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Abstract: Mineral dust is an important aerosol species in the Earth’s atmosphere and has a major source within North Africa, of which the Sahara forms the major part. Aerosol Time of Flight Mass Spectrometry (ATOFMS) is first used to determine the mixing state of dust particles collected from the land surface in the Saharan region, showing low abundance of species such as nitrate and sulphate internally mixed with the dust mineral matrix. These data are then compared with the ATOFMS single particle mass spectra of Saharan dust particles detected in the marine atmosphere in the vicinity of the Cape Verde islands, which are further compared with those from particles with longer atmospheric residence sampled at a coastal station at Mace Head, Ireland. Saharan dust particles collected near the Cape Verde Islands showed increased internally mixed nitrate but no sulphate, whilst Saharan dust particles collected on the coast of Ireland showed a very high degree of internally mixed secondary species including nitrate, sulphate and methanesulphonate. This uptake of secondary species will change the pH and hygroscopic properties of the aerosol dust and thus can influence the budgets of other reactive gases, as well as influencing the radiative properties of the particles and the availability of metals for dissolution. [Copyright &y& Elsevier]

Abstract: Samples of particulate matter were collected during the period from October 2006 through September 2007 in a rural station located 12 km from the city of Colima. A total of 3600 particles were analyzed by SEM-EDS and then classified by their chemical composition and morphology in order of abundance: those rich in C, Fe, Si–Al, Cl–Na, Ca, Ba; and to a lesser abundance, particles rich in heavy metals such as Pb and V–Ni were observed. A factorial analysis was carried out to determine the main elements related with the emission sources such as crustal/farming; fuel-oil; marine; volcanic activity and industry. Trough the seasons, the dominant winds causes the presence of anthropogenic particles in the rural site. The information presented in this study aims to give insight and detailed of the analysis of the morphological characteristics and chemical composition of atmospheric particles at individual level in a rural site from Colima State, Mexico. [Copyright &y& Elsevier]

Abstract: For more than two decades a number of frameworks for scientific knowledge production are being proposed by science and technology researchers. They all advocate an extended involvement of non-specialists, in particular when it comes to knowledge production applicable to practical societal problems. We look to what extent these new frameworks have taken ground within a particular research community: the ACCENT Network of Excellence which coordinates European atmospheric chemistry and physics research applicable to air pollution and climate change. We did so by stimulating a debate through a “blog”, a survey and in-depth interviews with ACCENT scientists about the interaction between science, policy making and civil society, to which a great deal of ACCENT member contributed in writing or verbally. Most of them had interactions with policy makers and/or the general public, and they generally believe that interactions with spheres other than the scientific are needed. While such interactions give personal insight and satisfaction, they seem to have little impact on the goals and the practice of the scientific work itself. Extended frameworks of science production that go beyond the disciplinary mode seem to emerge at the level of individual scientists, yet they still need to find their way to the level of scientific project management. In this paper we discuss the justifications and barriers to implement a higher degree of extended knowledge integration in applied science projects such as ACCENT. It is felt that the community of atmospheric chemists and physicists is mature for such an implementation and recommendations are given to help and make this happen. [Copyright &y& Elsevier]

• Associations between sources of particle number concentrations and daily deaths. • Time series analysis was carried out for Barcelona, Helsinki, London and Zurich. • Daily photonucleation, fresh traffic, urban, and secondary source contributions. • Inconsistent associations across cities, sources and lags. • Risk increases were stronger for respiratory than for cardiovascular daily mortality. The evidence on the association between ultrafine (UFP) particles and mortality is still inconsistent. Moreover, health effects of specific UFP sources have not been explored. We assessed the impact of UFP sources on daily mortality in Barcelona, Helsinki, London, and Zurich. UFP sources were previously identified and quantified for the four cities: daily contributions of photonucleation, two traffic sources (fresh traffic and urban, with size mode around 30 nm and 70 nm, respectively), and secondary aerosols were obtained from data from an urban background station. Different periods were investigated in each city: Barcelona 2013–2016, Helsinki 2009–2016, London 2010–2016, and Zurich 2011–2014. The associations between total particle number concentrations (PNC) and UFP sources and daily (natural, cardiovascular [CVD], and respiratory) mortality were investigated using city-specific generalized linear models (GLM) with quasi-Poisson regression. We found inconsistent results across cities, sources, and lags for associations with natural, CVD, and respiratory mortality. Increased risk was observed for total PNC and natural mortality in Helsinki (lag 2; 1.3% [0.07%, 2.5%]), CVD mortality in Barcelona (lag 1; 3.7% [0.17%, 7.4%]) and Zurich (lag 0; 3.8% [0.31%, 7.4%]), and respiratory mortality in London (lag 3; 2.6% [0.84%, 4.45%]) and Zurich (lag 1; 9.4% [1.0%, 17.9%]). A similar pattern of associations between health outcomes and total PNC was followed by the fresh traffic source, for which we also found the same associations and lags as for total PNC. The urban source (mostly aged traffic) was associated with respiratory mortality in Zurich (lag 1; 12.5% [1.7%, 24.2%]) and London (lag 3; 2.4% [0.90%, 4.0%]) while the secondary source was associated with respiratory mortality in Zurich (lag 1: 12.0% [0.63%, 24.5%]) and Helsinki (4.7% [0.11%, 9.5%]). Reduced risk for the photonucleation source was observed for respiratory mortality in Barcelona (lag 2, −8.6% [−14.5%, −2.4%]) and for CVD mortality in Helsinki, as this source is present only in clean atmospheres (lag 1, −1.48 [−2.75, −0.21]). We found inconsistent results across cities, sources and lags for associations with natural, CVD, and respiratory mortality. [ABSTRACT FROM AUTHOR]

