Mexico City Metropolitan Area Research Articles

Faith, Work, and Reciprocity: Listening to Mexican Men Caregivers of Elderly Family Members.

The purpose of this qualitative study was to examine the role of Mexican men caregivers of older adults. Studies investigating male caregiving practice in Mexico are lacking. Listening events for older adults and family caregivers were held in six cities, obtaining an ethnically and socioeconomically diverse sample of 121 participants-81 older adults and 57 primary caregivers (including 17 older adults). Focus groups discussed end-of-life issues and challenges of care. Discussions were audio recorded and field notes were made. Framework Analysis was used to analyze data. Nationally, 37% of the caregivers were men. In the metropolitan area of Mexico City, 57% of caregivers were men. The men caregivers discussed their roles and experiences. The results were categorized into three themes: (a) reciprocity in family caregiving, (b) a practical work-oriented attitude toward caregiving, and (c) strong religious faith. Caregiving formed an important part of their masculine role. Stereotypes related to gender and care should be reexamined. Further research is needed to explore gender variations in caregiving, evolving gender roles, and needs for support and services.

Toddler temperament and prenatal exposure to lead and maternal depression.

BackgroundTemperament is a psychological construct that reflects both personality and an infant’s reaction to social stimuli. It can be assessed early in life and is stable over time Temperament predicts many later life behaviors and illnesses, including impulsivity, emotional regulation and obesity. Early life exposure to neurotoxicants often results in developmental deficits in attention, social function, and IQ, but environmental predictors of infant temperament are largely unknown. We propose that prenatal exposure to both chemical and non-chemical environmental toxicants impacts the development of temperament, which can itself be used as a marker of risk for maladaptive neurobehavior in later life.In this study, we assessed associations among prenatal and early life exposure to lead, mercury, poverty, maternal depression and toddler temperament.MethodsA prospective cohort of women living in the Mexico City area were followed longitudinally beginning in the second trimester of pregnancy. Prenatal exposure to lead (blood, bone), mercury, and maternal depression were assessed repeatedly and the Toddler Temperament Scale (TTS) was completed when the child was 24 months old. The association between each measure of prenatal exposure and performance on individual TTS subscales was evaluated by multivariable linear regression. Latent profile analysis was used to classify subjects by TTS performance. Multinomial regression models were used to estimate the prospective association between prenatal exposures and TTS performance.Results500 mother-child pairs completed the TTS and had complete data on exposures and covariates. Three latent profiles were identified and categorized as predominantly difficult, intermediate, or easy temperament. Prenatal exposure to maternal depression predicted increasing probability of difficult toddler temperament. Maternal bone lead, a marker of cumulative exposure, also predicted difficult temperament. Prenatal lead exposure modified this association, suggesting that joint exposure in pregnancy to both was most toxic.ConclusionsMaternal depression predicts difficult temperament and concurrent prenatal exposure to maternal depression and lead predicts a more difficult temperament phenotype in 2 year olds. The role of temperament as an intermediate variable in the path from prenatal exposures to neurobehavioral deficits and other health effects deserves further study.

El robo de vehículos y su relación espacial con el contexto sociodemográfico en tres delegaciones centrales de la Ciudad de México (2010)

