Alexandre Caseiro

Research Institute for Sustainability (RIFS)

The use of low-cost sensors (LCS) for the evaluation of the ambient pollution by particulate matter (PM) has grown and become significant for the scientific community in the past few years. However promising this novel technology is, the characterization of their limitations is still not satisfactory. Reports in the scientific literature rely on ca...

Local policies are part of the toolbox available to decision makers to improve air quality but their effectiveness is underevaluated and underreported. We evaluate the impact of the pedestrianization of a street in the city centre of Berlin on the local air pollution. Nitrogen dioxide (NO2) was measured on the street where the policy was implemente...

Gas flaring is an environmental problem of local, regional and global concerns. Gas flares emit pollutants and greenhouse gases, yet knowledge about the source strength is limited due to disparate reporting approaches in different geographies, whenever and wherever those are considered. Remote sensing has bridged the gap but uncertainties remain. T...

Low-cost particulate matter systems output airborne particle mass concentrations based on optical particle counter sensors. Because the relationship between the particle number and mass is complex and varies with time and space, the research community has developed correction methodologies which imply co-locating a low-cost system and a reference-g...

Mobility behavior changes due to the COVID-19 pandemic have opened a window of opportunity for an accelerated transition towards sustainable mobility. Many European cities installed temporary cycling infrastructure which can be considered a niche innovation in the Multi-Level-Perspective of transitions (Geels, 2002). We empirically assess the effec...

Background The SARS-CoV-2 virus has been spreading in Germany since January 2020, with regional differences in incidence, morbidity, and mortality. Long-term exposure to air pollutants as nitrogen dioxide (NO2), nitrogen monoxide (NO), ozone (O3), and particulate matter (<10 μm PM10, <2.5 μm PM2.5) has a negative impact on respiratory functions. We...

Background: The SARS-CoV-2 virus has been spreading in Germany since January 2020, with regional differences in incidence, morbidity, and mortality. Long-term exposure to air pollutants as nitrogen dioxide (NO2), nitrogen monoxide (NO), ozone (O3), and particulate matter (<10µm PM10, < 2.5µm PM2.5,) has a negative impact on respiratory functions. W...

Background: The SARS-CoV-2 virus has been spreading in Germany since January 2020, with regional differences in incidence, morbidity, and mortality. Long-term exposure to air pollutants as nitrogen dioxide (NO2), nitrogen monoxide (NO), ozone (O3), and particulate matter (<10µm PM10, < 2.5µm PM2.5,) has a negative impact on respiratory functions. W...

The last 2 decades have seen substantial technological advances in the development of low-cost air pollution instruments using small sensors. While their use continues to spread across the field of atmospheric chemistry, the air quality monitoring community, and for commercial and private use, challenges remain in ensuring data quality and comparab...

Exposure to poor air quality is considered a major influence on the occurrence of cardiovascular and respiratory diseases. Air pollution has also been linked to the severity of the effects of epidemics such as COVID-19 caused by the SARS-CoV-2 virus. Epidemiological studies require datasets of the long-term exposure to air pollution. We present the...

Cities in the 21st century are dynamically changing in response to environmental and societal pressures, not least among which are climate change and air pollution. In some of these metropoles, such as Berlin, a transformation of mobility systems has already begun. Along a mid-sized street in Berlin, a measurement campaign was conducted in 2020 to...

Urban air pollution is a substantial threat to human health. Traffic emissions remain a large contributor to air pollution in urban areas. The mobility restrictions put in place in response to the COVID-19 pandemic provided a large-scale real-world experiment that allows for the evaluation of changes in traffic emissions and the corresponding chang...

The last two decades have seen substantial technological advances in the development of low-cost air pollution instruments using small sensors. While their use continues to spread across the field of atmospheric chemistry, the air quality monitoring community, as well as for commercial and private use, challenges remain in ensuring data quality and...

Gas flares are a regionally and globally significant source of atmospheric pollutants. They can be detected by satellite remote sensing. We calculate the global flared gas volume and black carbon emissions in 2017 by applying (1) a previously developed hot spot detection and characterisation algorithm to all observations of the Sea and Land Surface...

This article represents the current state of the art in analyzing gas flaring (GF) from space. GF is a prominent source of air pollution, with significant global and local impacts. Its emissions contribute to climate change and air pollution, and its practice is a waste of a valuable energy source. A key barrier in evaluating the status of this phe...

