Utilizing spiders for biomonitoring air pollution from road traffic: a novel approach and preliminary findings.

Polycyclic aromatic hydrocarbons (PAHs) are air pollutants generated mainly by fuel combustion, industry, and other anthropogenic sources. The level of these pollutants can be assessed by employing biomonitors, a cost-effective and less contaminating alternative than conventional methods. In the present study, we aimed to investigate whether spiders inhabiting areas around a major city like Córdoba, Argentina, adsorb and retain PAHs in their exoskeletons. Additionally, we aimed to determine if spiders' life traits influence their capacity to accumulate PAHs and explore potential relationships between PAH levels and the types of roads where they were collected. Specimens of a funnel-shaped web spider (Aglaoctenus lagotis) and an orb-weaver (Metepeira spp.) were collected from roadsides. Roads were classified into four categories based on their traffic intensity. Using high-performance liquid chromatography (HPLC), we identified 15 different PAHs. Both species exhibited varying concentrations of PAHs, although Metepeira spp. showed 15-18 times higher PAH levels compared to A. lagotis. Moreover, A. lagotis individuals living alongside highways accumulated up to six times more PAHs compared to those along other road types. These findings suggest that spiders' life traits may influence pollutant concentrations. Our study demonstrates that spiders near roads are exposed to and accumulate PAHs on their exoskeletons, likely sourced from petrogenic vehicular emissions, highlighting their value as biomonitors and emphasizing the need for mitigation measures to address air pollutants emitted from mobile sources.

Urban air pollution evaluation in downtown streets of a medium-sized Latin American city using AERMOD dispersion model.

The transport sector is considered the largest contributor of air pollutants in urban areas, mainly on-road vehicles, affecting the environment and human health. Bahía Blanca is a medium-sized Latin American city, with high levels of traffic in the downtown area during peak hours. In this regard, it is necessary to analyze air pollution using an air quality model considering that there are no air pollutant measurements in the central area. Furthermore, this type of study has not been carried out in the region and since the city is expected to grow, it is necessary to evaluate the current situation in order to make effective future decisions. In this sense, the AERMOD model (US-EPA version) and the RLINE source type were used in this work. This study analyzes the variations of pollutant concentrations coming from mobile sources in Bahía Blanca's downtown area, particularly carbon monoxide (CO) and nitrogen oxides (NOx) during the period Jul-2020 to Jun-2022. It is interesting to note the results show the maximum concentration values detected are not directly associated with maximum levels of vehicle flow or emission rates, which highlights the importance of meteorological parameters in the modeling. In addition, alternative scenarios are proposed and analyzed from a sustainable approach. Regarding the scenario analysis, it can be concluded that diesel vehicles have a large influence on NOx emissions. Moreover, restrictions as strict as those proposed for a Low Emission Zone would be less applicable in the city than alternative temporary measures that modify traffic at peak hours.

Assessing heavy metal contamination in a Brazilian metropolis: a case study with a focus on (bio)indicators.

The continuous expansion of the global vehicle fleet poses a growing threat to environmental quality through heavy metal contamination. In this scenario, monitoring to safeguard public health in urban areas is necessary. Our study involved the collection of 36 street dust and 29 moss samples from roads of a Brazilian metropolis (Recife) with varying traffic intensities as follows: natural reserve (0 vehicles per day), low (< 15,000 vehicles per day), medium (15,000-30,000 vehicles per day), and high (> 30,000 vehicles per day). ICP-AES analysis was performed to determine the concentrations of nine potentially toxic metals (Ba, Cd, Cr, Cu, Mn, Ni, Pb, V, and Zn) to assess the influence of vehicular flow on urban contamination. In the street dust samples, the mean metal concentrations (mg kg-1) exhibited the following order: Ba (503.7) > Mn (303.0) > Zn (144.4) > Cu (95.3) > Cr (56.1) > Pb (34.2) > V (28.7) > Ni (11.3) > Cd (1.5). Conversely, in the moss samples, the metal concentration order was as follows (mg kg-1): Mn (63.8) > Zn (62.5) > Ba (61.0) > Cu (17.7) > Cr (8.0) > V (7.3) > Pb (7.0) > Ni (2.9) > Cd (0.3). Roads with higher traffic volumes exhibited the highest metal enrichments in moss samples for all metals and in dust samples for Cd, Cr, Mn, Ni, and V. However, dust from low-flow roads had higher enrichments for Ba, Cu, and Zn, indicating the influential role of other traffic-related factors in metal deposition. Our findings highlight traffic flow as the predominant source of pollution in urban centers, with both street dust and moss serving as sensitive indicators of metal input attributable to vehicular traffic. These indicators offer valuable insights for urban quality monitoring and pollution control efforts.