AbstractThis paper analyzes the spatial patterns of motor vehicle theft crimes in Mexico City. The largest metropolitan áreas in Latin-America are witnessing a sharp escalation of urban violence and the Metropolitan Area of Mexico City is not the exception. In the Metropolitan Area of Mexico City the motor vehicle theft is one of the crimes that have higher arrest and criminal warrants with 40 336 in average during the 1995 to 2007 period. In 2010 motors vehicle theft reached 44 446 criminal warrants, representing the 39% of all criminal warrants in the city. However, such crime does not show a homogenous spatial pattern but shows a high spatial concentration in some delegations of Mexico City such as Benito Juárez, Coyoacán and Cuauhtémoc. In this context, the research question is: Does exists spatial relationship between concentration of motor vehicle theft and environmental factors?. The theoretical background is provided by the social disorganization theory, the routine activities and crime patterns. Both theories explain criminal spatial variation as responses to environmental conditions. The causal mechanism underlying both theories is that individuals make decisions based on the aggregated behavior around them. Individuals are constantly exposed to social stimuli, and they make use of the information derived from the environment (e.g. behavioral contagion).The data includes arrests and criminal warrants of motor vehicle theft provided by the General Office of Justice of the Federal District (PGJDF, 2010) and the rest of socioeconomic variables were provided by the Housing and Population Census, 2010, all of them at census tract level. The methodology used includes regional analysis techniques such as location quotient, múltiple regression analysis and exploratory spatial data analysis ESDA in specific the Morán Indice. This is performed within reasonable limits of data reliability, sampling error, and in disconnection from theoretical postulates. The results of the múltiple regression identify variables such as none residential land use, population density, female-headed households, single and concentration of young population influence motor vehicle theft crimes. These findings allow us to design public security polices focused in places where could implement programs oriented to the situational prevention of the crime and the social prevention of crime. Besides, the results provide findings for urban planning and social development policies with police strategies.

Abortion Legalization and Childbearing in Mexico.

In 2007 abortion was legalized in the Federal District of Mexico, making it the largest jurisdiction in Latin America, outside of Cuba, to allow women to have abortions on request during the first trimester of pregnancy. While the implications of the law for women's health and maternal mortality have been investigated, its potential association with fertility behavior has yet to be assessed. We examine metropolitan-area differences in overall and parity-specific childbearing, as well as the age pattern of childbearing between 2000 and 2010 to identify the contribution of abortion legalization to fertility in Mexico. Our statistical specification applies difference-in-difference regression methods that control for concomitant changes in other socioeconomic predictors of fertility to assess the differential influence of the law across age groups. In addition, we account for prior fertility levels and change to better separate the effect of the law from preceding trends. Overall, the evidence suggests a systematic association between abortion legalization and fertility. The law appears to have contributed to lower fertility in Mexico City compared to other metropolitan areas and prior trends. The influence is mostly visible among women aged 20-34 in connection with the transition to first and second child, with limited impact on teenage fertility. There is some evidence that its effect might be diffusing to the Greater Mexico City Metropolitan area.

Inequality and Spatial Convergence in the Mexico City Metropolitan Area, 1989-2010

The analysis of inequality and polarization patterns between by regions of a national economy is central to ascertain their possibilities of future economic development. In this work we study such patterns in municipalities and boroughs of Mexico City Metropolitan Area (Zona Metropolitana de la Ciudad de Mexico, ZMCM). The evolution of inequality and polarization in this important area of Mexico is studied with new proposals of measurement using spatially conditioned indexes and through a dynamic transition analysis. The results confirm that the territorial inequality has grown among the municipalities and boroughs that integrate the ZMCM. Moreover, this phenomenon coincides with an increase of the polarization characterized by the formation of four subgroups or convergence clubs.

Spatial Interaction Regional Model for the Mexican Economy (SIRMME): A Special Case for Mexico City Metropolitan Area

This paper analyzes empirically a macro model and a regional model to explain Mexico and Mexico City economies respectively. Typically, regional economic modeling considers either a top-down or bottom-up approach to model regional difference in economic growth. This paper shows results that explain regional difference in Mexico from the bottom-up through a special case that focuses on the spatial interaction between Mexico City -the main economic engine of Mexico- and the rest of the country during the period 2000-2010. Our results indicate that variables associated with human capital, internal migration, "creative class", micro-firms and spatial interaction among micro-regions were conditioning the differential growth between Mexico City and the whole country during the period 2000-2010. Likewise, we present econometric results of a typical macro model that explains economic growth in Mexico by different income effects on components of aggregate demand during the period 1993-2010. The purpose of both exercises is to motivate future research for the Mexican case to link macro components (such as export driven forces, Mexico´s dependency to the USA´s business cycle, loss of government spending, etc.) with their local counterparts such as agglomeration economies, human and creative capital stock, regional spillovers, natural resources, dynamic population, etc. to explain regional differential growth.