Gas flares are a regionally and globally significant source of atmospheric pollutants. They can be detected by satellite remote sensing. We calculate the global flared gas volume and black carbon emissions in 2017 by (1) applying a previously developed hot spot detection and characterisation algorithm to all observations of the Sea and Land Surface...

Gas flaring is a disposal process widely used in the oil extraction and processing industry. It consists in the burning of unwanted gas at the tip of a stack and due to its thermal characteristic and the thermal emission it is possible to observe and to quantify it from space. Spaceborne observations allows us to collect information across regions...

Gas flaring is a disposal process widely used in the oil extraction and processing industry. It consists in the burning of unwanted gas at the tip of a stack and due to its thermal characteristic and the thermal emission it is possible to observe and to quantify it from space. Spaceborne observations allows us to collect information across regions...

Gas flaring is a disposal process widely used in the oil extraction and processing industry. It consists in the burning of unwanted gas at the tip of a stack. We have successfully adapted the VIIRS Nightfire algorithm for the detection and characterisation of gas flares to SLSTR observations on-board the Sentinel-3 satellites. A hot event at temper...

Gas flaring (GF) consists in the burning of unwanted gas at the tip of a stack. It is widely used as a disposal process in the oil extraction and processing industry. We successfully adapted the VIIRS Nightfire algorithm for the detection and characterisation of gas flares at night for the SLSTR instrument on-board the Sentinel-3 satellites. The m...

The chemical composition of size-segregated particulate matter (PM) was studied during summer and winter sampling campaigns, at two different urban sites (roadside and urban background) in the city of Madrid, Spain. PM was sampled with high volume cascade impactors, in 4 size ranges: 10–2.5, 2.5–1, 1–0.5 and < 0.5 μm. The carbonaceous content (OC a...

An atmospheric aerosol study was performed in 2008 inside an urban road tunnel, in Lisbon, Portugal. Using a high volume impactor, the aerosol was collected into four size fractions (PM0.5, PM0.5–1, PM1–2.5 and PM2.5–10) and analysed for particle mass (PM), organic and elemental carbon (OC and EC), polycyclic aromatic hydrocarbons (PAH), soluble in...

Lisbon is the largest urban area in the Western European coast. Due to this geographical position the Atlantic Ocean serves as an important source of particles and plays an important role in many atmospheric processes. The main objectives of this study were to (1) perform a chemical characterization of particulate matter (PM2.5) sampled in Lisbon,...

The particulate emissions from biomass burning are a growing concern due to the recent evidence of their ubiquitous and important contribution to the ambient aerosol load. A possible strategy to apportion the biomass burning share of particulate matter is the use of organic molecular tracers. Anhydrosugars (levoglucosan, mannosan and galactosan), t...

One Plus Sequential Air Sampler—Partisol was placed in a small village (Foros de Arrão) in central Portugal to collect PM10 (particles with an aerodynamic diameter below 10μm), during the winter period for 3months (December 2009–March 2010). Particles masses were gravimetrically determined and the filters were analyzed by instrumental neutron activ...

The archipelago of Cape Verde is located on the eastern North Atlantic, about 500 km west of the African coast. Its geographical location, inside the main area of dust transport over tropical Atlantic and near the coast of Africa, is strongly affected by mineral dust from the Sahara and the Sahel regions. In the scope of the CVDust project a surfac...

In summer 2009, emissions of trace gases and aerosols from several wildfires occurring in Portugal were sampled. A portable high-volume sampler was used to collect sequentially, on quartz fibre filters, coarse (PM(2.5-10)) and fine (PM(2.5)) smoke particles. Tedlar air sampling bags have been used for complementary chemical characterisation of the...

A series of source tests was performed to evaluate the chemical composition of particle emissions from the woodstove combustion of four prevalent Portuguese species of woods: Pinus pinaster (maritime pine), Eucalyptus globulus (eucalyptus), Quercus suber (cork oak) and Acacia longifolia (golden wattle). Analyses included water-soluble ions, metals,...

At urban areas in south Europe atmospheric aerosol levels are frequently above legislation limits as a result of road traffic and favourable climatic conditions for photochemical formation and dust suspension. Strategies for urban particulate pollution control have to take into account specific regional characteristics and need correct information...