Methylsiloxanes from Vehicle Emissions Detected in Aerosol Particles.

Methylsiloxanes have gained growing attention as emerging pollutants due to their toxicity to organisms. As man-made chemicals with no natural source, most research to date has focused on volatile methylsiloxanes from personal care or household products and industrial processes. Here, we show that methylsiloxanes can be found in primary aerosol particles emitted by vehicles based on aerosol samples collected in two tunnels in São Paulo, Brazil. The aerosol samples were analyzed with thermal desorption-proton transfer reaction-mass spectrometry (TD-PTR-MS), and methylsiloxanes were identified and quantified in the mass spectra based on the natural abundance of silicon isotopes. Various methylsiloxanes and derivatives were found in aerosol particles from both tunnels. The concentrations of methylsiloxanes and derivatives ranged 37.7-377 ng m-3, and the relative fractions in organic aerosols were 0.78-1.9%. The concentrations of methylsiloxanes exhibited a significant correlation with both unburned lubricating oils and organic aerosol mass. The emission factors of methylsiloxanes averaged 1.16 ± 0.59 mg kg-1 of burned fuel for light-duty vehicles and 1.53 ± 0.37 mg kg-1 for heavy-duty vehicles. Global annual emissions of methylsiloxanes in vehicle-emitted aerosols were estimated to range from 0.0035 to 0.0060 Tg, underscoring the significant yet largely unknown potential for health and climate impacts.

Assessing heavy metal pollution load index (PLI) in biomonitors and road dust from vehicular emission by magnetic properties modeling.

Vehicular traffic occupies a significant place among the sources of air pollution, due to population and urban growth that has led to an excessive increase in the vehicle fleet worldwide, and in Costa Rica as well. Vehicle emissions generate greenhouse gases (GHGs), particulate matter (PM), and heavy metals (HMs), due to combustion products from fossil-fuel engines, tire wear, and brake linings. HMs are important because they cannot be degraded or destroyed naturally; however, they can be diluted by physicochemical agents and be incorporated into trophic chains where they can be bioaccumulated causing significant negative effects on human well-being and ecological quality. This study aimed to assess the HM pollution load in biomonitors and road dust from vehicular emissions by chemical analyses and magnetic properties modeling. For this purpose, chemical and magnetic property analyses were carried out on samples of road dust and leaves of Cupressus lusitanica Mill. and Casuarina equisetifolia L., which were sampled during 2 different years in the Greater Metropolitan Area of Costa Rica known as GAM. Contamination factor (CF) and pollution load index (PLI) results showed significant metal pollution in some of the study sites. Contamination by the metals V, Cr, and Zn was most commonly present in the biomonitors, and for road dust, they were Cr, Zn, and Pb. The PLI estimates obtained with the validated support vector machine (SVM) magnetic properties models were consistent (sensitivity, specificity, and precision) with those obtained by chemical analysis, demonstrating the feasibility of this method for the identification of this index of contamination.

Reduced commuter exposure to PM2.5 and PAHs in response to improved emission standards in bus rapid transit systems in Mexico.