The physical characterisation of metrics representative of ambient air particle concentration is becoming a topic of great interest for urban air quality monitoring and human exposure assessment. In this article, the influence of sea breeze circulation and primary road traffic emissions on the relationship between the urban aerosol number (N3, particles >3nm), black carbon <10μm (BC), PM1, PM2.5, PM2.5–10 (PMx) concentrations was studied in a coastal city (Santa Cruz de Tenerife, Canary Islands). The daily cycles of sea and mountain breezes (inland during daylight and seaward at night) and road traffic emissions exerted a great, and well differentiated, influence on the BC, N3 and PMx concentrations. In this scenario, the following major aerosol features were observed: (1) fresh vehicle exhaust emissions resulted in high BC and N3 concentrations, in such a way that these two metrics increased when the “road traffic intensity (vehiclesh−1)/wind speed” ratio increased, (2) PM1 and PM2.5 levels were lower during daylight (due to inland entry of relatively clean marine air masses) than at night (due to the seaward drainage airflow resulting in the transport of aged particulate pollutants from the city), (3) although N3 and BC concentrations exhibited a significant correlation during the whole study period, the N3/BC ratio experienced a daily evolution with a maximum during daylight. Thus, high N3 concentrations associated with high N3/BC ratios and high solar irradiance conditions were recorded during the daylight inland breeze period due to an enhancement of processes favouring new particle formation. Data analysis points out that this enhancement in the new particle formation processes is strongly related to the nucleation of photo-oxidized vapours under the relatively low PMx (and consequently low aerosol surface area) concentrations prompted by the inland entry of clean marine air due to the daylight breeze blowing. The results obtained show that, in addition to the vehicle exhaust emissions, new particle formation in coastal urban areas due to photo-oxidation processes may significantly contribute to the ultrafine particle concentration. [Copyright &y& Elsevier]

Abstract: The (co)-firing of low-cost alternative fuels is expected to increase in the forthcoming years in the EU because of the economic and environmental benefits provided by this technology. This study deals with the impact of the different coal/waste fuel ratio of the feed blend on the mineralogy, the chemical composition and especially on the leaching properties of fly ash. Different blends of coal, petroleum coke, sewage sludge, wood pellets, coal tailings and other minor biomass fuels were tested in PCC (pulverised coal combustion) and FBC (fluidized bed combustion) power plants. The co-firing of the studied blends did not drastically modify the mineralogy, bulk composition or the overall leaching of the fly ash obtained. This suggests that the co-firing process using the alternative fuels studied does not entail significant limitations in the re-use or management strategies of fly ash. [Copyright &y& Elsevier]

Outdoor levels of fine particles (PM2. 5; particles <2. 5μm) have been associated with cardiovascular health. Persons with existing cardiovascular disease have been suggested to be especially vulnerable. It is unclear, how well outdoor concentrations of PM2. 5 and its constituents measured at a central site reflect personal exposures in Southern European countries. The objective of the study was to assess the relationship between outdoor and personal concentrations of PM2. 5, absorbance and sulphur among post-myocardial infarction patients in Barcelona, Spain. Thirty-eight subjects carried personal PM2. 5 monitors for 24-h once a month (2–6 repeated measurements) between November 2003 and June 2004. PM2. 5 was measured also at a central outdoor monitoring site. Light absorbance (a proxy for elemental carbon) and sulphur content of filter samples were determined as markers of combustion originating and long-range transported PM2. 5, respectively. There were 110, 162 and 88 measurements of PM2. 5, absorbance and sulphur, respectively. Levels of outdoor PM2. 5 (median 17μgm3) were lower than personal PM2. 5 even after excluding days with exposure to environmental tobacco smoke (ETS) (median after exclusion 27μgm3). However, outdoor concentrations of absorbance and sulphur were similar to personal concentrations after exclusion of ETS. When repeated measurements were taken into account, there was a statistically significant association between personal and outdoor absorbance when adjusting for ETS (slope 0. 66, p<0. 001), but for PM2. 5 the association was weaker (slope 0. 51, p=0. 066). Adjustment for ETS had little effect on the respective association of S (slope 0. 69, p<0. 001). Our results suggest that outdoor measurements of absorbance and sulphur can be used to estimate both the daily variation and levels of personal exposures also in Southern European countries, especially when exposure to ETS has been taken into account. For PM2. 5, indoor sources need to be carefully considered. [Copyright &y& Elsevier]

Abstract: An arsenic speciation study has been performed in PM10 samples collected on a fortnight basis in the city of Huelva (SW Spain) during 2001 and 2002. The arsenic species were extracted from the PM10 filters using a NH2OH·HCl solution and sonication, and determined by HPLC–HG–AFS. The mean bulk As concentration of the samples analyzed during 2001 and 2002 slightly exceed the mean annual 6ngm−3 target value proposed by the European Commission for 2013, arsenate [As(V)] being responsible for the high level of arsenic. The speciation analyses showed that As(V) was the main arsenic species found, followed by arsenite [As(III)] (mean 6.5 and 7.8ngm−3 for As(V), mean 1.2 and 2.1ngm−3 for As(III), in 2001 and 2002, respectively). The high levels of arsenic species found in PM10 in Huelva have a predominant industrial origin, such as the one from a nearby copper smelter, and do not present a seasonal pattern. The highest daily levels of arsenic species correspond to synoptic conditions in which the winds with S and SW components transport the contaminants from the main emission source. The frequent African dust outbreaks over Huelva may result in an increment of mass levels of PM10, but do not represent a significant input of arsenic in comparison to the anthropogenic source. The rural background levels of arsenic around Huelva are rather high, in comparison to other rural or urban areas in Spain, showing a relatively high atmosphere residence time of arsenic. This work shows the importance of arsenic speciation in studies of aerosol chemistry, due to the presence of arsenic species [As(III) and As(V)] with distinct toxicity. [Copyright &y& Elsevier]

Abstract: In this study, the application of some zeolitised fly ashes and synthetic zeolites to the decontamination of the leachate produced in a municipal solid waste (MSW) treatment plant and to the liquid waste from a pig farm was analyzed. Thus, the reduction of organic matter (BOD and COD), ammonium and total nitrogen, phosphorus and metals contents after a zeolite treatment was evaluated. Several synthetic zeolites were tested: some commercial zeolites and other synthetic zeolites and zeolitised ashes obtained after a coal fly ash alkaline hydrothermal process. Two forms of contact between the zeolitic material and the liquid waste were tested: in a stirred tank and in a column. In addition, other variables determined were the amount of zeolite and the residence time. The results showed that zeolites, especially zeolitised fly ash, clearly produced a strong reduction in the leachate nitrogen and phosphorus content. [Copyright &y& Elsevier]