Gaseous and particulate samples from the smoke from prescribed burnings of a shrub-dominated forest with some pine trees in Lousã Mountain, Portugal, in May 2008, have been collected. From the gas phase Fourier transform infrared (FTIR) measurements, an average modified combustion efficiency of 0.99 was obtained, suggesting a very strong predominan...

Lisbon is the capital city of Portugal with about 565,000 residents and a population density of 6,600 inhabitants per square kilometre. The town is surrounded by satellite cities, forming together a region known as "Lisbon Metropolitan Area" with about 3 million inhabitants. It is estimated that more than one million citizens come into the Lisbon a...

Particulate matter, either with aerodynamical diameter below 10 mum (PM10) or the fine (aerodynamical diameter below 2.5 mum, PM2.5) or coarse (aerodynamical diameter between 2.5 and 10 mum, PM2.5-10) modes only, are presently regarded as one of the main threats to public health instigated by air pollution. The levels of ambient air particulates ar...

An apartment bedroom located in a residential area of Aveiro (Portugal) was selected with the aim of characterizing the cellulose content of indoor aerosol particles. Two sets of samples were taken: (1) PM10 collected simultaneously in indoor and outdoor air; (2) PM10 and PM2.5 collected simultaneously in indoor air. The aerosol particles were conc...

The number of children reporting rhinitis by month is compared with air pollutant concentrations in Lisbon, where they live and attend school. INAA, ionic exchange chromatography and data accessed through the internet were statistically processed with the children rhinitis data. Association between rhinitis and atmospheric variables are processed u...

In 2006, elementary schools of inner-city Lisbon, Portugal were given questionnaires to identify respiratory problems. In 1,175 children aged 5–10years, 27.7% reported rhinitis, 2.5% reported hay fever and 25.9% reported asthma symptoms. April and August were the months with higher incidence of rhinitis, with a considerable difference nonetheless (...

The goal of this research is to determine trends and sources of airborne particulates in the centre of Lisbon, by using speciated particulate-matter data and back-trajectory analyses. Results showed that, in 2007, the annual PM(2.5) concentration exceeded the World Health Organization recommended levels. PM(2.5) diurnal variability and the ratio be...

Recent health studies evidence that epidemiological studies must be combined with accurate analyses of the physico-chemical properties of the particles in order to determine the effects of atmospheric aerosols on human health. The project "Atmospheric Aerosol Impacts on Human Health" focuses on the chemical characterization of PM2.5 aerosols with t...

Anhydrosugars (levoglucosan, mannosan and galactosan) were investigated during one year in three Austrian regions at three types of sites (city-heavy traffic-impacted, city-residential and background) in order to assess the magnitude of the contribution of wood smoke to the particulate matter load and its organic fraction. The annually averaged con...

Atmospheric concentration measurements of tracers for primary biological aerosol particles (PBAPs) have been used to obtain estimates of their release into the atmosphere. Emission flux data of surrogate compounds, for which concurrent concentration measurements were available, were used to quantify the release of PBAPs as PM10 mass. Results indica...

Until about a decade ago, black carbon (BC) was thought to be the only light absorbing substance in the atmospheric aerosol except for soil or desert dust In more recent years, light absorbing polymeric carbonaceous material was found in atmospheric aerosols. Absorption increases appreciably toward short wavelengths, so this fraction was called bro...

In Portugal, during summer 2003, unusually large forested areas (>300,000 ha) were destroyed by fire, emitting pollutants to the atmosphere. During this period, aerosol samples were collected in the Aveiro region, and analysed for total mass and a set of inorganic and organic compounds, including tracers of biomass burning. Comparisons of aerosol s...

For recent campaigns we will compare and discuss different methods to apportion wood burning in particulate matter. These methods will include aerosol mass spectrometry, carbon 14 analyses, levoglucosan, and multi-wavelength aethalometer data.

Residential wood combustion has only recently been recognized as a major contributor to air pollution in Switzerland and in other European countries. A source apportionment method using the aethalometer light absorption parameters was applied to five winter campaigns at three sites in Switzerland: a village with high wood combustion activity in win...

Temporal and spatial trends of particulate n-alkanes C24–C33 have been investigated at urban-fringe and traffic exposed inner urban sites of a larger European city. The annual average sum of n-alkanes at the four sampling sites ranged from 21 to 31ngm−3. The urban impact factor was ∼30% averaged over the year. The seasonal biogenic emissions of the...