We evaluated impacts of progressive technological updates to bus rapid transit (BRT) systems on in-cabin concentrations of particulate matter with an aerodynamic diameter ≤2.5 µm (PM2.5), and the various polyaromatic hydrocarbons (PAHs) to which commuters were exposed. PM2.5 samples were collected and real-time concentrations measured from October 2017 to March 2020 inside cabins of BRT buses equipped with Euro IV, V and VI diesel emission standards in the Mexico City Metropolitan Area (MCMA). For effective comparison, similar samplings and measurements were carried out on trains in the MCMA underground (MCU) system. Peak in-cabin PM2.5 concentrations decreased significantly (p < 0.05) by 35% from Euro IV to Euro V buses, and by 80% from Euro IV to Euro VI buses. PM2.5 concentrations inside Euro VI buses were significantly lower (p < 0.05) than in Euro IV and Euro V buses and in underground trains. The in-cabin excess (ICE) of PM2.5 relative to ambient concentrations was significantly (p < 0.05) higher for Euro IV than for Euro V buses during morning the traffic peak, and consistently higher than for Euro VI buses. Indeed, ICEs calculated for Euro VI buses were always lower than those for electricity-powered underground trains. The frequency of hotspots decreased from Euro IV to Euro VI buses due to the combined effect of low emissions and closed, air-conditioned cabins. Concentrations of total PAHs including carcinogenic species also decreased from Euro IV to Euro V buses and were below limits of detection aboard Euro VI buses. This work shows that in real-life conditions, advanced diesel technologies and cabin design significantly reduce commuters' exposure to PM2.5 and to toxic PAH compounds.

Trapping of polycyclic aromatic hydrocarbons in vehicle exhaust using an in-tube extraction device for analysis by gas chromatography-barrier ionization discharge detection.

This work presents a methodology for polycyclic aromatic hydrocarbons (PAHs) trapping from vehicular emissions using an in-tube extraction device (IT-FEx). Trapping selectivity studies were conducted, evaluating the interaction profile between the aromatic compounds and the polymeric phase (composed of polydimethylsiloxane and internal to the IT-FEx devices), as in an aqueous equilibrium system (25 min of sampling), and as in gaseous dynamic phase (30 s of sampling), regarding a qualitative evaluation. The adsorption profiles were similar, with greater affinity for medium-sized PAHs (four aromatic rings) than for the smaller (one to three rings) and larger (five to six rings). The device was attached to a vehicle emission sampler to evaluate the qualitative emission of diesel-powered vehicles. Certain PAHs, such as phenanthrene, fluoranthene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[k]fluoranthene, were effectively trapped by the IT-FEx device and detected by the GC-BID analysis. Finally, it was possible to develop a process that combined the steps of sample preparation and instrumental analysis, using the IT-FEx device and applying it to the gaseous matrix in the dynamic phase; until then, little was elucidated regarding the use of this apparatus. This sampling device, combined with analysis by gas chromatography with a barrier ionization discharge detector (GC-BID), is a powerful tool for identifying many compounds from vehicular emissions and does not require solvents in sample preparation.

An empirical and modelling approach to the evaluation of cruise ships' influence on air quality: The case of La Paz, Mexico.

Maritime activity has diverse environmental consequences impacts in port areas, especially for air quality, and the post-COVID-19 cruise tourism market's potential to recover and grow is causing new environmental concerns in expanding port cities. This research proposes an empirical and modelling approach for the evaluation of cruise ships' influence on air quality concerning NO2 and SO2 in the city of La Paz (Mexico) using indirect measurements. EPA emission factors and the AERMOD modelling system coupled to WRF were used to model dispersions, while street-level mobile monitoring data of air quality from two days of 2018 were used and processed using a radial base function interpolator. The local differential Moran's Index was estimated at the intersection level using both datasets and a co-location clustering analysis was performed to address spatial constancy and to identify the pollution levels. The modelled results showed that cruise ships' impact on air quality had maximum values of 13.66 µg/m3 for NO2 and 15.71 µg/m3 for SO2, while background concentrations of 8.80 for NOx and 0.05 for SOx (µg/m3) were found by analysing the LISA index values for intersections not influenced by port pollution. This paper brings insights to the use of hybrid methodologies as an approach to studying the influence of multiple-source pollutants on air quality in contexts totally devoid of environmental data.