ESTUDIO DEL VALOR INDICADOR DE LAS COMUNIDADES DE ALGAS BENTÓNICAS: UNA PROPUESTA DE EVALUACIÓN Y APLICACIÓN EN EL RÍO MAGDALENA, CIUDAD DE MÉXICO

The application and development of environmental laws governing watershed management requires identification of biological indicators, parameters and measures to establish its ecological status, for which the present study aims to characterize the ecological indicator value of stream benthic algae in an urban area of Mexico City. Six sites of the Magdalena river were studied in the most contrasting seasons: dry-warm, rainy and dry-cold. At each site the physicochemical parameters of water were recorded and 10 samples were collected: Five with visible algal growths and five with diatoms. The environmental quality of each site was determined by the trophic status and its confirmation with the richness and benthic algal diversity, through a canonical correspondence analysis and the calculation of the indicator value of species (IndVal). According to the trophic status, three groups of sites were recognized. The first group (G1) was assessed as reference of the oligotrophic conditions and presented 11 species with the highest IndVal, protruding: Encyonema silesiacum, Gomphonema parvulum, Navicula cryptocephala, Planothidium lanceolatum, Vaucheria bursata, Placoma regulare and Nostoc parmelioides. A second group (G2) was associated with 15 species considered detectors, which were tolerant to increased nutrients in at least one season, such as Diatoma mesodon and Prasiola mexicana. The third group (G3) included sites with species that had a wide range of tolerance to pollution: Fistulifera saprophila , Nitzschia minuta , Nitzschia palea , Nitzschia recta and Phormidium autumnale. The species IndVal of Magdalena River has established reference sites of good environmental quality and those that are altered by human activities, therefore they are recommended as the first step in a methodological proposal for a long-term biomonitoring through a biological index.

Loss of a lake system in a megacity: The impact of urban expansion on seasonal meteorology in Mexico City

AbstractThe Mexico City Metropolitan Area (MCMA) has undergone significant urban expansion in a closed basin that once supported a large lacustrine system. While urbanization has been mentioned as a factor in observed meteorological trends, a systematic study of the effects of land use‐land cover change (LULCC) on seasonal meteorology is lacking. In this study, we utilize the Weather Research and Forecasting (WRF) system to determine the spatiotemporal changes in near‐surface air temperature, precipitation, and boundary layer conditions induced by the modern‐day urban landscape relative to presettlement conditions. We capture the MCMA extent through an improved Landsat‐based multicategory urban classification and therefore account for intraurban spatial heterogeneity and further conduct additional experiments to examine the sensitivity to anthropogenic heating within WRF. We find that accounting for these factors produced the best simulations of thermal conditions, with RMSE values less than 1.5°C at all measurement stations, and an improved diurnal cycle of air temperature and precipitation. We then assessed the impacts of LULCC in the MCMA, finding that thermal changes were largest during daytime hours, with temperature increasing, on average, by more than 4°C. Furthermore, we utilize these simulations to mechanistically link the built environment‐induced increase in air temperature to simulated increases in rainfall during the evening hours. To our knowledge, this study provides the first dynamical and thermodynamical evidence to support the rainfall enhancements documented through observations in the MCMA and link it quantitatively to the warming effects associated with urbanization. These results have important implications for understanding the meteorological conditions leading to widespread urban flooding in the MCMA.

