Harry Alvarez

Harry Alvarez
Universidad Nacional Autónoma de México | UNAM · School of Chemistry

PhD

About

33
Publications
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177
Citations

Publications

Publications (33)
Article
The quantification of total (TC), organic (OC), elemental carbon (EC), and OC/TC, EC/TC ratios is useful to determine the original sources of carbonaceous particles, so the importance of using appropriate standards is often crucial in atmospheric sciences, and the National Institute of Standards and Technology (NIST) offers good analytes. The Stand...
Article
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Capture and emission of carbon dioxide of three species (Buddleia cordata, Senecio praecox and Echeveria gibbiflora) in the Reserva Ecológica del Pedregal de San Ángel (Ecological Reserve of the Pedregal de San Ángel), were estimated. CO2 sampling was carried out in 2010 during the dry (February, March, April and November) and rainy seasons (July t...
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An Aerodyne Aerosol Chemical Speciation Monitor (ACSM; Aerodyne Inc.) was deployed at a site north of Mexico City from November 13, 2013 to April 30, 2014 to investigate the seasonal variability of the chemical composition of submicron particles. The ACSM provides real time information on mass concentration of the non-refractory main species (nitra...
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Agricultural soil erosion, both mechanical and eolic, may impact cloud processes, as some aerosol particles are able to facilitate ice crystal formation. Given the large agricultural sector in Mexico, this study investigates the ice nucleating abilities of agricultural dust collected at different sites and generated in the laboratory. The immersion...
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Black carbon (BC), a component of carbonaceous material, has an important role in the environment, and it is considered a short-lived climate forcer that plays a vital role in the global climate system. BC concentrations were analyzed during 2017 in two sites in Mexico, Juriquilla and Altzomoni, which have different emission sources and atmospheric...
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The continuous and sustained population shift from rural to urban areas is driving most of the fast-growing megacities on a global scale. Considerable pollution, gases and particulate matter, is emitted yearly into the atmosphere of megacities, with unclear impacts on the local and regional hydrological cycle. The present work evaluated the inter-a...
Preprint
Full-text available
Agricultural soil erosion, both mechanical and eolic, may impact cloud processes as some aerosol particles are able to facilitate ice crystals formation. Given the large agricultural sector in Mexico, this study investigates the ice nucleating abilities of agricultural dust collected at different sites and generated in the laboratory. The immersion...
Article
Full-text available
More than 7 thousand wildfires were recorded over Mexico in 2019, affecting almost 640 thousand hectares. Most of these fires occurred during the spring season generating dense smoke plumes, impacting urban areas in the central part of the Mexican plateau. From May 10 to 17, 2019, biomass burning (BB) plumes affected Mexico City (MC) and diffused a...
Preprint
Full-text available
More than 7 thousand wildfires were recorded over Mexico in 2019, affecting almost 640 thousand hectares. Most of these fires occurred during the warm-dry season generating dense smoke plumes, impacting urban areas in the central part of the Mexican plateau. From May 10 to 17, 2019, biomass burning (BB) plumes affected Mexico City (MC) and diffused...
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Biomass burning (BB) emissions and African dust (AD) are often associated with poor regional air quality, particularly in the tropics. The Yucatan Peninsula is a fairly pristine site due to predominant trade winds, but occasionally BB and AD plumes severely degrade its air quality. The African Dust And Biomass Burning Over Yucatan (ADABBOY) project...
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Most precipitation from deep clouds over the continents and in the intertropical convergence zone is strongly influenced by the presence of ice crystals whose formation requires the presence of ice nucleating particles (INPs). Although there are a large number of INP sources, the ice nucleating abilities of aerosol particles originating from oceans...
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On a global scale, African dust is known to be one of the major sources of mineral dust particles, as these particles can be efficiently transported to different parts of the planet. Several studies have suggested that the Yucatán Peninsula could be influenced by such particles, especially in July, associated with the strengthening of the Caribbean...
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This study focuses on the air quality evaluation of Merida, a medium-size city located in the Yucatan Peninsula with a significant population growth in recent years. Particle-bound Polycyclic Aromatic Hydrocarbons (pPAHs) were quantified with a real time sensor during a six-month period during the dry season (October 2017 to March 2018). The pPAHs...
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Ice nucleating particles (INPs) induce ice crystal formation and therefore, they are able to influence precipitation development. INP sources remain highly uncertain, with most of the observational studies performed in mid- and high-latitudes, bypassing the Tropics. In the present study, rainwater, cloud water, and aerosol samples were collected du...
Preprint
Full-text available
Most precipitation from deep clouds over the continents and in the intertropical convergence zone is strongly influenced by the presence of ice crystals, whose formation requires the presence of ice nucleating particles (INP). Although there are a large number of INP sources, the ice nucleating abilities of aerosol particles emitted from oceans, de...
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Full-text available
Aerosol particles have been shown to trigger cardiovascular and respiratory diseases in populations living in polluted regions, depending on their size and composition. Although fine aerosol particles have been found to reach the lungs and the blood stream, their acute effects are related to the fraction of ultrafine aerosol particles (i.e., UFPs,...
Preprint
Full-text available
On a global scale, African dust is known as one of the major sources of mineral dust particles as they can be efficiently transported to different parts of the planet. Several studies have suggested that the Yucatan Peninsula could be influenced by such particles, especially in July, associated with the strengthening of the Caribbean low level jet....
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Full-text available
The concentration of biological particles in the atmosphere is widely variable because it depends on several meteorological and geographical factors. Meteorological conditions in tropical coastal cities are unique due to both marine and terrestrial influences that can strongly modify the concentration and diversity of airborne microorganisms. Never...
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Optical properties of atmospheric particles at Mexico City (UNAM) and Queretaro (JQRO) were measured with a Photoacoustic Extinctiometer (PAX) at 870 nm. The Mexico City Metropolitan Area has around 21 million inhabitants and Queretaro Metropolitan Area has little more than a million. Observations of meteorological parameters (relative humidity, so...
Article
Particle size distributions in the 10–400 nm diameter size range were measured at a site south of Mexico City, during 30 non-consecutive days from October to December 2016 using a Scanning Mobility Particle Sizer, together with meteorological parameters and criteria pollutants concentration. Particles were classified into three modes depending on t...
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Atmospheric black carbon concentrations were measured at two urban sites (Mexico City and Monterrey), one suburban site (Juriquilla) and one high-altitude site (Altzomoni) in Mexico during 2015 and part of 2016. Black carbon concentrations were compared against other criteria gases finding a strong correlation with carbon monoxide at the urban site...
Article
Atmospheric black carbon concentrations were measured at two urban sites (Mexico City and Monterrey), one suburban site (Juriquilla) and one high-altitude site (Altzomoni) in Mexico during 2015 and part of 2016. Black carbon concentrations were compared against other criteria gases finding a strong correlation with carbon monoxide at the urban site...
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Atmospheric aerosol particles that can nucleate ice are referred to as ice-nucleating particles (INPs). Recent studies have confirmed that aerosol particles emitted by the oceans can act as INPs. This very relevant information can be included in climate and weather models to predict the formation of ice in clouds, given that most of them do not con...
Article
During the warm-dry season (March-May) of 2016 and 2017, Mexico City experienced high ambient concentrations of particulate matter and ozone resulting in levels well above both national and international standards. Mexico City lives under a volatile organic compounds (VOC) limited system; that is, the formation of O3 has been determined to be in th...
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We measured and compared mercury (Hg) and other ions in rainwater collected in San Joaquin (mining zone) and Juriquilla (urban area), central Mexico, from 2009 to 2012. A total of 274 rainwater samples were collected and analyzed for pH, electrical conductivity, [Formula: see text] Cl-, [Formula: see text] Na+, K+, Ca2+, Mg2+ and Hg. Mercury concen...
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The "Aerosoles en Ciudad Universitaria 2015" (ACU15) campaign was an intensive experiment measuring chemical and optical properties of aerosols in the winter of 2015, from 19 January to 19 March on a site in the south of Mexico City. The mass concentration and chemical composition of the non-refractory submicron particulate matter (NR-PM1) was dete...
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During the MILAGRO campaign, March 2006, eight-stage cut impactors were used to sample atmospheric particles at Tecámac (T1 supersite), towards the northeast edge of the Mexico City Metropolitan Area, collecting fresh local emissions and aged pollutants produced in Mexico City. Particle samples were analyzed to determine total mass concentrations o...
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Emission factors and personal exposure measurements were obtained in the working environment of a brick kiln yard in the municipality of Victoria de Durango, Mexico. Two kinds of kiln were evaluated; one was a fixed traditional kiln (FTK); the other was a local variation of an improved kiln called the ecological Marquez brick kiln (MK2). To disting...
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Introduction: Dysphania graveolens is used mainly in Mexican traditional medicine against gastrointestinal ailments. Previous investigations revealed that its flavonoids are important active principles; however, there is not a reliable and accurate analytical method for determining these compounds in the crude drug or preparations of the plant. In...