Emission factors for a biofuel impacted fleet in South America's largest metropolitan area.

The Metropolitan Area of São Paulo (MASP) is among the largest urban areas in the Southern Hemisphere. Vehicular emissions are of great concern in metropolitan areas and MASP is unique due to the use of biofuels on a large scale (sugarcane ethanol and biodiesel). In this work, tunnel measurements were employed to assess vehicle emissions and to calculate emission factors (EFs) for heavy-duty and light-duty vehicles (HDVs and LDVs). The EFs were determined for particulate matter (PM) and its chemical compounds. The EFs obtained for 2018 were compared with previous tunnel experiments performed in the same area. An overall trend of reduction of fine and coarse PM, organic carbon (OC), and elemental carbon (EC) EFs for both LDVs and HDVs was observed if compared to those observed in past years, suggesting the effectiveness of vehicular emissions control policies implemented in Brazil. A predominance of Fe, Cu, Al, and Ba emissions was observed for the LDV fleet in the fine fraction. Cu presented higher emissions than two decades ago, which was associated with the increased use of ethanol fuel in the region. For HDVs, Zn and Pb were mostly emitted in the fine mode and were linked with lubricating oil emissions from diesel vehicles. A predominance in the emission of three- and four-ring polycyclic aromatic hydrocarbons (PAHs) for HDVs and five-ring PAHs for LDVs agreed with what was observed in previous studies. The use of biofuels may explain the lower PAH emissions for LDVs (including carcinogenic benzo[a]pyrene) compared to those observed in other countries. The tendency observed was that LDVs emitted higher amounts of carcinogenic species. The use of these real EFs in air quality modeling resulted in more accurate simulations of PM concentrations, showing the importance of updating data with real-world measurements.

Determination of carbonyls and size-segregated polycyclic aromatic hydrocarbons, and their nitro and alkyl analogs in emissions from diesel-biodiesel-ethanol blends.

This study characterizes carbonyls (RCHO), polycyclic aromatic hydrocarbons (PAHs), their nitrated (nitro-PAHs) and alkylated (alkyl-PAHs) in particulate matter in the exhaust emissions of a diesel engine. The measurements were made with a standard engine, often found in vans used in Brazil, fueled with pure commercial diesel and mixtures of 10, 20, and 30% biodiesel with 2, 4, and 6% of ethanol. Particulate matter sampling was carried out with a 10-stage cascade impactor. Chemical analyses for PAHs and their derivatives were conducted using gas phase chromatography-mass spectrometry (GC/MS). RCHO were sampled using impingers with 2,4-DNPH and analyzed using HPLC with UV detection. The results showed that emissions of all the PAHs and their derivatives were reduced with the use of biodiesel and ethanol, with the exception of the blend of 30% biodiesel with 4% ethanol. However, all the RCHO emissions increased with biodiesel and ethanol. High correlations were observed between the emissions of PAHs, alkyl-PAHs and nitro-PAHs, which suggests a similarity in the formation mechanisms of these compounds. All PAHs' emissions have a strong negative correlation with biodiesel content and with RCHO emissions and a medium correlation with ethanol content. In contrast, biodiesel and ethanol with the RCHO emissions lead to a positive correlation coefficient of these compounds which is more pronounced for biodiesel than ethanol.

Source apportionment and health impact assessment of atmospheric particulate matter in the city of São Carlos, Brazil.

