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For a Positive Matrix Factorization (PMF) aerosol source apportionment (SA) studies there is no standard procedure to select the most appropriate chemical components to be included in the input dataset for a given site typology, nor specific recommendations in this direction. However, these choices are crucial for the final SA outputs not only in terms of number of sources identified but also, and consequently, in the source contributions estimates. In fact, PMF tends to reproduce most of PM mass measured independently and introduced as a total variable in the input data, regardless of the percentage of PM mass which has been chemically characterized, so that the lack of some specific source tracers (e.g. levoglucosan) can potentially affect the results of the whole source apportionment study. The present study elaborates further on the same concept, evaluating quantitatively the impact of lacking specific sources' tracers on the whole source apportionment, both in terms of identified sources and source contributions. This work aims to provide first recommendations on the most suitable and critical components to be included in PMF analyses in order to reduce PMF output uncertainty as much as possible, and better represent the most commons PM sources observed in many sites in Western countries. To this aim, we performed three sensitivity analyses on three different datasets across EU, including extended sets of organic tracers, in order to cover different types of urban conditions (Mediterranean, Continental, and Alpine), source types, and PM fractions. Our findings reveal that the vehicle exhaust source resulted to be less sensitive to the choice of analytes, although source contributions estimates can deviate significantly up to 44 %. On the other hand, for the detection of the non-exhaust one is clearly necessary to analyze specific inorganic elements. The choice of not analysing non-polar organics likely causes the loss of separation of exhaust and non-exhaust fa

The Geosciences for a Sustainable Planet network is an initiative reinforced by the recent integration of the Spanish Geological Survey (IGME) and the Oceanographic Spanish Institute (IEO) within the Spanish Scientific Research Council (CSIC). The network is aimed to provide Geosciences in Spain with a collaborative framework, to maximize synergies and address sustainability and future challenges with a planetary perspective. The network shares the strategic vision for the study and care of planet Earth as the only home available for our future, as embraced by many international organizations (e. g. the European Geosciences Union (EGU), United Nations Environment Programme (UNEP), International Union of Geological Sciences (IUGS), and the European Marine Board (EMB)). In Spain, Geosciences have played a fundamental role in properly assessing, managing, and seeking solutions for several natural and anthropogenic crises, e.g. the oil spill after the sinking of the Prestige petroleum vessel, the dumping of toxic mine sludge in Aznalcóllar, the eruption of the Cumbre Vieja volcano in La Palma island, the 2011 earthquake of Lorca, the environmental collapse of the Mar Menor oastal lagoon, or the decline in the groundwaters of Doñana National Park. Geoscientists have engaged as first responders with government agencies in emergency situations. Besides, geosciences is providing essential knowledge for public administration, as well as energy and mineral resources companies, water supply, contamination and waste elimination and reuse, and adaptation to geological and natural hazards. The network will enhance the capacity of the CSIC to respond to both, societal and public administration demands. Geosciences also provide the temporal and spatial scale to place current climate and environmental crises in the appropriate context. The network will implement outreach activities to illustrate the interactions of surface processes and biosphere with climatic fluctuations, atmosphe

During the COVID-19 pandemic, the use of face masks has been a worldwide primary protection measure to contain the spread of the virus. However, very little information is known about the possible inhalation of microplastics (MP) from wearing masks. This pilot study evaluates the presence of MP accumulated in nasal cavities through the nasal lavages technique. Six different commercial face masks were tested in 18 participants during five working days (8 h use/day). Eight different polymers (polystyrene, polyamide, poly(ethylene - propylene) diene monomer, polyester, polyethylene, polyvinylidene fluoride, polypropylene, and polyvinyl chloride) predominantly within the 20-300 µm size were detected in nasal lavages, with an average concentration of 28.3 ± 15.6 MP/5 mL nasal solution. Results demonstrate that MP in the nasal cavity are not associated to face mask use but rather to general exposure to airborne MP. We highlight the use of nasal lavages to evaluate human inhalation of MP and associate it to potential sources and risks.

Microplastics (MPs) are plastic particles (<5 mm) ubiquitous in water, soil, and air, indicating that humans can be exposed to MPs through ingestion of water and food, and inhalation.

