
Erik VelascoMolina Center for Energy and the Environment
Erik Velasco
PhD
About
127
Publications
78,299
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Introduction
I investigate the impact of urbanization and climate change on the atmospheric environment and biogeochemical cycles, and the conjuncture of these with the construction of sustainable and equitable cities. I'm interested in the interactions between the urban surface and overlying atmosphere in terms of mass and energy exchange, the chemical and physical processes that lead to air pollution, the exposure to pollutants and heat in public spaces, and the impact of urbanization on the carbon cycle.
Additional affiliations
April 2018 - September 2020
National Parks Board (NParks)
Position
- Researcher
Description
- NParks granted me a two year fellowship to wrap up the research projects on the ecological and social benefits provided by urban greenery that I have previously started. I had opportunity to interact with stakeholders and officers, and learn of their operational needs. I led studies on urban carbon sequestration, developed the first set of allometric equations for tropical urban trees, and improved urban soil respiration measurement methods.
September 2008 - August 2010
Position
- PostDoc Position
Description
- I completed a second postdoctoral stay at the National University of Singapore, aiming to learn about scientific research and environmental management in this city-state recognized for its clean environment. I ran an urban canopy heat island monitoring network, built an empirical model of Mexico City's energy balance partitioning, and measured evaporation in an urban water reservoir with an eddy covariance flux system.
February 2006 - August 2008
Position
- PostDoc Position
Description
- After my PhD I did a joint postdoctoral fellowship at the MIT Department of Earth, Atmospheric and Planetary Sciences and the Molina Center for Energy and the Environment (MCE2). I participated in MILAGRO, the largest air quality field campaign in Mexico until today. In this study I coordinated the air pollution and flux measurements conducted at the Escandon site, and I actively participated in communicating the study results to Mexican authorities in multiple workshops and seminars.
Education
September 2002 - December 2005
August 1998 - December 2000
September 1992 - September 1997
Publications
Publications (127)
Motorbikes are by far the dominant mode of transportation in Ho Chi Minh City (HCMC). They solve mobility problems but represent a health risk since riders are directly exposed to noxious exhaust fumes. Hence, face masks emerge as a solution to reduce exposure to harmful particles. The manufacturers of these masks report that they can significantly...
Based on Monin-Obukhov similarity theory and challenging Reynolds analogy, the aerodynamic resistance approach to estimate the transfer of sensible heat (QH) can be used as a proxy to investigate the...
Singapore, as a small but advanced urban economy, has achieved a high-quality living environment and has become an example of a high-density and sustainable city. To maintain that status, Singapore has set a goal of achieving net zero carbon emissions by mid-century and reducing waste sent to landfills by 30% by 2030. To achieve this goal, the Gove...
This book examines the capabilities for monitoring air quality, developing emission inventories, and running chemical-transport models for regulatory, forecasting, and research purposes in Southeast Asia. It also reviews scientific efforts made to better understand and characterize air pollution in the region. Poor air quality poses a threat to pub...
Brown carbon (BrC) is a component of particulate matter which has significant impacts on climate forcing and air quality. To elucidate the current state and sources of BrC in Mexico City, the largest megacity in North America, the aerosols' ability to scatter and absorb light was evaluated over two years in concert with detailed chemical speciation...
Scientific research is at the center of air quality management. Each of its components must be supported by scientific research to provide solid foundations for informed action. This chapter reviews the scientific achievements, challenges, needs, and gaps in the field throughout Southeast Asia. Efforts have focused on understanding the patterns, tr...
Air quality models help explain how pollutants are transported, transformed, and dispersed in the atmosphere. They are useful for analyzing past air pollution episodes and future scenarios that account for changes in emissions and climate, as well as assessing the effectiveness of emission mitigation strategies. A well-tuned air quality model can b...
Delaying the implementation of emission control measures to improve air quality, both locally and regionally, increases the requirements for attaining clean air, the costs associated with breathing unhealthy air, and positive feedback on climate change efforts. There are gaps in air quality management to fill, additional areas to investigate, and e...