In this study, positive matrix factorization method was used for source apportionment of PM10 in the city of São Carlos from 2015 to 2018. The annual mean concentrations of PM10, 15 PAHs, 4 oxy-PAHs, 6 nitro-PAHs, 21 saccharides, and 17 ions in these samples were in the ranges 18.1 ± 6.99 to 25.0 ± 11.3 µg m-3 for PM10, 9.80 × 10-1 ± 2.06 to 2.03 ± 8.54 × 10-1 ng m-3 for ΣPAHs, 83.9 ± 35.7 to 683 ± 521 pg m-3 for Σoxy-PAHs, 1.79 × 10-2 ± 1.23 × 10-1 to 7.12 ± 4.90 ng m-3 for Σnitro-PAHs, 83.3 ± 44.7 to 142 ± 85.9 ng m-3 for Σsaccharides, and 3.80 ± 1.54 to 5.66 ± 4.52 µg m-3 for Σions. For most species, the concentrations were higher in the dry season than in the rainy. This was related not only to the low rainfall and relative humidity characteristic of the dry season but also to an increase in fire spots recorded in the region between April and September every year from 2015 to 2018. A 4-factor solution provided the best description of the dataset, with the four identified sources of PM10 being soil resuspension (28%), biogenic emissions (27%), biomass burning (27%), and vehicle exhaust together with secondary PM (18%). Although the PM10 concentrations were not above the limit established by local legislation, the epidemiological study showed that by reducing PM2.5 concentrations to the level recommended by the WHO, approximately 35 premature deaths per 100,000 population could be avoided annually. The results revealed that biomass burning continues to be one of the main anthropic sources of emissions to the atmosphere in the region, so it needs to be incorporated into the existing guidelines and policies to reduce the concentration of particulate matter to within the limits recommended by the WHO, in order to avoid premature deaths.

Ozone precursors and boundary layer meteorology before and during a severe ozone episode in Mexico city.

Volatile organic compounds (VOCs) data in conjunction with other inorganic pollutants, surface meteorological data and continuous measurement of the Planetary Boundary Layer height (PBLH) at an urban site in Mexico City were performed from 6 to 18 March 2016. Positive Matrix Factorization (PMF) identified four emission source factors of VOCs along with equivalent black carbon (eBC), gaseous pollutants (CO, NO, NO2, SO2, NH3) and ions (Na+, Mg2+, Ca2+, NO3-, NH4+): (1) secondary aerosol precursors, (2) evaporation and non-LPG fuel combustion, (3) geogenic source and (4) vehicle exhaust. Propylene Equivalent and Maximum Incremental Reactivity (MIR) methods identified isoprene and ethylene as the highest oxidant and O3 forming species. Pollutant data normalized to the variation of the PBLH revealed continued production of O3 precursors in the afternoon beyond the typical morning rush hour. In particular this could be observed during the second part of the measurement period (12-15 March) when a strong O3 episode occurred under weak wind and lower PBLH conditions compared to the preceding period (6-11 March) when well mixed conditions due to elevated daytime PBLH and strong advection led to overall reduced pollutant mixing ratios in the afternoon hours.

A high resolution vehicular emissions inventory for Ecuador using the IVE modelling system.

Air pollutants caused by traffic has become a topic of global interest due to its impact on human health and the environment, making high-resolution emission inventories effective mechanisms for air quality management. This study proposes the development of a high-resolution inventory of vehicle emissions in Ecuador using the IVE modelling system, which was developed for its use in third world countries. The required data was collected in several provinces of the country, determining vehicle intensity, driving patterns, departure patterns, environmental variables, and vehicle technologies. To have a greater data representation, vehicles were classified into five categories according to their size, in addition three types of roads were also considered (Highways, Roads and Residential). The database was used to determine the specific power of the engine and "bines", variables that together with the emission factors are part of the calculation of IVE model. Atmospheric pollutants such as CO, VOC's and VOC Evap, NOx, SOx, PM, CO2 and CH4 were also considered, it has been identified that in Ecuador 3.66 million tons of CO were produced in 2015, with trucks representing road transportation being the largest pollutants with approximately 57.2% of the whole total. Through the spatial disaggregation it was possible to identify that the most critical areas, in terms of generation of atmospheric pollutants, are in the most densely populated cities of the country such as Quito and Guayaquil, as well as in areas near seaports and state roads, from 6:00 h, 12:00 h and 18:00 h the hours of the day in which the largest number of emissions are produced. At the end of the study, it was discovered that trucks were the ones that generated the highest emissions of atmospheric pollutants in Ecuador.