This paper synthesizes data on aerosol (or particulate matter, PM) chemical characteristics, which were obtained in European aerosol research activities at natural, rural, near-city, urban, and kerbside sites over the past decade. It includes only two (nearby) sites in the semi-arid Mediterranean area, and lacks data from Eastern Europe. PM chemical compositions are compared with the PM mass concentrations in PM10, PM2.5, and further size resolved PM fractions (chemical mass closure). Such data sets are more comprehensive than those currently provided by air quality monitoring networks (e.g. EMEP, EUROAIRNET). Data available from 24 sites in Europe were reviewed. They were processed and plotted to allow comparisons in spite of differences in the sampling and analytical techniques used in various studies. A number of conclusions are drawn among which are the following.Organic matter appears to be the major component of PM10 and PM2.5, except at natural and rural background sites, where sulphate contribution may be larger. Mineral dust shows up as a major component of PM10 at kerbside sites. Black carbon contributes 5–10% to PM2.5 and somewhat less to PM10 at all sites, including the natural background sites. Its contribution seems higher (15–20%) at some of the kerbside sites, but these data may be affected by analytical artefacts. On days when PM10 >50 μg m−3, nitrate concentrations can overtake organic matter concentrations in PM10 and PM2.5. High PM concentration episodes are often observed in cold periods, when the pollutant dispersion is least. Measurements indicate that the condensation in the particle phase of semi-volatile species like nitrate and (unspecified) organics is also favoured by cold temperatures. In particles with a diameter <150 nm (i.e., most atmospheric particles), organic matter and black carbon are by far the major components.More data are known to be available within the scientific community, which could enrich the present data set and strengthen the conclusions made above. Most of them are not made available yet. The investment in new approaches, which would bridge the technological gap between scientific measurements and regulatory monitoring networks, is strongly needed. [Copyright &y& Elsevier]

This paper synthesizes data on aerosol (particulate matter, PM) physical characteristics, which were obtained in European aerosol research activities at free-troposphere, natural, rural, near-city, urban, and kerbside sites over the past decade. It covers only two sites in the semi-arid Mediterranean area, and lacks data from Eastern Europe. The data include PM10 and/or PM2.5 mass concentrations, and aerosol particle size distributions. Such data sets are more comprehensive than those currently provided by air quality monitoring networks (e.g. EMEP, EUROAIRNET). Data available from 31 sites in Europe (called “The Network”) were reviewed. They were processed and plotted to allow comparisons in spite of differences in the sampling and analytical techniques used in various studies. A number of conclusions are drawn as follows:Background annual average PM10 and PM2.5 mass concentrations for continental Europe are 7.0±4.1 and 4.8±2.4 μg m−3, respectively.The EU 2005 annual average PM10 standard of 40 μg m−3 is exceeded at a few sites in The Network. At all near city, urban and kerbside sites, the EU 2010 annual average PM10 standard of 20 μg m−3, as well as the US-EPA annual average PM2.5 standard of 15 μg m−3 are exceeded. In certain regions, PM10 and PM2.5 in cities are strongly affected by the regional aerosol background.There is no “universal” (i.e. valid for all sites) ratio between PM2.5 and PM10 mass concentrations, although fairly constant ratios do exist at individual sites. There is no universal correlation between PM mass concentration on the one hand, and total particle number concentration on the other hand, although a ‘baseline’ ratio between number and mass is found for sites not affected by local emissions. This paper is the first part of two companion papers of which the second part describes chemical characteristics. [Copyright &y& Elsevier]

A source apportionment study was performed to characterise PM10 sources in the urban area of Madrid. Receptor modelling techniques were applied to obtain the different source contributions, identifying four main sources that contribute to most of the analysed PM10 mass, namely: road traffic, crustal/mineral, secondary and marine aerosol. PM10 mean concentration and chemical profile were obtained for each source category by multilinear regression analysis. Road traffic was found to be the major contributor to the PM10 mass (48%), together with crustal (26%) and secondary particles (18%). A minor contribution has been associated to marine aerosol (3%), while 5% of the PM10 mass has been attributed to non-identified sources. An analysis of the geographical origin was performed for remote sources. Residence time probability values were calculated based on air mass back trajectories information. Different elements have been selected as tracers of the sources. Desertic regions from North Africa have been identified as the most significant source area for crustal particles, with a high content of Al and Ti. Atlantic ocean regions have been identified as weak to intermediate source areas of Na, supporting the marine source identified by the factor analysis. Then the influence of remote natural sources on the PM10 levels in central Spain has been detected by the use of single components as tracers, even at urban sites highly affected by traffic. [Copyright &y& Elsevier]

We assessed 2005─2018 data series of NO, NO 2 , and O 3 surface measurements, meteorological data and remote sensing of tropospheric NO 2 by OMI-NASA in the Guadalquivir Valley (GV, Andalucía). The GV is one of the Spanish atmospheric basins with the most exceedances of the EU's hourly O 3 information threshold (180 μg O 3 m−3). We aimed to deepen understanding of the phenomenology of O 3 episodes in the GV, quantify local and regional contributions from long-range transported O 3 , and identify key episodes and atmospheric parameters to validate modeling tools for the assessment of O 3 abatement policies with acceptable uncertainty levels. A significant proportion of acute O 3 episodes (defined as episodes of 1–7 consecutive days, when very high hourly O 3 concentrations are recorded) in the GV is caused by long-range transported contributions in addition to the regional accumulation of pollution which is, in most cases, driven by the vertical recirculation of air masses, as described in several basins of the Iberian Peninsula. In these episodes, high O 3 arises from the fumigation of high reserve recirculated strata as the boundary layer grows, sea-breeze transport of O 3 and precursors, local formation, and long-range transport. The most acute episodes are recorded close to Sevilla, probably because of the mix of precursors from the urban areas and the petrochemical industry of Huelva. We quantified the average O 3 contributions to O 3 concentrations in Sevilla during these episodes as 53% background levels before the episode (defined as the concentration measured at the coastal remote sites at the beginning of the pollution episode, when the Atlantic air masses transport background O 3 from synoptic air mass transport), 22% accumulation throughout the episode, and 25% of daily local and regional contribution to the average 8h-daily maxima (157 μg O 3 m−3). Thus, a maximum decreasing potential of 74 μg O 3 m−3 (47%) of the average 8h-daily maxima can be expected when applying abatement measures to reduce O 3 precursors in the day before the start of an episode and until the end of the episode. Our results demonstrate that it is crucial to meteorologically forecast the occurrence of such recirculation and accumulation processes in the GV basin. • A 2005─2018 evaluation of high ozone pollution in the Guadalquivir Valley. • Frequent ozone accumulation driven by vertical recirculation in the Valley. • Information threshold exceeded in Sevilla (>3 h yr−1), target value in the Valley (>50 day yr−1). • Quantification of O 3 contributions during the most acute episodes in Sevilla. • Significant maximum O 3 abatement potential: 47% (74 μg m−3) of max 8h-daily concentration. [ABSTRACT FROM AUTHOR]