Popularidad y relaciones entre iguales en el aula: un estudio prospectivo

This paper analyzes in depth the network of popularity among classmates and the connections that this phenomenon maintains with different kinds of relationships (i.e., positive, neutral, and negative) that take place within the classroom. We use Social Network Analysis (SNA) to identify interaction contexts in the classroom. Different kinds of relationships in 20 classrooms from two secondary schools located in the suburban area of Mexico City were assessed. The research data was provided by 660 students (67% girls; 33% boys). Cohesion measures were calculated for positive, neutral, negative, and popularity networks. Cluster analysis shows two profiles based on structural properties of the networks that we have called “Neutral Symmetric” and “Positive Asymmetric”. The first one presents low homophily relative to sex, predominance of positive and neutral relationships, and a significant level of negative links. The second profile presents a heterogeneous distribution according to sex, high homophily and high rates of cohesion in positive relationships. Regression analysis shows that the number of students per class is negatively related to the positive network density, and positively related to the negative network density. The simultaneous comparison of multiple networks shows that popularity is associated with being immersed in positive relationships. By contrast, the data suggest certain incompatibility between being popular and being immersed in negative relationships. The findings are discussed in order to improve school life and public policies in education.

Temporal and Spatial Variations of Atmospheric Radiocarbon in the Mexico City Metropolitan Area

The Mexico City Metropolitan Area (MCMA) produces a complex mixture of gases and aerosols from diverse sources, including burning of fossil fuels, biomass, and wastes, with a significant biogenic contribution. We present the first results of ongoing projects to study temporal and spatial variations of 14 CO 2 in the area. Temporal variations reconstructed from tree rings of Taxodium mucronatum indicate a considerable radiocarbon depletion, in accordance to the vast amount of fossil fuels burnt inside Mexico Valley, with values between 62 and 246‰ lower than background values for the 1962–1968 period, and lower by 51–88‰ for the 1983–2010 period. The lower dilution found for the last decades might indicate an increase in enriched 14 CO 2 sources. Results from the spatial distribution, as revealed from integrated CO 2 samples and grasses from six points within the MCMA collected during the 2013 dry season, show variations between sites and sample types. For integrated CO 2 samples, values range from 35.6‰ to 54.0‰, and for grasses between –86.8‰ and 40.7‰. For three of the sampling points, the grasses are significantly depleted, by up to ~133‰, as compared to the corresponding integrated CO 2 sample. This may result from differences in the carbon assimilation period and exposure to different CO 2 sources. Higher-than-background Δ 14 C values were found for all integrated CO 2 samples, presumably resulting from 14 C-enriched CO 2 derived from forest fires in the mountains during the sampling period. Results obtained so far confirm the complexity of the 14 C cycle in the MCMA. DOI: 10.2458/azu_rc.57.18360

Coronado-era Place-names, II. “Chichilticale” and the Origin of the Name of the “Chiricahua” Mountains

A Coronado-era name, variously spelled as “Chichiltecally,” “Chichilticale,” etc., was applied in 1540 to a mountain range, a ruin, and the surrounding area in southeast Arizona. Today it is usually described as a Nahuatl word assigned to a red-colored pueblo ruin on the Coronado route to Cíbola. We note, however that the chronicler Jaramillo, with the lead portion of the Coronado expedition, assigned “Chichiltecally” solely to a mountain range and associated pass. Recent archaeological finds indicate that the ruin was at the west base of the Chiricahua Mountains and south of Apache Pass. We show that the name recorded by Jaramillo was an attempt to render an Ópata term connoting “Mountain Range of Many Turkeys,” and that this name evolved through various spellings to “Chiricahua,” which essentially means “Turkey Mountain.” Application of a similar Nahuatl term to the ruin may have arisen from a misunderstanding or adaptation of the Ópata term by Nahuatl speakers on the Coronado expedition, or it may have been interpreted as the “correct” native name after the chroniclers returned to the Nahuatl-dominated Mexico City area.

Contribution of Biomass Burning to Carbonaceous Aerosols in Mexico City during May 2013