Protocol to calculate aircraft emissions for international air routes in South America.

Recently, aviation pollution has drawn important social attention. The protocol proposed in this paper can simultaneously calculate the overall emissions of six aviation pollutants (CO2, CO, HC, NOx, SO2, and PM2.5), including the landing and take-off emissions and climb/cruise/descent emissions. The international routes in South America during 2019-2021 are an example to illustrate the use of this protocol. This protocol can provide a methodological basis for calculating aviation pollutant emissions in different countries and regions. For complete details on the use and execution of this protocol, please refer to Cui et al. (2022b).1.

Particulate matter fingerprints in biofuel impacted tunnels in South America's largest metropolitan area.

This study characterized the chemical composition of particulate matter (PM) from light- (LDV) and heavy-duty (HDV) vehicles based on two traffic tunnel samplings carried out in the megacity of São Paulo (Brazil), which has >7 million vehicles and intense biofuel use. The samples were collected with high-volume samplers and analyzed using chemical characterization techniques (ion and gas chromatography, thermal-optical analysis, and inductively coupled plasma mass spectroscopy). Chemical source profiles (%) were calculated based on the measurements performed inside and outside the tunnels. Identifying a high abundance of Fe and Cu for traffic-related PM in the LDV-impacted tunnel was possible, linked with the emission of vehicles powered by ethanol and gasohol (gasoline and ethanol blend). We calculated diagnostic ratios (e.g., EC/Cu, Fe/Cu, pyrene/benzo[a]pyrene, pyrene/benzo[b]fluoranthene, and fluoranthene/benzo[b]fluoranthene) characteristic of fuel exhausts (diesel/biodiesel and ethanol/gasohol), allowing their use in the assessment of the temporal variation of the fuel type used in urban sites. Element diagnostic ratios (Cu/Sb and Fe/Cu) pointed to the predominance of LDVs exhaust-related copper and can differentiate LDVs exhaust from brake wear emissions. The carbonaceous fraction EC3 was suggested as an HDV emission tracer. A higher total polycyclic aromatic hydrocarbons (PAHs) fraction of traffic-related PM2.5 was observed in the HDV-impacted tunnel, with a predominance of diesel-related pyrene and fluoranthene, as well as higher oxy-PAHs (e.g., 9,10-anthraquinone, associated with biodiesel blends) abundances. However, carcinogenic species presented higher abundances for the LDV-impacted tunnel (e.g., benzo[a]pyrene). These findings highlighted the impact of biofuels on the characteristic ratios of chemical species and pointed to possible markers for LDVs and HDVs exhausts.

Determination of settled dust sources by analytical techniques and chemical mass balance receptor model.

The identification of sources that produce particulate atmospheric matter (PM) can be of paramount importance for the reduction of air pollution and the development of environmental policies. In order to identify the environmental impact resulting from industrial metallurgical activities in the Metropolitan Region of Vitória, ES, Brazil, it was investigated the contribution to PM that result from industrial activities and from local natural sources. For this purpose, analytical techniques were used to identify the apportionment of sources that contribute to the formation of insoluble settled dust collected at two points near the city of Vitória. Samples of soil, iron ore, limestone, coal, iron ore pellets, sinter, coke, slag, environmental samples of settled dust, and samples representative of the actual flows of materials used in an integrated steel mill were analyzed. Physicochemical characterizations, based on X-ray diffraction and 57Fe Mössbauer spectroscopy of ferruginous compounds found in sources and receptor samples, revealed the presence of highly crystallized hematite and low crystallized hematite. The latter is primarily found in soil samples, while well-crystallized hematite is found in natural samples from iron ores or after thermo-chemical processes applied during the industrial transformation of raw materials, as it happens during the production of pellets. Ferrous crystallographic forms α-FeOOH and Fe5HO8·4H2O, observed in environmental and soil samples, were also found in samples from industrial sources. Source apportionment of carbon based on the IMPROVE_A protocol for thermal/optical carbon analysis showed the participation of the elementary carbon fractions, separating contributions originated from coke and coal sources in the environmental samples. These results allowed a significant reduction of collinearity between source profiles in the application of the chemical mass balance receptor model "EPA-CMB8.2" receptor model. Consequently, it was possible to distinguish sources that process mainly ferrous and carbonaceous materials, identifying the contribution of different sources to the settled dust collected.