• Inorganic trace pollutants are studied in a coal-fired power station in China. • The aqueous (NH 4) 2 SO 4 slurry (pH 3.2) is enriched in inorganic trace pollutants. • NH 3 -FGD performance for the retention efficiency of trace pollutants is questioned. • Acidic conditions of the aqueous (NH 4) 2 SO 4 slurry could lead to low FGD efficiencies. • Operating conditions may affect Hg fate across the PCC-SCR-ESP-NH 3 -FGD. The behaviour and speciation of inorganic trace pollutants were studied in a 270 MWh coal-fired power station equipped with denitrification (DeNOx)-based selective catalytic reduction (SCR), electrostatic precipitators (ESP) and ammonia flue gas desulphurisation (NH 3 -FGD) controls. The aqueous (NH 4) 2 SO 4 slurry (pH 3.2) showed remarkably high concentrations of SO 4 2−, Cl−, Fe, NH 4 +, PO 4 3−, and F− and was substantially enriched in multiple trace pollutants, e.g. Mn, Ni, Zn, and As, which can be ascribed to the diffusion of gaseous pollutants released during combustion and to the partial dissolution of fly ash (FA) particles entrained in the flue gas FGD. These processes were favoured by the iteration of the FGD water re-circulation cycles within the scrubber. Three major unresolved performance issues remain for the NH 3 -FGD with respect to the retention efficiency of major and trace pollutants: (i) the high concentration of soluble salts and major and minor trace elements in the aqueous (NH 4) 2 SO 4 slurry could lead to entrainment of droplets and particles with the outgoing (OUT)-FGD gas; (ii) the ionic strength, as a result of the high concentration of the elements associated with soluble salts and major and minor elements, could lead to diminishing diffusivity of gaseous pollutants into the aqueous phase, where these are supposed to dissolve; and (iii) the acidic conditions of the aqueous (NH 4) 2 SO 4 slurry, caused by Fe-hydrolysis, could lead to low FGD efficiencies. Operating conditions at this power station affect Hg partitioning and fate across the PCC-SCR-ESP-NH 3- FGD. [ABSTRACT FROM AUTHOR]

• Surface and air samples from buses and subway trains were PCR-tested for SARS-CoV-2. • Evidence for fragments of viral RNA was found in 30 out of 82 samples. • The potential infectivity of these samples however is considered to be extremely low. • The data emphasise the importance of disinfection and hygiene in public transport. • Modelling in-bus infection probability shows forced ventilation greatly reduces risk. Given the widespread concern but general lack of information over the possibility of SARS-CoV-2 infection in public transport, key issues such as passenger personal hygiene, efficient air circulation systems, and the effective disinfection of frequently touched surfaces need to be evaluated to educate the public and diminish the risk of viral transmission as we learn to live with the ongoing pandemic. In this context we report on a study involving the collection of 99 samples taken from inside Barcelona buses and subway trains in May to July 2020. From this sample group 82 (58 surface swabs, 9 air conditioning (a/c) filters, 3 a/c dust, 12 ambient air) were selected to be analysed by RT-PCR for traces of the SARS-CoV-2 virus. Thirty of these selected samples showed evidence for one or more of 3 target RNA gene regions specific for this virus (IP2, IP4, E). Most (24) of these 30 samples showed positivity for only 1 of the 3 RNA targets, 4 samples yielded 2 targets, and 2 samples provided evidence for all 3 targets. RNA remnants were more common in surface swabs from support bars (23 out of 58) than in ambient air inside the vehicles (3 out of 12), with relatively higher concentrations of viral RNA fragments in buses rather than in trains. Whereas subway train a/c filters examined were all virus-free, 4 of the 9 bus a/c filter/dust samples yielded evidence for viral RNA. After nocturnal maintenance and cleaning most buses initially yielding positive results subsequently showed elimination of the RT-PCR signal, although signs of viral RNA remained in 4 of 13 initially positive samples. The presence of such remnant viral traces however does not demonstrate infectivity, which in the present study is considered unlikely given the fragmentary nature of the gene targets detected. Nevertheless, best practice demands that close attention to ventilation systems and regular vehicle disinfection in public transport worldwide need to be rigorously applied to be effective at eliminating traces of the virus throughout the vehicle, especially at times when COVID-19 cases are peaking. Additionally, infectivity tests should be implemented to evaluate the efficiency of disinfection procedures to complement the information resulting from RT-PCR analysis. Modelling the probability of infection whilst travelling in buses under different scenarios indicates that forced ventilation greatly reduces the risk. [ABSTRACT FROM AUTHOR]

We analysed long-term datasets of ambient air concentrations of gaseous pollutants, black carbon (BC) and particle size distributions at an urban background air quality station (Barcelona, Spain; 2013–2019) and a regional background station (Montseny, Spain; 2014–2019). Using BC as a tracer of primary emissions, we segregated the aerosol load in modes and analysed their trends, considering all-year data and seasons separately. We also applied the positive matrix factorisation (PMF) receptor model to the particle size distributions to identify different sources that contribute to the particle number concentration. Our results show that the number concentration of primary particles decreased at the urban and regional background stations (−4.1 and −4.7% per year, respectively) along the period of study. This decrease was also observed for primary particles in the nucleation, Aitken and accumulation modes separately. This change leads to a decrease in condensation sinks (CS, −3.1 and −5.6% per year), that, together with an increase in temperatures (+1.5% per year in the urban background; +1.4% per year in the regional background), results in a markedly increasing trend in the contribution of new particle formation to the total number particle concentration (+17.7% and +11.9% per year). The total particle number concentration decreased in the urban background (−2.5% per year), whereas the trend increased for the regional background (+3.0% per year). The latter result is in contrast to most literature reports and is most likely due to higher insolation and increased biogenic VOC (BVOC) emissions that would enhance photonucleation, along with a marked decrease in the CS. An increasing trend in H 2 SO 4 concentrations driven by increasing SO 2 concentrations (+11.1% per year) could also be favouring the formation of new particles in the regional background, but it is not clear that the increasing trend in SO 2 is real or it is related to a faulty maintenance of the instrumentation. Overall, we conclude that decreasing primary emissions results in a decrease in the total number concentrations of urban aerosols, despite the increase in the formation of new particles by photonucleation. Moreover, the total particle number concentration of regions downwind of the urban areas increases because new particle formation is more favoured and compensates for the primary particles' number concentration decrease. • Decreasing traffic emissions in cities could favour photonucleation in high-insolated rural areas. • We measured gaseous pollutants, black carbon and particle size distributions. • We statistically analysed trends and applied positive matrix factorisation receptor modelling. • Reducing emissions in cities increases the number of particles in nearby rural areas. • Policies aimed at improving air quality in cities may negatively affect nearby rural regions. [ABSTRACT FROM AUTHOR]

