, the range was 4.0 to 25.0 mg/kg. Sham-exposed groups, consisting of 8 animals of each breed, were treated in an identical manner, except no anticholinesterase agent was administered. Samples of blood were drawn at 1, 7, 14, and 28 days after soman or sham exposure. In the sham-exposed groups, significant changes from the reference values were observed as a result of the 24-hour restraint. In both breeds, skeletal muscle enzyme activities were increased, plasma cholinesterase activity (ChEPL) was decreased, calcium concentration was decreased, and phosphorus concentration was increased. Percutaneous exposure to soman resulted in decreases of ChEPL and erythrocyte cholinesterase activities (ChERBC). The ChEPL recovered more quickly than the ChERBC in both breeds. Even in asymptomatic swine, the decrease of ChERBC was greater than 60% after 24 hours. In the swine of each breed given the largest dosage, hyperglycemia was apparent in blood samples taken at the onset of apnea, especially when the animal survived for greater than 2 hours. We conclude that both breeds of swine, on the basis of dispersion in clinical chemistry reference values, were equally suited for this type of dermatotoxicity study. The sling method of restraint, however, caused some undesirable changes in biochemical values.

Volatile organic contaminants found in the habitable environment of the Space Shuttle: STS-26 to STS-55.

The health and performance of spacecraft crews can be adversely affected by contaminants present in the respirable air. Contaminants originate from hardware offgassing, crew and microbial metabolism, use of utility chemicals, leakage from fluid systems and payload experiments, and from electrical overheating. The quality of Shuttle air is measured by collecting contaminants in evacuated cylinders or on sorbent resin for later ground-based analysis by gas chromatography (GC) and GC mass spectrometry (MS). The results of those analyses are presented for 28 missions, including 5 Spacelabs which were flown in the payload bay of the Shuttle. The major contaminants were relatively nontoxic alcohols (ethanol, isopropanol), ketones (acetone, diacetone alcohol), alkanes, halocarbons (Halon 1301, Freon 113), and siloxanes. Occasionally, more toxic contaminants, such as methanol, acetaldehyde, and tetrachloroethene, were present at low concentrations (below 1 mg/m3). The contaminant concentrations measured in spacecraft air were compared to spacecraft maximum allowable concentrations (SMAC's) which are set to protect the crew from adverse health effects or performance decrements. Aggregate toxicity assessments (T values) of the contaminants present during each mission, calculated by summing the ratios of measured concentrations to each contaminant's SMAC, showed that air quality consistent met the criterion that the T value be less than 1.

Air quality assessments for two recent Space Shuttle flights.

Degradation of air quality in the Space Shuttle environment through chemical contamination and high solid-particulate levels may affect crew performance and health. A comprehensive study of the Shuttle atmosphere was undertaken during the STS-40 (Spacelab Space Life Sciences 1) and STS-42 (Spacelab International Microgravity Laboratory 1) missions to determine the effectiveness of contaminant control procedures by measuring concentrations of volatile organic compounds and analyzing particulate matter trapped on air filters. Analysis of volatile contaminants showed that the air was toxicologically safe to breathe during both missions with the exception of one period during STS-40 when the Orbiter Refrigerator/Freezer was releasing noxious gases into the middeck. Chemical analyses of selected particles collected on air filters facilitated their positive identification. Trace amounts of rat hair and food particles were found in the STS-40 Spacelab filters; a trace amount of soilless plant-growth media was detected in the STS-42 Spacelab filter. The low levels of particles released from these Spacelab experiments indicate that containment measures were effective.

A breath sampling device for measuring human exposure to volatile organic compounds in microgravity.

A compact device for the collection of alveolar air (breath) from humans aboard spacecraft was developed. The system uses silicone one-way valves that operate independent of gravity, and provide minimal backpressure. Small charcoal filters clean ambient air used for inhalation. The device provided good recoveries of organic compounds at the 20 ng/L level, with generally low carryover of these compounds to a blank sample following a sample at exposure to 100 ng/L. When water accumulated in the system, this carryover increased for highly water soluble compounds. The new device was used in parallel with a larger, previously developed alveolar air sampler that requires gravity for proper operation; comparable results were obtained with the two units. The device measures 47 x 34 x 11.4 cm and weighs approximately 3.2 kg. Sufficient space is available within the case to accommodate a number of sample collection options.

Life and light: exotic photosynthesis in binary and multiple-star systems.

The potential for Earth-like planets within binary/multiple-star systems to host photosynthetic life was evaluated by modeling the levels of photosynthetically active radiation (PAR) such planets receive. Combinations of M and G stars in (i) close-binary systems; (ii) wide-binary systems, and (iii) three-star systems were investigated, and a range of stable radiation environments were found to be possible. These environmental conditions allow for the possibility of familiar, but also more exotic, forms of photosynthetic life, such as IR photosynthesizers and organisms that are specialized for specific spectral niches.

Concurrent measurement of respiratory and metabolic parameters in rats during exposure to a test vapor: respiratory stress test.

A 75-liter plexiglas chamber has been constructed to simultaneously expose ten rats to a test vapor. Each rat is confined in a small plexiglas plethysmographic box attached to the large chamber. During exposure, the respiration rate, tidal volume, and body temperature are measured. In addition, anaerobic blood samples may be removed through an indwelling catheter in the caudal artery. This sample may be used to measure the amount of a volatile test chemical reaching the blood or to measure blood pCO2, pO2, and pH. This method optimizes animal usage by permitting many sequential measurements on a minimum number of test animals. Since the animals are exposed simultaneously, the interanimal variations in exposure are minimized. Data obtained with this method are reported for rats undergoing a respiratory stress sequence that includes hypoxia and hypercapnia.

Acute inhalation toxicity of 3,3-dimethyl-2-butanol in Sprague-Dawley rats.

Sprague-Dawley rats were given 15, 70 and 140 min exposures to 15 mg/l 3,3-dimethyl-2-butanol, pinacolyl alcohol (PA), or 6-hour exposures to 0.2, 1.0 and 5.0 mg/l PA (1 mg/l = 240 ppm). A 50% mortality rate was obtained at the longest exposure to 15 mg/l. Sex related differences in the blood levels of PA and pinacolone were noted, and the surviving male rats failed to gain weight normally in the first week after exposure. In rats exposed to 5.0 mg/l for 6 hours, there were reductions in horizontal and vertical activity and the minute volume was 55% of controls at the end of exposure. Like many secondary alcohols, PA poses only a possible inhalation hazard; however, male rats may be somewhat more susceptible than females.

Sensory irritation of methylisocyanate vapor.

The respiratory-depression (RD) profile in mice exposed to methylisocyanate (MIC) vapor is reported. The RD50 value calculated from this profile was 2.9 (2.7-3.2) ppm. Concentrations of MIC that have been reported to be unbearable in humans were of approximately the same magnitude as RD50 concentrations in mice for brief exposures.