Microplastics (MP) are plastic particles with dimension up to 5 mm. Due to their persistence, global spread across different ecosystems and potential human health effects, they have gained increasing attention during the last decade. However, the extent of human exposure to MP through different pathways and their intake have not been elucidated.

Black carbon (BC) is recognized as the most important warming agent among atmospheric aerosol particles. The absorption efficiency of pure BC is rather well-known, nevertheless the mixing of BC with other aerosol particles can enhance the BC light absorption efficiency, thus directly affecting Earth's radiative balance. The effects on climate of the BC absorption enhancement due to the mixing with these aerosols are not yet well constrained because these effects depend on the availability of material for mixing with BC, thus creating regional variations. Here we present the mass absorption cross-section (MAC) and absorption enhancement of BC particles (Eabs), at different wavelengths (from 370 to 880nm for online measurements and at 637nm for offline measurements) measured at two sites in the western Mediterranean, namely Barcelona (BCN; urban background) and Montseny (MSY; regional background). The Eabs values ranged between 1.24 and 1.51 at the urban station, depending on the season and wavelength used as well as on the pure BC MAC used as a reference. The largest contribution to Eabs was due to the internal mixing of BC particles with other aerosol compounds, on average between a 91% and a 100% at 370 and 880nm, respectively. Additionally, 14.5% and 4.6% of the total enhancement at the short ultraviolet (UV) wavelength (370nm) was due to externally mixed brown carbon (BrC) particles during the cold and the warm period, respectively. On average, at the MSY station, a higher Eabs value was observed (1.83 at 637nm) compared to BCN (1.37 at 637nm), which was associated with the higher fraction of organic aerosols (OA) available for BC coating at the regional station, as denoted by the higher organic carbon to elemental carbon (OC:EC) ratio observed at MSY compared to BCN. At both BCN and MSY, Eabs showed an exponential increase with the amount of non-refractory (NR) material available for coating (RNR-PM). The Eabs at 637nm at the MSY regional station reached values

Urban public buses worldwide carry hundreds of millions of passengers, all of whom inhale atmospheric pollutants in the form of particles and gases during what is commonly a daily commute. These urban journeys can provide a disproportionate percentage of the individual’s average daily exposure to inhalable contaminants, and recognition of this fact is reflected in a large body of scientific literature on air pollution and city transport that goes back over 50 years (e.g. Haagen-Smit, 1966; Fernández-Iriarte et al., 2020). The number of such publications has increased rapidly in recent years, accompanying the recognition of the damage to human health being inflicted by inhaling polluted urban air whilst travelling by road (e.g. Alameddine et al., 2016; Cepeda et al., 2017; Fruin et al., 2011; Hudda et al., 2011, 2012; Hudda and Fruin 2018; Jo and Yu, 2001; Leavey et al., 2017; Lee et al., 2015; Madl et al., 2015; Moreno et al., 2015, 2020; Tartakovsky et al., 2013; Xing et al., 2018; Yang et al., 2015; Zhu et al., 2007). A subset of publications dealing with air quality associated with transport microenvironments has included information specifically on buses and bus stops (e.g. Adams et al 2001; Asmi et al., 2009; Bel and Holst 2018; Chernyshev et al., 2018; Choi et al., 2018; Dales et al., 2007; Dons et a., 2012; Fernández- Iriarte 2020, 2021; Gajewski 2013; Hess et al., 2010; Li et al., 2009; Lim et al., 2015; Merritt et al., 2019; Moore et al., 2012; Moreno et al., 2015, 2020, 2021; Nogueira et al., 2019; Rivas et al., 2017; Schimek et al., 2001; Van Ryswyk et al., 2020; Velasco and Tan 2016; Wang et al., 2011). Most of these studies, whilst all providing valuable data, are based on relatively short sampling campaigns or models and commonly focused on a limited number of specific contaminants such as PM10 or PM2.5 mass, number concentrations of ultrafine particles (UFP), and/or levels of gaseous pollutants. The ambition of the Barcelona BUSAIR project was to prov