Wet and dry aerosol deposition samples were collected from September 2010 to August 2012 at a remote background site in the Mallorca Isle (Western Mediterranean). Ions and major and trace elements were determined in soluble and insoluble fractions. Temporal variations of chemical components are discussed and interpreted. The overall pattern associated to long-range-transport air masses is studied: Dry/Wet deposition ratios, charges and composition depend clearly on the meteorological scenario. E.g. Dry/Wet ratio is 1:1 when air comes from North Africa, in contrast to a 1:9 ratio under the mainland Europe influence. Moreover, an innovating source apportionment study was conducted integrating both dry and wet deposition samples. Six sources were revealed, including marine aerosols (32%); two different mineral factors, African dust (15%) and regional dust (12%); two anthropogenic factors, one related to road traffic (8%) and another to regional sources (17%); and a mixed factor having biomass burning emissions and others sources (17%). Temporal variations and influence from long-range-transport air masses are also investigated. Fertilization deposition trends have also been explored, observing nutrients settling, as well as nitrate and sulphate, due to their agricultural interest. An important peak during January–February 2012 is studied in depth. Having in mind the strong impact of African dust on the global deposition budget, the analysis of elemental ratios between key dust components was investigated in order to identify major source areas affecting Western Mediterranean: Western Sahara, Algeria-Hoggar Massif and Tunisia-Libya. Differences among these regions are evident. E.g. the impact of industrial emissions is well-detected under outbreaks from Tunisia-Libya, with relatively high content of Ni and Pb. Unlabelled Image • Dry Vs Wet, Soluble Vs Insoluble, Deposition fluxes in the Western Mediterranean • Source apportionment study integrating Dry and Wet Deposition results • Comparative of Western Mediterranean Depositions • African dust and nutrients deposition in the Western Mediterranean, case studies • Dry and Wet chemical composition from Northern African Dust Source Areas [ABSTRACT FROM AUTHOR]

Road dust resuspension has a significant contribution to the atmospheric particulate matter levels in urban areas, but loadings, emission factors, and chemical source profiles vary geographically, hampering the accuracy of emission inventories and source contribution estimates. Given the dearth of studies on the variability of road dust, in the present study, an in-situ resuspension chamber was used to collect PM 10 samples from seven representative streets in Viana do Castelo, the northernmost coastal city in Portugal. PM 10 samples were analysed for organic and elemental carbon by a thermo-optical technique, elemental composition by ICP-MS and ICP-AES, and organic constituents by GC–MS. Emission factors were estimated to be, on average, 340 and 41.2 mg veh−1 km−1 for cobbled and asphalt pavements, respectively. Organic carbon accounted for 5.56 ± 1.24% of the PM 10 mass. Very low concentrations of PAHs and their alkylated congeners were detected, denoting a slight predominance of petrogenic compounds. Si, Al, Fe, Ca and K were the most abundant elements. The calculation of various geochemical indices (enrichment factor, geoaccumulation index, pollution index and potential ecological risk) showed that road dust was extremely enriched and contaminated by elements from tyre and brake wear (e.g. Sb, Sn, Cu, Bi and Zn), while lithophile elements showed no enrichment. For As, the geochemical and pollution indices reached their maximum in the street most influenced by agricultural activities. Sb, Cd, Cu and As can pose a very high ecological risk. Sb can be regarded as the pollutant of highest concern, since it represented 57% of the total ecological risk. Hazard indices higher than 1 for some anthropogenic elements indicate that non-carcinogenic effects may occur. Except for a street with more severe braking, the total carcinogenic risks can be considered insignificant. Unlabelled Image • The thoracic fraction of road dust was sampled with an in-situ resuspension chamber. • Emission factors of 340 (cobbled) and 41 (asphalt) mg PM 10 veh−1 km−1 were estimated. • Road dust was extremely contaminated by elements from tyre and brake wear. • Elements from tyre and brake wear can pose a very high ecological risk. • High pollution indices for arsenic in samples impacted by agricultural activities. [ABSTRACT FROM AUTHOR]

The sorption of phosphate by K-zeolites synthesized from fly ash (FA) by hydrothermal conversion is investigated in this study. The aim is the synthesis of Ca bearing K-zeolites to recover phosphate from urban and industrial wastewater effluents. The loaded zeolites are considered as a by-products rich in essential nutrients such K and P (KP1) with a potential use as slow release fertilizer. A number of synthesis conditions (temperature, KOH-solution/FA ratio, KOH concentration, and activation time) were applied on two FA samples (FA-TE and FA-LB) with similar glass content but different content of crystalline phases, to optimize the synthesis of a zeolitic sorbent suitable for the subsequent phosphate uptake. Merlinoite and W rich zeolitic products synthesized from FA-LB and FA-TE were found to have sorption properties for phosphate removal. A maximum phosphate sorption capacity of 250 mgP-PO 4 /g and 142 mgP-PO 4 /g for the zeolitic products selected (KP1-LB and KP1-TE, respectively) was achieved. The dominant phosphate sorption mechanism, in the pH range (6–9) of treated wastewater effluents, indicated that sorption proceeds via a diffusion-controlled process involving phosphate ions coupled with calcium supply dissolution from K-zeolitic products and subsequent formation of brushite (CaHPO 4 2H 2 O(s)). The phosphate loaded sorbent containing a relatively soluble phosphate mineral is appropriate for its use as a synthetic slow release fertilizer. The simultaneous valorisation of fly ash waste and the P recovery from treated wastewaters effluents, (a nutrient with scarce natural resources and low supply) by obtaining a product with high potential for land restoration and agriculture will contribute to develop one example of circularity. Unlabelled Image • Activated K zeolites were produced from two fly ash. • Ca bearing K-zeolites, Merlinoite and W rich zeolitic were synthetized. • Ca-bearing K-Zeolites are suitable carriers to recover P from wastewater. • Phosphate removal process by Ca-bearing K zeolites involves the formation of (CaHPO 4 (s)). • Brushite (CaHPO 4 (s)) has suitable properties as a slow-release fertilizer. [ABSTRACT FROM AUTHOR]