Caracterização da qualidade do ar atmosférico na Cidade de São Paulo para compostos do grupo BTEX (benzeno, tolueno, etilbenzeno e xilenos), utilizando amostradores passivos / Characterization of atmospheric air quality in the City of São Paulo for compounds of the BTEX group (benzene, toluene, ethylbenzene and xylenes), using passive samplers

A presença de compostos do grupo BTEX, no ar atmosférico de grandes centros urbanos como a cidade de São Paulo é proveniente principalmente de emissões veiculares e demais fontes como as industriais. A exposição a estes compostos, principalmente quando inalados, podem causar sérios efeitos adversos a saúde humana, especialmente o composto benzeno que possui propriedades cancerígenas. Desta forma, a presente pesquisa teve objetivo realizar uma caracterização da qualidade do ar atmosférico na cidade de São Paulo utilizando amostradores passivos para quantificação de compostos do grupo BTEX. Foram selecionadas 5 áreas na cidade conforme dados de tráfego destas regiões e de acordo com o perfil de uso e ocupação do solo. Adicionalmente, foi selecionada uma área como background, com interferência mínima de emissões veiculares ou industriais. Ao todo foram realizadas 3 campanhas de amostragem no entre os anos de 2020 e 2021. O período de coleta de cada campanha foi de 21 dias e na sequência as amostras foram enviadas para análise química em laboratório através do método USEPA-TO17, de 1999 com a utilização de dessorvedor térmico acoplado à um cromatógrafo de gás e um espectrômetro de massas. Foram quantificadas concentrações de BTEX em todas as áreas selecionadas, com destaque para as concentrações de benzeno cuja variação foi de 1,2µg/m3 a 13,5µg/m3, e média de 4,6µg/m3, considerando as 3 campanhas e todas as áreas. Dentro as áreas avaliadas, os pontos localizados no bairro de Santo Amaro apresentaram as maiores concentrações de BTEX, seguido dos pontos no Jaguaré, Mooca, Pinheiros e Paraíso. A campanha realizada no inverno de 2021 apresentou as maiores concentrações tendo influência das condições meteorológicas características desta estação como também influência do aumento do número de veículos circulando na cidade decorrente da diminuição do distanciamento social necessário por conta da pandemia da COVID-19. Os tratamentos estatísticos utilizados nesta pesquisa, especialmente as ferramentas PCA e PMF, concluíram que a principal contribuição para a presença dos BTEX no ar atmosférico são as emissões veiculares, principalmente para os veículos movidos a gasolina.

The presence of compounds from the BTEX group in the atmospheric air of large urban centers such as the city of São Paulo comes mainly from vehicular emissions and other sources such as industrial ones. Exposure to these compounds, especially when inhaled, can cause serious adverse effects on human health, especially the compound benzene, which has carcinogenic properties. Thus, the present research aimed to carry out a characterization of the atmospheric air quality in the city of São Paulo using passive samplers to quantify compounds of the BTEX group. Five areas were selected in the city according to traffic data from these regions and according to the profile of land use and occupation. Additionally, an area was selected as a background, with minimal interference from vehicular or industrial emissions. In all, 3 sampling campaigns were carried out between the years 2020 and 2021. The collection period of each campaign was 21 days and then the samples were sent for chemical analysis in the laboratory using the USEPA-TO17 method, from 1999 with the use of a thermal desorber coupled to a gas chromatograph and a mass spectrometer. BTEX concentrations were quantified in all selected areas, especially benzene concentrations which ranged from 1.2µg/m3 to 13.5µg/m3, and an average of 4.6µg/m3, considering the 3 campaigns and all areas. Within the evaluated areas, the points located in the Santo Amaro neighborhood had the highest concentrations of BTEX, followed by the points in Jaguaré, Mooca, Pinheiros and Paraíso. The campaign carried out in the winter of 2021 showed the highest concentrations influenced by the meteorological conditions characteristic of this season as well as the influence of the increase in the number of vehicles circulating in the city due to the decrease in the social distance necessary due to the COVID-19 pandemic. The statistical treatments used in this research, especially the PCA and PMF tools, concluded that the main contribution to the presence of BTEX in the atmospheric air are vehicular emissions, especially for gasoline-powered vehicles.