ABSTRACTDuring the springtime fire season, wildfires and agricultural burning represent a potentially large contribution to air quality degradation in the Mexico City Metropolitan Area (MCMA). PM10 filter samples were collected at six different stations in May 2013, the month with the maximum reported regional fire counts from 2002 to 2013. Two regimes were identified considering changes in predominant wind direction and precipitation patterns inside MCMA. The filter samples were analyzed for water-soluble organic carbon (WSOC) and the biomass burning tracers including levoglucosan (LEV) and water-soluble potassium (WSK+). LEV concentrations correlated positively with ambient concentrations of PM2.5 and PM10 (R2 = 0.61 and R2 = 0.46, respectively). Strong correlations were also found between WSOC and LEV (R2 = 0.94) and between WSK+ and LEV (R2 = 0.75). PM2.5 accounted for 60% of the PM10 mass concentrations. Our speciated measurements accounted for 37% of the total PM10 mass concentration and ~60% of the PM2.5 mass concentrations; the missing mass was attributed to crustal material (soil or dust) and carbonaceous aerosols that were not segregated into the WSOC fraction. Average LEV/WSOC ratios ranged from 0.015 in the first, smokier and drier part of the month, to 0.006 during the rainier end of the measurement period. Using previously reported LEV/WSOC emissions ratios, the estimated biomass burning contributions to WSOC ranged from 7–23% assuming LEV is stable in the atmosphere, and 8–57% when accounting for LEV photochemical degradation in the atmosphere. Thus, our findings indicate that primary emissions from biomass burning sources represent significant contributions to ambient WSOC and PM in MCMA during the springtime fire season.

Canine Herpesvirus Seroprevalence and Associated Factors in Dogs of Mexico

Canine herpesvirus (CHV-1) causes disease associated with high mortality in infect-ed puppies, which represents large financial losses for dog breeders. Since CHV-1 at the time of the study he had not been reported in Mexico, the main objective of this study was to determine the prevalence of antibodies against CHV-1 in canine kennels in the metropolitan area of Mexico City. A commercial enzyme-linked immuno-sorbent assay (ELISA) was used, and the results were compared to those of a viral neutralization test. The ELISA kit uses the complete viral particle as the antigen. The plaque reduction neutralization test was combined with the immunoperoxidase technique because of the low cytopathic effect of CHV-1. Neutralizing antibodies were also detected in 20 randomly selected samples. The prevalence of CHV-1 with ELISA was 87%. The concordance between ELISA and serum neutralization (SN) was 0.1129, the sensitivity of the ELISA against SN was 1.0 (100%), the positive predic-tive value was 0.39 (39%), and the negative predictive value was 1 (100%). These results show that ELISA is useful for monitoring the dog population for CHV-1; a positive test result requires confirmation with an SN test, and a negative ELISA result indicates a high probability of being SN-negative. The only variables that were sta-tistically associated with CHV-1 prevalence were breed and kennel. A statistically significant relationship between the degree of ELISA and SN titer was obtained, with a confidence level of 95%. None of the clinical presentation factors was statistically significant. These results suggest that most of the canine population studied in Mex-ico is in a herpesvirus latency state.

Modeling Urban Transfer Stations Efficiency

Efficiency estimation of transit transfer stations (TTS) in densely populated urban areas is a mandatory step to define proper sustainable public transportation networks. However, due to the lack of data and the complexity of the operation patters, efficiency assessment is a cumbersome task in practice. This paper presents a novel approach to establish relative efficiencies in order to optimize TTS operation and design. Using the Data Envelopment Analysis method (DEA) three key efficiency dimensions are studied, which corresponds to the pillars of sustainability: technical, social and environmental. Efficiencies were computed using a database generated including 39 TTS located in Mexico City Metropolitan Area. Results show that none of the stations analysed are completely efficient considering the three dimensions simultaneously. Technically efficient TTS are those attending the highest number of passengers in a smallest given area. Social efficient TTS are those that provide enough services, such as automatization, multiple transport modes, and low transfer time, leading to high levels of users satisfaction. Finally, environmental efficient TTS correspond to those registering low values of air polluting emissions per passenger mainly due to the presence of non-oil fuel transport modes. In developing countries in Latin American and Asia, the application of this kind of models represent an excellent tool for the computation and understanding of TTS operations.