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Projects

Projects (5)
Project
This project aims to characterize the chemical, physical, optical, and biological properties of locally emitted and long-range transported aerosol particles to evaluate their impacts on air quality and human health in Mexico and other Tropical countries.
Project
To determine what are the main drivers in the development of precipitation in the Valley of Mexico
Project
This project aims to identify the main sources of aerosol particles in the Yucatan Peninsula with a special focus on biomass burning and African dust particles. The first intensive sampling period will focus on the characterization of the BB plumes, whereas at the end of the campaign the Saharan dust plumes are more likely to be observed in the region. Marine aerosol particles and biological particles (both continental and maritime) are expected to be present during the whole sampling period. Objectives: 1. Characterize the chemical composition of the aerosol particles arriving to Merida to infer their main sources. 2. Quantify the influence of BB particles in the air quality of Merida. 3. Determine the toxicity and the health risk of the aerosol particles in Merida. 4. Quantify the main sources of CCN and INPs around Merida. 5. Examine the influence of BB particles on the local hydrological cycle. 6. Estimate if mineral dust particles from the Saharan desert can reach Merida. 7. Identify the biological microorganism present in the Saharan dust and biomass burning plumes. 8. Contribute to the understanding of the impact of African Dust as part of the Caribbean Aerosol and Heath Network (CAHN): http://journals.ametsoc.org/doi/abs/10.1175/BAMS-D-12-00142.1