Real-time measurements of submicrometer aerosol were performed using an Aerodyne aerosol mass spectrometer (AMS) during three weeks at an urban background site in Zurich (Switzerland) in January 2006. A hybrid receptor model which incorporates a priori known source composition was applied to the AMS highly time-resolved organic aerosol mass spectra...

Woodsmoke samples derived from the combustion of beech, oak, spruce, larch and softwood briquettes in a closed stove have been collected and analysed so as to derive chemical profiles for ambient particulate matter (PM) source apportionment studies, for example, by CMB modelling. Trace metals, soluble ions, carbon species total carbon (TC), element...

In this work, we apply the CMB model to a set of samples collected in Vienna. Those samples were chemically characterised for a wide range of chemical species as were samples from aerosol sources. The set of samples represent periods in which the threshold value of the PM10 level was exceeded, thus providing an insight over the causes of such episo...

Die Beprobung für das Projekt AQUELLA – Kärnten/Klagenfurt erfolgte von Oktober 2004 bis Juli 2005. In den Proben wurden Ruß (EC), organischer Kohlenstoff (OC), Ionen, Spurenmetalle, ausgewählte polare und apolare Verbindungen, sowie als organische Makrokomponenten Levoglucosan, Cellulose und „humic like substances“ (HULIS) analysiert. Die Quellenp...

An improved method is described for the quantification of primary sugars, sugar alcohols and anhydrosugars in atmospheric aerosols, making use of separation by high-performance anion-exchange chromatography (HPAEC) with pulsed amperometric detection (PAD). Quartz fibre filters from high-volume samplers were extracted with water and the extract inje...

Atmospheric levoglucosan has been determined as a proxy for '' biomass smoke '' in samples from six background stations on a west - east transect extending from the Atlantic ( Azores) to the mid- European background site KPZ ( K- Puszta, Hungary). Concentration levels of levoglucosan ( biannual averages) in the west - east transect range from 0.005...

On the basis of a 2-year comprehensive data set obtained within the CARBOSOL project, seasonal source apportionment of PM2.5 aerosol is attempted for five rural/remote sites in Europe. The approach developed combines radiocarbon measurements with bulk measurements of organic carbon (OC), elemental carbon (EC), and two organic tracers ( levoglucosan...

1] In the framework of the European CARBOSOL project (Present and Retrospective State of Organic versus Inorganic Aerosol over Europe: Implications for Climate), atmospheric aerosol was continuously sampled for 2 years at six sites along a west-east transect extending from Azores, in the mid-Atlantic Ocean, to K-Puszta (Hungary), in central Europe....

1] In this paper the European Monitoring and Evaluation Programme (EMEP) MSC-W model is used to assess our understanding of the sources of carbonaceous aerosol in Europe (organic carbon (OC), elemental carbon (EC), or their sum, total carbon (TC)). The modeling work makes use of new data from two extensive measurement campaigns in Europe, those of...

Bis 2004 galt in Österreich als gesetzlich zu erfassende Staubfraktion Gesamtschwebestaub oder auch abgekürzt TSP (für „total suspended particles“). Da feinere Teilchen tiefer in den Atemtrakt gelangen und in epidemiologischen Untersuchungen auch eine höhere Wirkung auf Atemtrakt- und Herz-Kreislauferkrankungen aufzeigen, wurden in den USA bereits...

Ambient samples of fine organic aerosol collected from a rural area (Moitinhos) in the vicinity of the small coastal Portuguese city of Aveiro over a period of more than one year have been solvent-extracted and quantitatively characterised by gas chromatography–mass spectrometry. Particles were also analysed with a thermal-optical technique in orde...

The summer of 2003 was characterized by an intense heat wave across Europe that resulted in a large number of deaths and intense and extended forest fires. In Portugal, during this period more than 300000 ha of forests were destroyed by fire, during a short period, emitting enormous quantities of pollutants to the atmosphere. These emissions have p...

Efectuaram-se campanhas de medição de poluentes na cidade do Porto (uma de Inverno e outra de Verão) em dois locais, um situado junto a uma via de tráfego intenso e outro cerca de 500 m afastado das principais vias de tráfego, reflectindo um " fundo urbano ". Em ambos os locais monitorizaram-se em contínuo CO, O3 , NOx e PM10 (monitor β). Também se...