Lockdown measures came into force in Spain from March 14th, two weeks after the start of the SARS-CoV-2 epidemic, to reduce the epidemic curve. Our study aims to describe changes in air pollution levels during the lockdown measures in the city of Barcelona (NE Spain), by studying the time evolution of atmospheric pollutants recorded at the urban background and traffic air quality monitoring stations. After two weeks of lockdown, urban air pollution markedly decreased but with substantial differences among pollutants. The most significant reduction was estimated for BC and NO2 (−45 to −51%), pollutants mainly related to traffic emissions. A lower reduction was observed for PM10 (−28 to −31.0%). By contrast, O 3 levels increased (+33 to +57% of the 8 h daily maxima), probably due to lower titration of O 3 by NO and the decrease of NOx in a VOC-limited environment. Relevant differences in the meteorology of these two periods were also evidenced. The low reduction for PM10 is probably related to a significant regional contribution and the prevailing secondary origin of fine aerosols, but an in-depth evaluation has to be carried out to interpret this lower decrease. There is no defined trend for the low SO 2 levels, probably due to the preferential reduction in emissions from the least polluting ships. A reduction of most pollutants to minimal concentrations are expected for the forthcoming weeks because of the more restrictive actions implemented for a total lockdown, which entered into force on March 30th. There are still open questions on why PM10 levels were much less reduced than BC and NO 2 and on what is the proportion of the abatement of pollution directly related to the lockdown, without meteorological interferences. Unlabelled Image • NO 2 and BC concentrations were reduced by half during the lockdown (more windy and wet) period. • PM10 decreased but in a much lower proportion, causes for the lower abatement are still unknown • O 3 concentrations increased by around 50% [ABSTRACT FROM AUTHOR]

Biomass burning is a major air pollution problem all around the world. However, the identification and quantification of its contribution to ambient aerosol levels is a difficult task due to the generalized lack of observations of molecular markers. This paper presents the results of a yearlong study of organic constituents of the atmospheric aerosol at a rural site in southern Spain (Villanueva del Arzobispo, Jaén). Sampling was performed for PM 10 and PM 2.5 , and a total of 116 and 115 samples, respectively, were collected and analyzed by GC/MS, quantifying 77 organic compounds. Higher levels of organic pollutants were recorded from November to March, coinciding with the cold season when domestic combustion is a common practice in rural areas. This jointly with adverse meteorological conditions, e.g. strong atmospheric stability, produced severe pollution episodes with high PM x ambient levels. High daily concentrations of tracers were reached, up to 26 ng m−3 for B(a)P and 6065 ng m−3 for levoglucosan in PM 2.5 , supporting that biomass burning is a major source of pollution at rural areas. A multivariate statistical study based on factor and cluster analysis, was applied to the data set with the aim to distinguish sources of organic compounds. The main resulting sources were related with biomass combustion, secondary organic aerosol (SOA), biogenic emissions, lubricating oil and soil organic components. A preliminary organic source profile for olive wastes burning was evaluated, based on cluster results, showing anhydrosacharides and xylitol are the main emitted compounds, accounting for more than 85% of the quantified compounds. Other source compounds were fatty acids, diacids, aliphatics, sugars, sugar alcohols, PAHs and quinones. • Air pollution exceeds PM10 & PM2.5 limit values in Spanish rural areas in winter. • GC/MS characterization of 77 polar and apolar organic compounds. • Daily concentrations up to 26 ng m−3 of Benzo(a)pyrene were reached. • Biomass burning was identified as the main source of many organic compounds. • Other sources were biogenic emissions, SOA, soil dust and lubricating oil. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the population exposure to PM 2.5 , and to quantify the effect of eliminating short-term pollution peaks on the number of cause-specific deaths, the number of years of life lost (YLL), and economic losses attributed to exposure to PM 2.5 in 25 Iranian cities with available air quality data. Number of deaths and YLL were estimated with AirQ + software tool using available concentration-response functions and life table approach. Furthermore, the value of lost life in each city were calculated using the Value of Statistical Life (VSL) method. Two scenarios were defined; Scenario A, considering actual observed concentrations to estimate the real health effects of PM 2.5 , and Scenario B, controlling for the effect of air pollution episodes. The results showed that the annual average concentrations of PM 2.5 in cities were 1.5–6.1 times higher than the guideline value of WHO (10 μg/m³). The total number of all-cause deaths due to long-term exposure exceeding WHO air quality guideline level was 13321 (95% C.I.: 8837–17378) cases per year in all cities. The total numbers of chronic obstructive pulmonary disease (COPD), lung cancer, ischemic heart disease (IHD), and stroke deaths attributed to the exposure were 274, 315, 1536, and 963 cases, respectively. The total number of YLL over 10 years period in all 25 cities was 486,289 years and the loss of life expectancy ranged from 0.43 to 1.87 years. The sum of economic losses due to lost life exceeded 5.8 billion USD. Except for some cities, avoiding highly polluted days in Scenario B would result in only 5% reduction in overall health or economic effects. These results indicate an urgent need for new comprehensive plans to tackle air pollution in Iranian cities focused on reduction of long term average pollution levels since programs for avoiding highly polluted days lead to a limited health benefits only. • In all cities, sum of all-cause deaths due to exposure to PM 2.5 was 13321. • In all cities, the total number of YLL was about 500,000 years. • The loss of life expectancy ranged from 0.43 to 1.87 years. • The sum of economic losses due to lost life exceeded 5.8 billion USD. • Avoiding highly polluted days resulted in only 5% reduction in health effects. [ABSTRACT FROM AUTHOR]