Quantifying the Impacts of Sustainable City Logistics Measures in the Mexico City Metropolitan Area

This paper discusses the assessment of the potential impacts of a number of city logistics measures proposed for the Metropolitan Area of the Mexico City Valley: off-hour delivery programs; policies and agreements to increase cargo consolidation and decrease empty trips; and the implementation of preferential truck routes. The analyses consider the impacts on travel distances, travel times, accidents, emissions and health impacts. In doing so, the authors discuss the proposed measures, the assumptions used to estimate the impacts, and the information required. Different scenarios are evaluated for the various measures.

Implications of Climate Change on Water Resource Management in Megacities in Developing Countries: Mexico City Case Study

<p class="emsd"><span lang="EN-GB">More than half of the world’s population currently lives in urban areas. The fastest growing megacities are occurring mainly in developing countries, where stresses on water systems already pose major challenges for governments and water utilities. Climate change is expected to further burden water resource management, putting at risk governments’ ability to guarantee secure supplies and sustainable development. In this study, the significance of assessing the implications of climate change on water resources in megacities as an important component of the adaptation process is explored. The Mexico City Metropolitan Area (MCMA), one of the largest cities in the world, is presented as a case study. The downscaled outputs of the General Circulation Model GFDLCM2a for the A1B and B1 gas emissions scenarios for the period 2046–2081 and a statistical model were used to simulate the likely impacts of climate change in water resources and domestic water demand. The results showed that an increase in temperature and changes in precipitation patterns could increase household water demand for both scenarios, between 0.8% and 6.3% in the MCMA. The future projections also estimated increases of 150% and 200% in events with rainfall intensity of more than 60 mm d<sup>-1</sup> and 70 mm d<sup>-1</sup> respectively, drawing attention to the critical impacts these changes may have on flood events. Despite the uncertainty of models projections, future climate change scenarios have proven to be a flexible guide to identify vulnerabilities of water resources and support strategic adaptation planning. In order to increase their adaptive capacity and resilience to the effects of an uncertain climate change, megacities should consider implementing an integrated water resources management approach that creates opportunities through adequate policies, new technologies, flexible frameworks and innovative actions. </span></p>

Water and the political ecology of urban metabolism: the case of Mexico City

Today, 52% of the world's population live in urban areas and this number is expected to rise to 64-69% by 2050. Cities consume most of the world's energy and materials, and are responsible of about three quarters of direct and indirect GHG emissions. Consumption patterns, however, are asymmetrical among cities and citizens. Urban metabolism, or the analysis of energy and material flows and stocks (infrastructure) that shape settlements, allows the identification not only of the dimensions of these flows and stocks, but also their main technical and socio-ecological features. These can also be evaluated from an urban political ecology perspective, that is, in terms of power relationships that define who gets access to, or control over, natural resources and other components of urban space. This article opens with a general introduction to urbanization trends, followed by a presentation of urban metabolism and urban political ecology approaches as useful analytical tools for assessing the access, management and usufruct of water in Mexico City's Metropolitan Area. A general description of the hydropolitan region of study is then offered in order to analyze urban water flows and their socioecological implications for the water-energy nexus and climate. The article concludes with a call for a paradigm change in order to transform urban settlements towards more livable, sustainable and equitable ones; a process that demands not only paying attention to the form but also to the function of urban territories within capitalist productive relationships. In this context the design and execution of public policies needed for transforming the current trend of constructing, operating, managing, and living in cities must be proactive, imaginative, and based on an integral metabolic planning that allows the adjustment of planning and policy tools to overarching contextual changes and to historical trends and socially desirable futures. Specific recommendations include the bottom-up management of water infrastructure and the guarantee of human rights to water, sanitation and a healthy environment; these are components of the 'right to the city.'Key words: urban metabolism, water, water-energy nexus, climate change, urban political ecology, Mexico City

The ~ 2000 yr BP Jumento volcano, one of the youngest edifices of the Chichinautzin Volcanic Field, Central Mexico