Advances in satellite remote sensing technology now enable observations of the atmosphere with unprecedented spatial and temporal resolution, allowing satellites to be used as a complement to ground level air quality monitoring. Nonetheless, the integration of satellite observations into air quality management in Southeast Asia is in its early stag...
Timely, reliable, and accurate data on the ambient concentrations of key pollutants is critical for making informed decisions about public health protection, evaluating the effectiveness of control strategies, and tracking progress toward meeting air quality goals, as well as informing citizens about the quality of the air they breathe and, in the...
Poor air quality is responsible for approximately 335,000 premature deaths in Southeast Asia each year, costing the region 6.75% of its GDP, according to estimates from the Health Effects Institute, the Institute for Health Metrics and Evaluation, and the World Bank. The burden of health damage and monetary cost is not distributed evenly across the...
This chapter provides a brief overview of Southeast Asia and introduces the Association of Southeast Asian Nations (ASEAN), assisting readers to better understand the region’s air quality challenges. It reviews the geography and climate of the region and looks into the economic development, industrialization, and urbanization, as well as the result...
It is critical to know what pollutant species are emitted, where their emission sources are located, and how they evolve over time to design control measures to improve air quality. Emission inventories must provide reliable information to determine the origin of both pollutants directly emitted into the atmosphere and precursor species of secondar...
This chapter describes the methodology and data sources used for the air quality assessments presented in the previous chapter. The State of Global Air report is presumably the most complete source of information available about the current state of air quality in Southeast Asia. It provides a comprehensive analysis of air quality levels and trends...
This chapter summarizes the challenges that Southeast Asia’s air quality management faces nowadays. It discusses how the region’s eleven nations could work together to achieve clean air by improving air quality monitoring, building emission inventories to run air quality models, developing air quality models for both research and regulatory purpose...
Air pollution threatens public health and has a negative impact on people's lives and well-being. Above this, its impact on the environmental sustainability of natural ecosystems and agriculture, as well as its connections to climate change must be considered. This chapter starts off with a concise description of all of adverse effects associated w...
The urgency of climate change confronts our world as a paramount challenge. With approximately 40% of energy-related carbon dioxide (CO2) emissions attributed to infrastructure, buildings, and construction, the need for action is undeniable. In this context, landscape architects, situated at the crossroads of creative thinking and scientific knowle...
This is a summary of a paper published in Environmental Science: Atmospheres that outlines how to map fluxes of CO2 and water vapor at fine spatial resolution in urban neighborhoods using data from an eddy covariance flux tower and mobile measurements in combination with the aerodynamic resistance approach. It was written for a broad audience. The...
Urban surface albedo is an essential biophysical variable in the surface energy balance across all scales, from micro-scale (materials) to the globe, changing with land covers and three-dimensional structures over urban areas. Urban albedos are dynamic over space and time but have not yet been quantified over global scales due to the lack of high-r...
PURPOSE - Waiting for a bus may represent a period of intense exposure to traffic particles in hot and noisy conditions in the street. To lessen the particle load and tackle heat in bus stops a shelter was equipped with an electrostatic precipitator and a three-step adiabatic cooling system capable of dynamically adjust its operation according to a...
Accurate and updated emission inventories of carbon dioxide (CO2) at fine spatial and temporal scales are needed to develop effective strategies to mitigate climate change in urban areas. Similarly, detailed maps of moisture (H2O) giving rise to latent heat (QE) are needed to improve the thermal environment. In order to identify and account for sou...
A total of 20 urban neighbourhood-scale eddy covariance flux tower datasets are made openly available after being harmonized to create a 50 site–year collection with broad diversity in climate and urban surface characteristics. Variables needed as inputs for land surface models (incoming radiation, temperature, humidity, air pressure, wind and prec...