Inhalable particulate matter (size <2.5 μm: PM 2.5) inside commuting and tourist buses moving through the city of Barcelona, Spain, was chemically analysed. The analyses show PM dominated by organic carbon (mostly 10–20 μg/m3) and elemental carbon (mostly 3–6 μg/m3; OC/EC = 3.4), followed by SO 4 2, Fe, Ca, K, Al 2 O 3 , Mg, and Na, with calculated mineral content being around one third that of total carbon. Elemental carbon levels are higher inside diesel buses than those powered by natural gas or electricity, and higher in the upper floor of open-top double decker tourist buses than in the lower floor. Overall, major element concentrations inside the buses are typically 2–8 times higher than 24 h-averaged urban background levels, although some metallic trace elements, notably Cu and Sb, are exceptionally enriched due to the presence of brake particles, especially on routes involving higher gradients and therefore more brake use. In contrast, Cu and Sb concentrations in electric buses are unexceptional, presumably because these buses rely more on regenerative braking and are hermetically sealed when moving. Seasonal differences reveal PM to be more mineral in winter (Al 2 O 3 1.3 μg/m3 vs. summer average of 0.3 μg/m3), with summer enrichment in Na, Mg, P, V, Ni and SO 4 2− being attributed to marine aerosols contaminated by port emissions. Source apportionment calculations identify 6 main factors: road dust resuspension, metalliferous (brake wear and metallurgy), local urban dust, secondary sulphate and shipping (6%), vehicle exhaust (19%), and an indoor source (46%) interpreted as likely related to the textile fibres and skin flakes of bus occupants. Volatile Organic Compounds measured inside all buses except one were dominated by 2-Methylpentane (14–36 μg/m3), Toluene (10–30 μg/m3), Xylene isomers (10–28 μg/m3, with m- » o- > p-Xylene) and n-Pentane (5–15 μg/m3). ƩBTEX concentrations were <70 μg/m3, with Toluene being commonest, followed by m-Xylene, with p-Xylene, o-Xylene and Ethylbenzene each below 7 μg/m3 and Benzene concentrations always less than the EU limit value of 5 μg/m3. The VOCs mixture is similar to that recently reported from inside Barcelona taxis (although inside the larger volume bus VOC concentrations are lower than in the taxis) and is interpreted as providing a chemical fingerprint characterising traffic-contaminated ambient air in the city road environment. The notable exception to the VOC content was a brand new hybrid diesel bus still offgassing volatiles to such an extent that Ʃ(alkane + alkene + aromatic) indoor concentrations exceeded 800 μg/m3, with ƩBTEX ten times higher than normal. • Interior bus air chemistry can be influenced both by route taken and bus model. • Carbon and most metal concentrations are much higher in buses than urban background. • Enhanced levels of Cu and Sb are attributed to brake particles entering the bus. • Inhalable PM are mostly textile fibres, skin flakes, vehicle exhaust and brake wear. • New buses show much higher VOC signature due to off-gassing of interior materials. [ABSTRACT FROM AUTHOR]

Based at Izaña Observatory (~2400 m a.s.l. in Tenerife), we performed 1-h resolution measurements of elemental composition of dust in the Saharan Air Layer (SAL) and studied the variability of the ratios of these elements to aluminium (elemental ratios). In a period (~1 week) of continuous dust presence (50–200 μg/m3), we observed rapid variations of dust composition; some elemental ratios changed by a factor 2 in a few (5–8) hours. The lowest variability (Normalized Variability Range, %) was found for Si/Al (9%) and Fe/Al (9%), followed by the ratios of K, Ti, Mg, Mn, Ca and Sr to Al (20–80%), and the highest for S/Al, Na/Al and Cl/Al (110–160%) and a number of trace metals (Cr, Cu, Ni, Zn, Zr) and Br (>200%). This variability was induced by the alternating impacts of three of the large North African dust sources: NE Algeria (rich in evaporite minerals bearing Ca, S, Sr, K and Mg and in illite mineral), Western Sahara to Bechar region (containing Na, S and Cl rich Yermosol soils) and SW Sahara – Western Sahel (rich in illite and hematite). We traced the variability in large-scale meteorology using the so-called North African Dipole Intensity (NAFDI: strength of the subtropical Saharan high -Morocco-to the monsoon tropical low -Nigeria-). The mobilization of dust from the different sources was associated with westward propagating Harmattan pulses linked to the change of phase of NAFDI (- to +), the associated westward shifts of the Saharan Heat Low and convective monsoon inflow. We found a correlation between dust composition in the SAL and NAFDI: moderate NAFDI values (0 to +2.5) were associated with Ca, K, Na, Mg and S rich dust linked to dust sources in NE Algeria, whereas higher NAFDI values (+2.5 to +4) were linked to Fe rich dust (Ca, Na and S depleted) linked to dust sources in SW Sahara – Western Sahel. The results of this study also show that some trace elements (Br, Cr, Ni, Zn and Zr) are influenced by industrial emissions into North Africa. Image 1 • Dust composition changes rapidly, ~5–8 h, in the Saharan Air Layer. • North African Dipole Intensity NAFDI traces the variability of summer meteorology. • Positive phase of NAFDI enhances dust export to the North Atlantic. • Negative phase of NAFDI enhances dust export to the Western Mediterranean. • NAFDI connects meteorology, sources and dust composition in the Saharan Air Layer. [ABSTRACT FROM AUTHOR]

• Ultrafine particle sources were identified and quantified in four European cities. • Common sources were Photonucleation , different Traffic sources, and Secondary. • Maximum contribution of traffic sources ranged 71–94% of total particle number. • Airport emissions contributed to nucleation particles in urban background areas. Ultrafine particles (UFP) are suspected of having significant impacts on health. However, there have only been a limited number of studies on sources of UFP compared to larger particles. In this work, we identified and quantified the sources and processes contributing to particle number size distributions (PNSD) using Positive Matrix Factorization (PMF) at six monitoring stations (four urban background and two street canyon) from four European cities: Barcelona, Helsinki, London, and Zurich. These cities are characterised by different meteorological conditions and emissions. The common sources across all stations were Photonucleation , traffic emissions (3 sources, from fresh to aged emissions: Traffic nucleation , Fresh traffic – mode diameter between 13 and 37 nm, and Urban – mode diameter between 44 and 81 nm, mainly traffic but influenced by other sources in some cities), and Secondary particles. The Photonucleation factor was only directly identified by PMF for Barcelona, while an additional split of the Nucleation factor (into Photonucleation and Traffic nucleation) by using NO x concentrations as a proxy for traffic emissions was performed for all other stations. The sum of all traffic sources resulted in a maximum relative contributions ranging from 71 to 94% (annual average) thereby being the main contributor at all stations. In London and Zurich, the relative contribution of the sources did not vary significantly between seasons. In contrast, the high levels of solar radiation in Barcelona led to an important contribution of Photonucleati on particles (ranging from 14% during the winter period to 35% during summer). Biogenic emissions were a source identified only in Helsinki (both in the urban background and street canyon stations), that contributed importantly during summer (23% in urban background). Airport emissions contributed to Nucleation particles at urban background sites, as the highest concentrations of this source took place when the wind was blowing from the airport direction in all cities. [ABSTRACT FROM AUTHOR]