Abstract The Chichinautzin Volcanic Field is situated at the southern limit of the Basin of Mexico and the Metropolitan area of Mexico City, the third most populated city around the world. The Chichinautzin Volcanic field holds more than 220 monogenetic volcanoes. Xitle is the youngest of these with an estimated age of 1.6 ky BP. Xitle's eruptive activity took place during the Mesoamerican Mexican Pre-classic period and is related to the destruction of Cuicuilco Archaeological Site, the oldest civilization known in Central Mexico. However, there are still several regional cones that have not been dated. Based on 14 C ages, stratigraphic and geomorphologic criteria, we conclude that the Jumento volcano, located to the west of Xitle, is one of the youngest cones of the Chichinautzin Volcanic Field. The Jumento volcano has a basaltic andesite composition, and its eruptive activity was initially hydromagmatic, followed by Strombolian and finally effusive events occurred recorded through: (1) a sequence of hydromagmatic pyroclastic surges and ashfall layers emplaced at a radius of > 5 km from the crater with charcoal fragments at its base; this activity built the Jumento's cone with slopes of 32°; and (2) lava flows that breached the southern part of the cone and flowed for up to 2.5 km from the vent. The resulting 14 C ages for this volcano yielded a maximum age of ~ 2 ky BP. Morphometric analysis indicates that the state of degradation of Jumento cone is similar to the Xitle, suggesting that the Jumento could be in the state of degradation of a volcanic structure of similar age or younger adding credence to the probable radiocarbon age of ~ 2 ky BP for the Jumento edifice.

Diurnal variations of airborne pollen concentration and the effect of ambient temperature in three sites of Mexico City.

Pollen is an important cause of allergic respiratory ailments in the Mexico City Metropolitan Area (MCMA). However, very little is known if ambient air temperature correlates with the early blooming of plants observed in other urban areas around the world. A research study was conducted during the dry season of 2012-2013 at three representative sites of the MCMA with different urban characteristics with the aim to understand the relationships between the profusion and diversity of pollen against temperature and other meteorological variables and degree of urbanization. Pollen samples were collected using a Hirst-type trap sampler in the sites: Merced (highly urbanized), Iztapalapa (medium-high urbanized) and Coyoacan (moderately urbanized). Urbanization levels were determined using a composite index based on population density, proportion of surface covered by construction and asphalt, and urban heat island intensity. A set of representative pollen sampling tapes were assayed under a light microscope at magnification of ×1,000 and converted to grains per cubic meter. The most representative pollen types found in the three sites were, regardless of urbanization levels were: Fraxinus, Cupressaceae/Taxodiaceae, Casuarina, Alnus, Myrtaceae, and Pinus. Total pollen concentration was greatest in the moderately urbanized area, although earlier blooming took place at the highly urbanized zone. Total pollen concentration in the medium-high urbanized site has the lowest because the green areas in this zone of MCMA are few. In a diurnal basis, the most abundant pollen types peaked near midday or in the afternoon evening at the three sites. A Spearman test showed a positive correlation among bihourly pollen concentrations, temperature and relative humidity in all sites, but wind speed just correlated in Iztapalapa and Coyoacan. The results obtained suggest that Urban Heat Island Intensity can disturb flowering periods and pollen concentrations, largely in the highly urbanized areas. A principal components analysis established that the concentrations of each pollen type differed across the urbanization gradients. Additionally, it was found that a large number of allergenic pollens are produced by ornamental trees, some only recently introduced by urban planners.

Environmental policies in the peri-urban area of Mexico City: The perceived effects of three environmental programs

Managing peri-urban areas is complicated due to the unique rural and urban characteristics and because sectorial policies are not always compatible. In Mexico City, peri-urban spaces (particularly the Conservation Zone in the south of the city) provide important ecosystem services for urban residents. However, despite this environmental importance, the Conservation Zone suffers from land-use changes as a result of the economic transition from rural to urban activities. Different government agencies have implemented environmental programs attempting to address this problem. The present paper focuses on the beneficiaries' perceptions of the effects of three such programs. The results demonstrate the importance of the conservation programs but at the same time show numerous unresolved issues, including excessive administrative fulfillments, social and political conflicts, and a lack of coherence among programs. An alternative could be an integrated spatial and environmental planning process in which federal and local authorities, beneficiaries, and city inhabitants participate.