The present study examines the temporal and spatial variability of near‐surface air temperature and the canopy layer urban heat island (UHI) in Singapore. Observations collected at 20 locations across the island city‐state and during 6 years make this one of the most extensive studies carried out in a tropical city. Local climate zones (LCZs), defi...
Based on Monin-Obukhov similarity theory and Reynolds analogy, the aerodynamic resistance approach to estimate the transfer of sensible heat (QH) is used as a proxy to investigate the surface-atmosphere exchange of CO2. As a proof of concept, a bicycle was instrumented to measure georeferenced mixing ratios of CO2 every second along a defined route...
Singapore entered a two-month partial lockdown in April 2020 to curb the spread of COVID-19. The imposed measures in addition to contain the virus spread, cut the emissions of greenhouse gases as many economic activities stopped across the city. The advice of stay-at-home changed the pattern of carbon dioxide (CO2) emissions within the city. To exa...
Twenty urban neighbourhood-scale eddy covariance flux tower datasets have been harmonized and quality controlled, producing a 50 site-year collection with broad diversity in climate and urban surface characteristics. Observations are gap-filled and prepended with 10 years of reanalysis-derived local data to enable use as spin up and forcing for lan...
Esta ponencia de 5 minutos analiza por qué la Ciudad de México no ha progresado en lograr un aire limpio (this 5 min presentation discusses why Mexico City has not progressed in achieving clean air). La ponencia está disponible también en YouTube: https://www.youtube.com/watch?v=VeKaTIwUquo
This 8-min presentation is about personal exposure on public transport in Mexico City. The talk is in Spanish, but the slides are in English. It was given at the workshop on air pollution organized by the MCE2 for CAMe and other environmental agencies in Mexico of April 20-21, 2022. The talk is also available on YouTube: https://www.youtube.com/wat...
The measures taken to contain the spread of COVID-19 in 2020 included restrictions of people's mobility and reductions in economic activities. These drastic changes in daily life, enforced through national lockdowns, led to abrupt reductions of anthropogenic CO2 emissions in urbanized areas all over the world. To examine the effect of social restri...
Water storage plays an important role in mitigating heat and flooding in urban areas. Assessment of the water storage capacity of cities remains challenging due to the inherent heterogeneity of the urban surface. Traditionally, effective storage has been estimated from runoff. Here, we present a novel approach to estimate effective water storage ca...
Model-based studies investigating the spatial and temporal variability of air temperature are commonly employed to assess heat mitigation strategies in cities. To generate reliable predictions, it is therefore important that models are capable to accurately predict air temperature variability across the city to account for the local climate context...
This is a short talk about the potential of urban greenery to directly remove CO2 from the air. The limited knowledge on urban biogeochemistry and a lack of holistic assessments jeopardizes the output of policies promoting greenery to mitigate climate change. Therefore, integral assessments that include plants and soil, and which account for the ca...
This study evaluates a passenger’s exposure to particles and noise on Singapore’s double-decker buses when choosing to travel on the upper or lower deck. Clean and calm journeys are vital to make public buses a choice mode of transport. In the case of Singapore, as in many other cities, double-deckers are in common use and comprise a large fraction...
Singapore entered a two-month partial lockdown in April 2020 to curb the spread of COVID-19. The imposed measures in addition to contain the virus spread, cut the emissions of greenhouse gases as many economic activities stopped across the city. The advice of stay-at-home changed the pattern of carbon dioxide (CO2) emissions within the community. T...
Water storage plays an important role in mitigating heat and flooding in urban areas. Assessment of the capacity of cities to store water remains challenging due to the extreme heterogeneity of the urban surface. Traditionally, effective storage has been estimated from runoff. Here, we present a novel approach to estimate water storage capacity fro...
Increasing urban tree cover is an often proposed mitigation strategy against urban heat as trees are expected to cool cities through evapotranspiration and shade provision. However, trees also modify wind flow and urban aerodynamic roughness, which can potentially limit heat dissipation. Existing studies show a varying cooling potential of urban tr...