• Hazard prediction of particulate matter (PM) by the Machine learning (ML) models. • Selection of key features using the simulated annealing (SA) method. • Good performance of the ML models in PM modeling (Accuracy > 87%; Precision > 86%). Air pollution, and especially atmospheric particulate matter (PM), has a profound impact on human mortality and morbidity, environment, and ecological system. Accordingly, it is very relevant predicting air quality. Although the application of the machine learning (ML) models for predicting air quality parameters, such as PM concentrations, has been evaluated in previous studies, those on the spatial hazard modeling of them are very limited. Due to the high potential of the ML models, the spatial modeling of PM can help managers to identify the pollution hotspots. Accordingly, this study aims at developing new ML models, such as Random Forest (RF), Bagged Classification and Regression Trees (Bagged CART), and Mixture Discriminate Analysis (MDA) for the hazard prediction of PM10 (particles with a diameter less than 10 µm) in the Barcelona Province, Spain. According to the annual PM10 concentration in 75 stations, the healthy and unhealthy locations are determined, and a ratio 70/30 (53/22 stations) is applied for calibrating and validating the ML models to predict the most hazardous areas for PM10. In order to identify the influential variables of PM modeling, the simulated annealing (SA) feature selection method is used. Seven features, among the thirteen features, are selected as critical features. According to the results, all the three-machine learning (ML) models achieve an excellent performance (Accuracy > 87% and precision > 86%). However, the Bagged CART and RF models have the same performance and higher than the MDA model. Spatial hazard maps predicted by the three models indicate that the high hazardous areas are located in the middle of the Barcelona Province more than in the Barcelona's Metropolitan Area. [ABSTRACT FROM AUTHOR]

• The brines in PG ponds are extremely enriched in F, Na, Cl, Ni, Cd, Mn, Cu, Zn, and U. • Brine composition is strongly seasonal and spatial dependent. • The enrichment in aged brines is caused by precipitation and re-dissolution processes. • Brine evaporation produces multi-layered trace-element rich precipitates. The present study focuses on the geochemistry of large phosphogypsum deposits in Huelva (SW Spain). Phosphogypsum slurry waste from fertiliser production was disposed in large ponds containing aqueous waste (i.e. brines) and exposed to weathering. These evaporation ponds were found to be dynamic environments far from attaining steady state conditions where a number of trace pollutants are subjected to temporal variations in response to changing environmental conditions. Chemical, mineralogical and morphological data were used to improve our understanding on the dynamics of a large number of elements in the phosphogypsum-brine-evaporation deposits system. Weekly sampling of brines over the course of 1 yr indicated a substantial enrichment in potentially harmful elements (e.g. As, Cr, Cu, F, Ni, U, V, Zn) present in time-dependent concentrations. The evaporation deposits formed multi-layered precipitates of chlorides, sulphates, phosphates and fluorides containing a large number of pollutants in readily soluble forms. The precipitation sequence revealed a time-dependent composition reflecting alternating precipitation and re-dissolution processes associated with seasonal changes in the local weather conditions. Concatenation of precipitation/re-dissolution stages was found to progressively enrich the brines in pollutants. These findings were supported by the observations from a tank experiment simulating the phosphogypsum-brine-evaporation deposits system under laboratory conditions. Given the substantially high concentrations of pollutants present in mobile forms in the brine-salt system, actions to abate these compounds should be implemented. [ABSTRACT FROM AUTHOR]

Processing granitoid rock for civil engineering, countertops, and paving generates sub-economical (transportation costs exceed their retail value) granite powder sludge. This paper evaluates the possibility of mixing granite waste (GW) produced at the Spanish quarries of Galicia with a second sub-economical substance, Class F coal fly ash (FA <20 wt% CaO). The GW would reduce the leachability of toxic trace elements enriched in Colombian fly ashes and form a sand-like product that could serve as a substitute product and would reduce the costs in industrial concrete and civil engineering projects. To investigate both the capability of the GW to reduce FA leaching (by physical adsorption) and the potential use of the aggregate product as a partial substitute in industrial concrete, the physical (e.g. morphology, crystallographic patterns, and surface area), mineralogical, and chemical (including leachability and chemical composition) properties of the aggregate product were tested. Moreover, properties of the concrete (compressive strength, ion penetration, workability, and electron microscope scanning results (SEM)) were also analyzed. The use of the end scrubbed product in the concrete mixture was found to enhance the performance of the concrete mixture, reducing the leaching of the hazardous elements, and improving the concrete produced. Image 1 • Evaluate the potential of using coal fly ashes and granitoid waste powder as partial substitute to natural sand in concrete. • Fixation process: aluminate/silicate anions of the fly ash–Ca2+ as mediators-silicate anions of the granitoid waste powder. • End products (aggregates and concrete) are considered to have better performances and were found as non-hazardous. • Original method could reduce environmental pollution by reducing use of natural sources, waste storing and energy demand. [ABSTRACT FROM AUTHOR]

Sub-Saharan Africa (SSA) has the highest proportion of people using unclean fuels for household energy, which can result in products of incomplete combustion that are damaging for health. Black carbon (BC) is a useful marker of inefficient combustion-related particles; however, ambient air quality data and temporal patterns of personal exposure to BC in SSA are scarce. We measured ambient elemental carbon (EC), comparable to BC, and personal exposure to BC in women of childbearing age from a semi-rural area of southern Mozambique. We measured ambient EC over one year (2014–2015) using a high-volume sampler and an off-line thermo-optical-transmission method. We simultaneously measured 5-min resolved 24-h personal BC using a portable MicroAeth (AE51) in 202 women. We used backwards stepwise linear regression to identify predictors of log-transformed 24-h mean and peak (90th percentile) personal BC exposure. We analyzed data from 187 non-smoking women aged 16–46 years. While daily mean ambient EC reached moderate levels (0.9 μg/m3, Standard Deviation, SD: 0.6 μg/m3), daily mean personal BC reached high levels (15 μg/m3, SD: 19 μg/m3). Daily patterns of personal exposure revealed a peak between 6 and 7 pm (>35 μg/m3), attributable to kerosene-based lighting. Key determinants of mean and peak personal exposure to BC were lighting source, kitchen type, ambient EC levels, and temperature. This study highlights the important contribution of lighting sources to personal exposure to combustion particles in populations that lack access to clean household energy. • We quantified ambient EC and personal BC exposure in semi-rural Mozambique. • Kerosene-based lighting and ambient EC were the major predictors of personal BC. • Kerosene users were 81% more exposed to BC than electricity users. • Highest personal BC peaks (>35 μg/m3) were attributable to kerosene-based lighting. • Interventions to replace fuel-based lighting should be implemented and evaluated. [ABSTRACT FROM AUTHOR]