Measurements of CO2 and counting of occupants were carried out in 37 public bus trips during commuting rush hours in Barcelona (NE Spain) with the aim of evaluating parameters governing ventilation inside the vehicles and proposing actions to improve it. The results show that CO2 concentrations (1039 and 934 ± 386 ppm, as average and median, during rush hours but with average reduced occupancy due to the fair to be infected by SARS-CoV-2 during the measurement period, and measured in the middle of the busses) are in the lower range of values recorded in the literature for public buses, however an improvement in ventilation is required in a significant proportion of the journeys. Thus, we found better ventilation in the older Euro 3+ (retrofitted with filter traps and selective catalytic reduction) and Euro 5 buses (average 918 ± 257 ppm) than in the hermetically closed new Euro 6 ones (1111 ± 432 ppm). The opening of the windows in the older buses yielded higher ventilation rates (778 ± 432 ppm). The opening of all doors at all stops increases the ventilation by causing a fall in concentrations of 200-350 ppm below inter-stop concentrations, with this effect typically lasting 40-50 s in the hermetically closed new Euro 6 hybrid buses. Based on these results a number of recommendations are offered in order to improve ventilation, including measurement of CO2 and occupancy, and installation of ventilation fans on the top of the hermetically closed new buses, introducing outdoor air when a given concentration threshold is exceeded. In these cases, a CO2 sensor installed in the outdoor air intake is also recommended to take into account external CO2 contributions.

Environmental pollution from microplastics (MPs) in air is a matter of growing concern because of human health implications. Airborne MPs can be directly and continuously inhaled in air environments. Especially high MPs contributions can be found in indoor air due to the erosion and breakage of consumer, domestic and construction products, although there is little information available on their sources and concentrations and the risks they might pose. This is in part due to the fact that sampling and analysis of airborne MPs is a complex and multistep procedure where techniques used are not yet standardized. In this study, we provide an overview on the presence of MPs in indoor air, potential health impacts, the available methods for their sampling and detection and implications from the use of face masks during the COVID-19 pandemic.

This work evaluates the applicability of the reference protocol EUSAAR2 in the Semi-Continuous OCEC analyzer under two environments, an urban background site influenced by traffic emissions and a regional background site. The comparison of the 24-h averaged OC and EC measurements of the Semi-Continuous analyzer with the OC and EC concentrations determined offline in PM2.5 24 h filters yielded very good agreement for both denuded and undenuded samples. In the urban background site, the regression for EC yielded a slope of 0.93 and 1.04 (b = 0.07 and 0.05, R2 = 0.83 and 0.84), for denuded and undenuded samples respectively. The slopes of OC regressions were 0.99 (b = −0.18, R2 = 0.81) for the low volume and 0.93 (b = 0.12, R2 = 0.84) for the high volume samples. In the regional background site, the slopes of the EC regression with the denuded and undenuded samples was 0.91 and 1.02 correspondingly (b = 0 and − 0.03, R2 = 0.77 and 0.89). The regression of OC had slopes close to 1; 1.03 for the high volume and 0.95 for the low volume sampler (b = 0.08 and 0.26, R2 = 0.78 and 0.78). BC measurements obtained by an aethalometer and MAAP were in very good agreement with EC at both sampling sites. BC levels were consistently higher than EC (slope of the regression aethalometer BC vs EC slope a = 1.2, intercept b = 0.19, R2 = 0.79, for the urban background site and a = 1.9, b = −0.04, R2 = 0.94, for the regional site, slope MAAP BC vs EC a = 1.2, b = 0.06, R2 = 0.94, for the urban background site and 1.7, b = −0.03, R2 = 0.96, for the regional site). This confirms the need of using the site-specific mass absorption cross section (MAC) instead of the ones provided by manufacturers for the conversion of absorption units into BC mass concentration. BC data correlated very well with the optical EC obtained from the semi-continuous OCEC analyzer (a = 1.3, b = 0.16, R2 = 0.80 for the urban background site and a = 1.7, b = 0.009, R2 = 0.94 for the regional site, respectively). The c

Black carbon (BC) or elemental carbon (EC) is considered the second most important climate warming agent after CO2. BC is one of the components of ambient particulate matter (PM). The high absorption efficiency of BC is due to its electronic structure and composition that allows BC particles to absorb electromagnetic radiation over a wide range of wavelengths. The mass absorption crosssection (MAC) represents the efficiency that a BC particle has for absorbing light at a given wavelength and it is related to EC via eq. 1. Photochemical ageing of BC due to mixing with nonabsorbing (or less absorbing) particles, such as sulfate or organic aerosols, can increase the apparent MAC of BC above that of an uncoated BC particle.