Turfgrass is an important component of the urban landscape frequently considered as an alternative land cover to offset anthropogenic CO2 emissions. However, quantitative information of the potential to directly remove CO2 from the atmosphere by turfgrass systems is lacking, especially in the tropics. Most assessments have considered the carbon acc...
Air quality policies based on scientific and technical information are effective for controlling air pollution and protecting public health. Analysis of observations from periodic intensive field studies combined with updated emission inventories, air quality monitoring and numerical modelling can be used to address the causes that trigger air poll...
Weather forecasting models coupled with canopy layer schemes are frequently used to assess the urban heat island (UHI) phenomenon through sensitivity analysis. These models are valuable tools if they are properly tested against field observations. Mughal et al. (2019) (https://doi.org/10.1029/2018JD029796) followed this approach to investigate Sing...
The introduction of aggressive emission control policies propelled three decades ago has led to significant reductions of ozone (O3) levels in the Mexico City Metropolitan Area (MCMA). However, in recent years the levels have stalled, and there is evidence that the production of secondary pollutants may have started to rebound. Similar responses to...
The COVID-19 lockdown has affected our lifestyles and work, forcing us to stay at home. This has strongly reduced road traffic and economic activities particularly in cities, and, consequently, cut down emissions of carbon dioxide (CO2) to the atmosphere. Whilst lockdown does not affect baseline emissions such as ecosystem respiration and CO2 exhal...
Increasing urbanization is likely to intensify the urban heat island effect, decrease outdoor thermal comfort, and enhance runoff generation in cities. Urban green spaces are often proposed as a mitigation strategy to counteract these adverse effects, and many recent developments of urban climate models focus on the inclusion of green and blue infr...
A tropical version of the high‐resolution (300 m) UK Met Office forecast model (UM) using the MORUSES urban canopy parametrization (UCP) is adapted for Singapore. High‐resolution urban surface parameters are determined using a methodology based on Voronoi polygons applied to a 3D building database. The model is evaluated for clear sky and calm cond...
The time a person spends in daily commutes in large cities may represent a major intake of airborne pollutants. In this context, assessments of the variability in exposure to pollutants across transport modes is therefore essential to formulate efficient policies on public health and urban mobility. In this context the present study investigates wh...
Increasing urbanization is likely to intensify the urban heat island effect, decrease outdoor thermal comfort and enhance runoff generation in cities. Urban green spaces are often proposed as a mitigation strategy to counteract these adverse effects and many recent developments of urban climate models focus on the inclusion of green and blue infras...
The dilution effect caused by boundary-layer evolution over land has strong influences on air quality. Accurate and continuous measurements of the boundary-layer height over urban areas are therefore needed for complete air-quality assessments. Commercial ceilometers, in combination with reliable and simple methodologies, can be used to retrieve th...
More than half of the world’s population now lives in cities as a result of unprecedented urbanization during the second half of the 20th century. The urban population is projected to increase to 68% by 2050, with most of the increase occurring in Asia and Africa. Population growth and increased energy consumption in urban areas lead to high levels...
More than half of the world’s population now lives in cities as a result of unprecedented urbanization during the second half of the 20th century. The urban population is projected to increase to 68% by 2050, with most of the increase occurring in Asia and Africa. Population growth and increased energy consumption in urban areas lead to high levels...
Current estimations of the carbon stored by urban trees are usually based on allometric models developed for natural forests. However, urban trees grow in different conditions, and their architecture might differ, thus models developed specially for urban trees are needed. With the aim of improving estimations of carbon storage and sequestration in...
Los vínculos entre la mala calidad del aire y los efectos en la salud pública son evidentes. La contaminación causa daños a corto y largo plazo. Muchas enfermedades respiratorias y cardiovasculares están estrechamente relacionadas con la contaminación del aire, al igual que diversas enfermedades crónicas no transmisibles, que hasta hace poco tiempo...
