PSCF method for source identification of particulate matter in an agricultural background region in Brazil.

The use of mathematical and statistical models to investigate potential sources of pollutants that have been transported by air masses to a study site is important for establishing control and monitoring measures for air pollutants such as PM10 and PM2.5. During the study period, from 2018 to 2021, the concentrations of PM10 and PM2.5 recorded in Ribeirão Preto (SP, Brazil) were higher during spring and winter, with a tendency to increase the amplitude and its maximum values relative to daily averages. The source-receptor model, Potential Source Contribution Function (PSCF), was used to identify probable sources of these pollutants, and the regions known as Triângulo Mineiro and Intermediate Geographic Region of Juiz de Fora (MG, Brazil) were the main regions associated with high PSCF probability values (> 0.5) as sources of PM. These regions indicate that the possible sources of PM emissions are associated with industrial complexes and agriculture, especially coffee production.

Occurrence of polar organic compounds in atmospheric particulate matter: a system review in South America.

Particulate matter (PM) is one of the existing air pollutants, which can cause damages to human health, public property, and the environment. The chemical composition of this pollutant greatly varies, mainly its organic fraction. Thus, our objective was to carry out a literature review based on articles, considering studies conducted in South America, whose authors address the characterization of the polar organic fraction of PM. We performed the review using the Scopus, SciELO, and Web of Science databases, considering publications dated from the years 2010 to 2019. A total of 14,575 articles were found, of which only 12 met the predefined selection criteria. According to our research, the most studied compound is levoglucosan, a biomass burning marker belonging to the group of anhydrous sugars. Besides, nitro-PAHs, which usually originate from vehicular sources and are compounds with mutagenic and carcinogenic characteristics, have also been found. Moreover, we concluded that, currently, there are few studies on the subject in South America, requiring more research on polar organic compounds present in PM in countries of this region. These studies are of great importance because some compounds can cause great damage to human health, such as the nitro-PAHs; furthermore, PM may still have unknown compounds that need identification and elucidation of their toxicity.

A review of multivariate analysis: is there a relationship between airborne particulate matter and meteorological variables?

Among statistical tools for the study of atmospheric pollutants, trajectory regression analysis (TRA), cluster analysis (CA), and principal component analysis (PCA) can be highlighted. Therefore, this article presents a systematic review of such techniques based on (i) air mass influences on particulate matter (PM) and (ii) the study of the relationship between PM and meteorological variables. This article aims to review studies that use TRA and to review studies that adopt CA and/or PCA to identify the associations and relationship between meteorological variables and atmospheric pollutants. Papers published between 2006 and 2018 and indexed by five of the main scientific databases were considered (ScienceDirect, Web of Science, PubMed, SciELO, and Scopus databases). PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) recommendations supported this systematic review. From the resulting most relevant papers, eight studies analyzed the influence of air mass trajectories on PM using TRA and twenty-one studies searched for the relationship between meteorological variables and PM using CA and/or PCA. A combination of TRA and time series models was identified as the possibility of future works. Besides, studies that simultaneously combine the three techniques to identify both the influence of air masses on PM and its relationship with meteorological variables are a possibility of future papers, because it can lead to a better comprehension of such a phenomenon.

Source apportionment of metallic elements in urban atmospheric particulate matter and assessment of its water-soluble fraction toxicity.

Clean air is essential for the maintenance of human life and environmental balance. The atmospheric particulate matter (PM) is one of the main air pollutants and is characterized by the heterogeneity of its composition, being able to accumulate numerous components, such as metallic elements, which contribute to increasing its toxicity. The objectives of this study were to assess of the air quality in two urban environments, to carry out the source apportionment of the metallic elements Al, Ba, Cd, Pb, Cu, Cr, Fe, Mn, Ni, and Zn in the PM2.5 and PM2.5-10, and evaluate the toxicity of PM2.5 and PM2.5-10 water-soluble fractions using Lactuca sativa as bioindicator. The collection of PM2.5 and PM2.5-10 was performed using a dichotomous stacked filter unit (SFU) sampler. The source apportionment was carried out using the EPA PMF 5.0 receptor model and the toxicity tests followed the EPA Ecological Effects Test Guidelines OPPTS 850.4200: Seed Germination/Root Elongation Toxicity Test. The source apportionment demonstrated that vehicular and industrial emissions are the main anthropogenic sources contributing to the concentration of metallic elements to thePM2.5 and PM2.5-10. The studied sites did not show statistically significant differences in terms of phytotoxicity to the Lactuca sativa seeds. Cd and Cu were identified as the main metallic elements which able to cause negative effects on seed germination and root elongation, respectively. The presence of cadmium and copper in the atmospheric particulate matter is one of the main causes of the phytotoxicity affecting the Lactuca sativa seed germination and root elongation.

Análise da eficiência energética, ambiental e econômica entre lâmpadas de LED e convencionais / Analysis of energy efficiency, environmental and economical between LED and conventional lamps

RESUMO Os Diodos Emissores de Luz, mais conhecidos como LED's, são componentes eletrônicos semicondutores que conseguem transformar a energia elétrica em luz, diferente das lâmpadas convencionais. O LED é um componente bipolar, que quando passa corrente elétrica, a luz é gerada. As lâmpadas modernas utilizam LED em sua formação, as quais liberam menos calor e utilizam menos energia, sendo assim mais econômicas que as incandescentes e as fluorescentes. Além de apresentarem maior durabilidade que as demais, as lâmpadas LED não promovem o aquecimento dos ambientes internos e seu descarte tem reduzido impacto ambiental. A associação de vantagens ambientais e econômicas torna esta tecnologia atrativa ao consumidor, embora o custo para sua aquisição seja superior aos demais modelos de lâmpadas disponíveis no mercado. Neste estudo foram realizados testes de verificação do fluxo luminoso e eficiência energética, além de análise ambiental das lâmpadas domésticas. Os resultados obtidos comprovaram o potencial da tecnologia LED em relação às demais lâmpadas analisadas, especialmente quanto à questão econômica e ambiental conforme estudos prévios analisados.

ABSTRACT Light Emitter Diode, more commonly known as LED´s, are semiconductor electronic components that can transform electrical energy into light, unlike conventional lamps. LED has a bipolar component, when polarized, allows the passage of electric current creating light. Modern lamps use LED in their formation, which release less heat, use less energy, and are more economic than incandescent and fluorescent. Besides present more durability than the others, LED lamps do not heat up the environment and their disposals do not attack the environment. The association of environmental and economic advantages makes this technology attractive to consumer, although the cost of acquisition is higher than the other lamps models available in market. The verification of luminous flux and energy efficiency tests were realized in this study, beyond an environmental analysis. The obtained results proved the potential of LED technology due to other analyzed lamps, especially economic and environmental issue as previous studies analyzed.