Teresa Vera

Centro de Estudios Ambientales del Mediterráneo | CEAM · EUPHORE

Air pollution is a major concern for human health and the environment. Consequently, environmental standards have become stricter to improve air quality. Thanks to this, the ambient levels of O3 precursors such as VOCs and NOX have decreased. However, O3 levels in Europe, especially during winter, have increased, potentially impacting atmospheric o...

The detailed chemical characterization of gas and particle phase species is essential for interpreting the results of atmospheric simulation chamber experiments. Although the application of online techniques has advanced significantly over the last two decades, offline analytical methods such as GC–MS and LC–MS are still frequently used. In this ch...

A field campaign has been performed in the Madrid region to study the VOC influence in the growth of new particles in ambient air. A number of instruments have been deployed to characterize the main pollutant gases and particle properties and composition. The measurements were performed simultaneously at three sites (rural, urban background and urb...

Once pesticides are released into the environment, their active ingredient and other formulation compounds, such as coadjuvants or solvents, may undergo biological and chemical degradation, and form a range of products that could be even more hazardous than their precursors. These degradation products may also interact with the natural biogenic com...

Volatile organic compounds are a broad and important class of pollutants affecting the indoor air quality. They are emitted from commercial products, building materials, furniture, occupant activities and even occupants, etc., and can participate in the indoor chemistry reacting with oxidants or being formed from secondary reactions. Some VOCs are...

In early 2020, the COVID-19 pandemic spread globally, and severe measures to control it were implemented. This study investigates the impact of the lockdown on the air quality of three provinces in the Valencia region, eastern Spain, in the years 2015-2020, focusing on particulate matter (PM). A thorough statistical analysis using different approac...

This review emphasizes the importance of classification of surface reservoirs represented by building and indoor materials. Models developed in the past 45 years to study mainly non-reactive thermodynamic partitioning of air pollutants to surfaces as well as their validation through analytical measurements are discussed. Analytical techniques aimin...

Multi-oxygenated volatile organic compounds are important markers of air pollution and precursors of ozone and secondary aerosols in both polluted and remote environments. Herein, their accurate determination was enhanced. The approach was based on an automated system for active sampling and on-fibre derivatization coupled with the gas chromatograp...

This paper provides scientific results from a European LIFE project carried out in the Valencian region of Spain during the 2017 to 2018 time frame. In 2018, more than 60,000 tons of pesticides were commercialized in Spain, with approximately 15% destined for Valencian crops. In order to improve the air quality in the agricultural areas of this reg...

Photolysis is one the main drivers in atmospheric chemistry. Volatile organic compounds that bear one or more carbonyl functions can absorb UV light between 295 nm and 450 nm, enabling them to possibly photolyze in the atmosphere. Yet, very few data are available regarding the impact of such photolysis processes on the fate of multifunctional carbo...

Multi-oxygenated volatile organic compounds are important markers of air pollution and precursors of ozone and secondary aerosols in both polluted and remote environments. Herein, their accurate determination was enhanced. The approach was based on an automated system for active sampling and on-fiber derivatization coupled with GC-MS technique. The...

Criegee Intermediates (CI), formed in the ozonolysis of alkenes, play a central role in tropospheric chemistry as an important source of radicals, with stabilised CI (SCI) able to participate in bimolecular reactions, affecting climate through the formation of inorganic and organic aerosol. However, total SCI yields have only been determined for a...

The gas-phase atmospheric degradation of prosulfocarb (a widely used thiocarbamate herbicide in winter cereals) at different NOx concentrations was investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. Photolysis under sunlight conditions and reaction with ozone were shown as unimportant. The rate constant for the re...

The gas phase atmospheric degradation of pirimiphos-methyl (a widely used organophosphate insecticide and acaricide in many European regions) has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. Its photolysis has been studied under sunlight conditions and its reaction rate constant with OH radicals was mea...

Several experiments were performed in the European Photo-reactor - EUPHORE - for studying aerosol formation from organophosphorus pesticides such as diazinon, chlorpyrifos, chlorpyrifos-methyl and pirimiphos-methyl. The mass concentration yields obtained (Y) were in the range 5 - 44% for the photo-oxidation reactions in the presence and the absence...

The atmospheric particulate matter has a large impact on climate, biosphere behaviour and human health. Its study is complex because of large number of species are present at low concentrations and the continuous time evolution, being not easily separable from meteorology, and transport processes. Closed systems have been proposed by isolating spec...

Secondary organic aerosol (SOA) is well known to have adverse effects on air quality and human health. However, the dynamic mechanisms occurring during SOA formation and evolution are poorly understood. The time resolved SOA composition formed during the photo-oxidation of three aromatic compounds, methyl chavicol, toluene and 4-methyl catechol, we...

The phosphorothioate structure is highly present in several pesticides. However, there is a lack of information about its degradation process in air and the secondary pollutants formed. Herein, the atmospheric reactions of chlorpyrifos, one of the most world-used insecticide, and its main degradation product - chlorpyrifos-oxon - are described. The...