Identifying contamination of heavy metals in soils of Peruvian Amazon plain: use of multivariate statistical techniques.

The Peruvian Amazon plain has abundant natural resources and is home to great biodiversity, which makes it an area with high economic potential. However, the use of its resources through various activities has contributed to the release of heavy metals (HMs) into its soils, generating severe pollution problems which have mainly affected the health of local populations and their ecosystems. Currently, there are no comprehensive studies that have identified the specific sources of contamination by HMs in the soils of this part of the Peruvian territory. In this sense, this research aims to identify the possible sources of contamination by HMs in the soils of the Peruvian Amazon plain to focus efforts on the establishment of adequate measures for the protection of the health of people and the ecosystem. In the present study, samples of topsoils (0-20 cm depth) and subsoils (100-150 cm depth) were collected for the analysis of 11 HMs (Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn, Be, and Hg) in 48 sites located in four regions of the Peruvian Amazon plain (Loreto, Amazonas, San Martín, and Ucayali), over the year 2019. The enrichment factor and geoaccumulation index were applied to assess contamination levels of HMs. The results indicated that topsoils and subsoils presented a greater enrichment by the elements Be and Pb, and were classified as moderately contaminated. Likewise, the integral analysis of these indexes together with principal component analysis, hierarchical cluster analysis, correlation analysis, and coefficient of variation allowed the identification of potential sources of contamination by HMs. As a result, Fe, Co, Zn, Ni, V, and Cr were associated with natural or lithogenic sources (parent material, crude oil deposits, and organic matter decomposition). Hg was attributed to anthropogenic sources (illegal gold mining, atmospheric deposition, and vehicle emissions). Be, Pb, Cu, and Mn originated from natural sources (parent material, crude oil deposits, decomposition of organic matter, and forest fires) and anthropogenic (areas degraded by solid waste, illegal gold mining, agriculture, and hydrocarbons). These findings provide essential information to establish regulations and prevent and control HM contamination in soils of the Peruvian Amazon plain.

Spatio-temporal analysis of PM2.5 and policies in Northwestern South America.

This paper analyzes the spatio-temporal variations, and exceedances of the PM2.5 concentrations in Northwestern South America at different scales to assess the implemented policies and identify the involved phenomena. Through reanalysis and ground-based data, we found that high PM2.5 levels in most cities of the region are caused by wildfires and local emissions, including the capital cities of Venezuela, Ecuador, Colombia, and Panamá. In-situ measurements suggest that the majority of the cities comply with the local but not with the WHO guidelines, indicating that local annual limits should be more restrictive. Two peaks in the daily variations of PM2.5 (related to vehicle emissions) and also a steeper decrease around noon (associated with an increase in wind speed and in the boundary layer height) were identified. The trend-analysis shows that Bogotá and Medellín have a decreasing PM2.5 annual-trend (between -0.8µgm-3 and -1.7µgm-3) that corresponds to effective policies. In contrast, Cali has a positive annual-trend (0.8µgm-3) most likely because of Short-Range Transport produced by a northerly-flow from a highly polluted neighboring city, which also affects Cali's PM2.5 diurnal cycle, or by local-dynamics. The exceedances show that the policies are working on an annual but not at a daily time-scale. These results serve as a first input for additional studies, with the aim of gaining a better understanding of the contaminant before adapting current policies or implementing new policies and measures that need to include a joint international, regional, and inter-city efforts regarding pollution transport.