While exposure to traffic pollutants significantly decreases with distance from the curb, very dense urban architectures hamper such dispersion. Moreover, the building height reduces significantly the dispersion of pollutants. We have investigated the horizontal variability of Black Carbon (BC) and the vertical variability of NO and BC within the urban blocks. Increasing the distance from road BC concentrations decreased following an exponential curve reaching halving distances at 25 m (median), although with a wide variability among sites. Street canyons showed sharper fall-offs than open roads or roads next to a park. Urban background concentrations were achieved at 67 m distance on average, with higher distances found for more trafficked roads. Vertical fall-off of BC was less pronounced than the horizontal one since pollutants homogenize quickly vertically after rush traffic hours. Even shallower vertical fall-offs were found for NO. For both pollutants, background concentrations were never reached within the building height. A street canyon effect was also found exacerbating concentrations at the lowest floors of the leeward side of the road. These inputs can be useful for assessing population exposure, air quality policies, urban planning and for models validation.

Introduction Desert dust concentrations raise concerns about adverse effects on human health. During the last decade, special attention has been given to mineral dust particles from desert dust and sand storms. However, evidence from previous reviews reported inconclusive results on their health effects and the biological mechanism remains unclear. We aim to systematically synthesise evidence on the health effects of desert dust and sand storms accounting for the relevant desert dust patterns from source areas and emissions, transport and composition. Methods an analysis We will conduct a systematic review that investigated the health effects of desert dust and sand storms in any population. The search will be performed for any eligible studies from previous reviews and selected electronic databases until 2018. Study selection and reporting will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data from individual studies will be extracted using a standardised data extraction form. Quality of the studies will be assessed using a risk of bias tool for environmental exposures developed by experts convened by the WHO. A meta-analysis will be performed by calculating the appropriate effect measures of association for binary and continuous outcomes from individual studies. Subgroup analyses will be performed by geographical areas to account for desert dust patterns. Ethics and dissemination No primary data will be collected. For this reason, no formal ethical approval is required. This systematic review will help to fill the research gaps in the knowledge of desert dust on human health. The results will be disseminated through a WHO peer-reviewed publication and a conference presentation. © 2019 Author(s) (or their employer(s)). Re-use permitted under CC BY. Published by BMJ.

We review the major features of desert dust outbreaks that are relevant to the assessment of dust impacts upon human health. Our ultimate goal is to provide scientific guidance for the acquisition of relevant population exposure information for epidemiological studies tackling the short and long term health effects of desert dust. We first describe the source regions and the typical levels of dust particles in regions close and far away from the source areas, along with their size, composition, and bio-aerosol load. We then describe the processes by which dust may become mixed with anthropogenic particulate matter (PM) and/or alter its load in receptor areas. Short term health effects are found during desert dust episodes in different regions of the world, but in a number of cases the results differ when it comes to associate the effects to the bulk PM, the desert dust-PM, or non-desert dust-PM. These differences are likely due to the different monitoring strategies applied in the epidemiological studies, and to the differences on atmospheric and emission (natural and anthropogenic) patterns of desert dust around the world. We finally propose methods to allow the discrimination of health effects by PM fraction during dust outbreaks, and a strategy to implement desert dust alert and monitoring systems for health studies and air quality management. © 2019 The Authors

Source apportionment of atmospheric PM1 is important for air quality control, especially in urban areas where high mass concentrations are often observed. Chemical analysis of molecular inorganic and organic tracer compounds and subsequently data analysis with receptor models give insight on the origin of the PM1 sources. In the present study, four source apportionment approaches were compared with an extended database containing inorganic and organic compounds that were measured during an intensive sampling campaign at urban traffic and urban background sites in Barcelona. Source apportionment of the combined database, containing both inorganic and organic compounds, was compared with more conventional approaches using inorganic and organic databases separately. Traffic emission sources were identified in all models for the two sites. The combined inorganic and organic databases provided higher discrimination capacity of emission sources. It identified aerosols generated by regional recirculation of biomass burning, secondary biogenic organic aerosols, harbor emissions, and specific industrial emissions. In this respect, this approach identified a relevant industrial source situated at NE Barcelona in which a waste incinerator plant, a combined-cycle power plant, and an industrial glass complex are located. Models using both inorganic and organic molecular tracer compounds improve the source apportionment of urban PM