The α-dicarbonyl compounds glyoxal (CHOCHO) and methyl glyoxal (CH3C(O)CHO) are produced in the atmosphere by the oxidation of hydrocarbons and emitted directly from pyrogenic sources. Measurements of ambient concentrations inform about the rate of hydrocarbon oxidation, oxidative capacity, and secondary organic aerosol (SOA) formation. We present...

The phosphorothioate structure is highly present in several organophosphorus pesticides. However, there is insufficient information about its degradation process after the release to the atmosphere and the secondary pollutants formed. Herein, the atmospheric reaction of chlorpyrifos-methyl (o,o-dimethyl o-(3,5,6-trichloropyridin-2-yl) phosphorothio...

The OH initiated oxidation of chlorpyrifos (a widely used insecticide) and its photooxidation product chlorpyrifos- oxon were investigated at the large outdoor European Photoreactor (EUPHORE). The rate constants for reaction of chlorpyrifos and chlorpyrifos oxonwith OH radicals weremeasured using a conventional relative rate method. The value of th...

The α-dicarbonyl compounds glyoxal (CHOCHO) and methyl glyoxal (CH3C(O)CHO) are produced in the atmosphere by the oxidation of hydrocarbons, and emitted directly from pyrogenic sources. Measurements of ambient concentrations inform about the rate of hydrocarbon oxidation, oxidative capacity, and secondary organic aerosol (SOA) formation. We present...

With the aim of characterizing the main air pollutants (anthropogenic, biogenic and secondary reaction products) present in the Mediterranean coast of the Iberian Peninsula under different meteorological conditions (summer and winter) two field campaigns (February and June 2011) were performed in the context of the MODELISMOS project (Modelling and...

Within the MODELISMOS project (Modelling and analysis of mesometeorological processes on transport and accumulation of pollutants in the Western Mediterranean and their influence on chemical degradation mechanisms) two different campaigns, the first one in winter-(February 2012) and the second one in summer (September 2012), were carried out at the...

The gas-phase degradation of ethalfluralin, N-ethyl-α,α,α-trifluoro-N-(2-methylallyl)-2,6-dinitro-p-toluidine, a widely used herbicide, was investigated under atmospheric conditions at the large outdoor European simulation chamber (EUPHORE) in Valencia, Spain. The photolysis of ethalfluralin was investigated under solar radiation and the mean photo...

The oxidation of volatile organic compounds (VOCs) leads to formation of ozone and SOA, with consequences for air quality, health, crop yields, atmospheric chemistry and radiative transfer. Recent observations have identified Methyl Chavicol ("MC": Estragole; 1-allyl-4-methoxybenzene, C10H12O) as a major BVOC above pine forests in the USA, and oil...

Pollutants are emitted into the troposphere as a result of human activity and natural sources. Once emitted, these compounds undergo physical and chemical changes that result in the formation of other secondary pollutants that may be even more harmful than their predecessors. These transformations are strongly affected by the meteorological conditi...

Field measurements give on-site information about the state of the atmosphere under certain meteorological conditions on a specific time and location. But the atmosphere is a highly complicated reactive system on which many processes (transport, accumulation of pollutants, deposition, chemical reaction, etc) affected by weather conditions happen at...

The gas-phase degradation of propachlor (2-chloro-N-isopropylacetanilide), a widely used herbicide, was investigated under atmospheric conditions at the large outdoor European simulation chamber (EUPHORE) in Valencia, Spain. The rate coefficient for the reaction of hydroxyl radicals with propachlor was measured using a conventional relative rate te...

The gas phase atmospheric degradation of diazinon has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. The rate constant for reaction of diazinon with OH radicals was measured using a conventional relative rate method with di-n-buthylether as reference compound being k = (3.5 ± 1.2) × 10⁻¹¹ cm³ molecule⁻¹ s...

The gas-phase degradation of hymexazol (5-methylisoxazol-3-ol), a widely used fungicide, was investigated under atmospheric conditions at the European Photoreactor (EUPHORE) in Valencia, Spain, a large outdoor simulation chamber. The rate coefficient for the reaction of hydroxyl radicals with hymexazol was measured using a conventional relative rat...

The gas-phase atmospheric degradation of chlorpyrifos-methyl (a widely used organophosphate insecticide in Southern European regions) has been investigated at the large outdoor European Photoreactor (EUPHORE) in Valencia, Spain. Photolysis under sunlight conditions and reaction with ozone were shown to be unimportant. The rate constant for reaction...

An experimental investigation on the photolysis of the pesticide chloropicrin (trichloronitro methane CCl3NO2) under atmospheric conditions was carried out at the outdoor European Photoreactor (EUPHORE) in Valencia Spain The photodissociation rate coefficient J(obs)(CCl3NO2) was determined directly under sunlight conditions during spring and summer...

The atmospheric fate of pesticides can be studied at the large outdoor European simulation chamber (EUPHORE) in Valencia, Spain. The reactions that can be carried out at EUPHORE (European PHOtoREactor) include photolysis using natural sunlight, OH, NO 3 and ozone initiated oxidation reactions. The EUPHORE facility is up to the moment, one of the be...