Este documento propone el trabajo técnico y científico necesario para crear un nuevo paradigma en la gestión ambiental de manera que México pueda contar con las herramientas que permitan diseñar e implementar las políticas ambientales que aseguren el derecho a la salud y un ambiente sano para todos los mexicanos. Se usa como referencia las acciones...
The fireworks activity in Christmas and New Year is the culprit of a substantial increase in the particles pollution during those festivity dates in Mexico City. The fireworks' thrilling explosions fill the air with small particles full of metals and organic and inorganic species, and noxious gases such as sulfur dioxide, nitrogen dioxide, carbon m...
The present study evaluates the performance of the SURFEX (TEB/ISBA) urban land surface parametrization scheme in offline mode over a suburban area of Singapore. Model performance (diurnal and seasonal characteristics) is investigated using measurements of energy balance fluxes, surface temperatures of individual urban facets, and canyon air temper...
Palabras clave: Beneficios y servicios ambientales, bosques urbanos, infraestructura verde y parques y jardines.
In all scientific fields there has been a substantial increase in the proportion of published studies that rely on numerical modeling approaches. Models and techniques that are applied to visualize digital data are increasingly used to assess climatological phenomena such as the urban canopy layer heat island. However, an increasing number of these...
A single layer urban canopy model (SLUCM) with enhanced hydrologic processes, is evaluated in a tropical city, Singapore. The evaluation was performed using an 11-month offline simulation with the coupled Noah land surface model/SLUCM over a compact low-rise residential area. Various hydrological processes are considered, including anthropogenic la...
Exposure concentration and inhaled dose of particles during door-to-door trips walking and using motorized transport modes (subway, bus, taxi) are evaluated along a selected route in a commercial district of Singapore. Concentrations of particles smaller than 2.5 μm in size (PM2.5), black carbon, particle-bound polycyclic aromatic hydrocarbons, num...
To date, existing urban land surface models (ULSMs) have been mostly evaluated and optimised for mid- and high-latitude cities. For the first time, we provide a comparative evaluation of four ULSMs for a tropical residential neighbourhood in Singapore using directly measured energy balance components. The simulations are performed offline, for an 1...
Despite significant efforts, air pollution remains a challenge in Mexico City. Delays to apply environmental policies have fueled the atmospheric reactivity, enhancing the production of ozone (O3) and other secondary pollutants. An increase of 20% in the vehicular fleet over a period of six months coupled with unfavorable meteorological conditions...
Detailed eddy covariance measurements of radiation, energy and carbon dioxide fluxes over a residential neighbourhood of Singapore are presented. The measurements cover a period of ∼7years and represent the longest set of flux data reported for a tropical city. Owing to its equatorial location, the observed radiation fluxes are uniformly high throu...
Transport microenvironments represent hotspots of personal exposure to airborne toxics, particularly of ultrafine particles. Thus, a large exposure may be experienced during daily commuting trips. Amongst these microenvironments, bus stops are critical because of the commuters' close proximity to fresh fumes rich in particles emitted by passing, id...
With the aim to strengthen the verification capabilities of the local air quality management, the air quality monitoring network of Mexico City has started the monitoring of selected non-methane hydrocarbons (NMHCs). Previous information on the NMHC characterization had been obtained through individual studies and comprehensive intensive field camp...
Los desafíos que enfrenta la humanidad ante el calentamiento climático global hacen necesario y urgente entender los ecosistemas desde un punto de vista funcional. En esta perspectiva se preve que los ciclos biogoequímicos de los principales elementos de la vida (carbono, nitrógeno, fósforo o azufre) sean afectados. En este capítulo se resume la in...
El Reporte Mexicano de Cambio Climático es una iniciativa surgida desde el ámbito académico, impulsada y realizada por el Programa de Investigación en Cambio Climático de la UNAM, que se dio a la tarea de convocar, por primera ocasión, al más grande contingente de investigadores provenientes de las diversas disciplinas académicas, instituciones y e...