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1.
J Environ Sci (China) ; 87: 238-249, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791496

RESUMO

PM2.5 separator directly affects the accuracy of PM2.5 sampling. The specification testing and evaluation for PM2.5 separator is particularly important, especially under China's wide variation of terrain and climate. In this study, first a static test apparatus based on polydisperse aerosol was established and calibrated to evaluate the performance of the PM2.5 separators. A uniform mixing chamber was developed to make particles mix completely. The aerosol concentration relative standard deviations of three test points at the same horizontal chamber position were less than 0.57%, and the particle size distribution obeyed logarithmic normal distribution with an R2 of 0.996. The flow rate deviation between the measurement and the set point flow rate agreed to within ±1.0% in the range of -40 to 50°C. Secondly, the separation, flow and loading characteristics of three cyclone separators (VSCC-A, SCC-A and SCC112) were evaluated using this system. The results showed that the 50% cutoff sizes (D50) of the three cyclones were 2.48, 2.47 and 2.44 µm when worked at the manufacturer's recommended flow rates, respectively. The geometric standard deviation (GSD) of the capture efficiency of VSCC-A was 1.23, showed a slightly sharper than SCC-A (GSD =1.27), while the SCC112 did not meet the relevant indicator (GSD = 1.2 ±â€¯0.1) with a GSD = 1.44. The flow rate and loading test had a great effect on D50, while the GSD remained almost the same as before. In addition, the maintenance frequency under different air pollution conditions of the cyclones was summarized according to the loading test.


Assuntos
Filtros de Ar , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise
2.
Environ Monit Assess ; 191(12): 720, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31691038

RESUMO

We evaluated the efficiency of an air purifier using the single-chamber method for the effective removal of airborne Staphylococcus epidermidis, a nosocomial infection-causing bacterium. In this experiment, the bacterial strain S. epidermidis was injected using a nebulizer into the test chamber, which was similar to a consumer living space (60 m3). The microbial sampling was conducted via the air sampler method, and the reduction in S. epidermidis growth was monitored by performing three consecutive tests. Initially, a blank test was conducted to determine the natural decay rate and calibrate the experimental setup. After injecting the bacterial strain from 1240 to 11180 CFU per unit volume (m3), the natural decay rate showed a maximum deviation of 3.1% with a sampling error of 1.1% p at a confidence level of 95%. In addition, the particle size distribution in the test chamber was found to range from 0.3 to 5.0 µm, and a subsequent decrease in large-sized particles was observed with the operation of the air purifier, which is the size similar to that of suspended airborne bacteria. This can be used to assess the performance of the air purifier by calibrating the natural reduction value to the reduced operation value. Thus, the single-chamber technique is a promising approach for analyzing the removal efficacy of airborne bacteria from indoor air.


Assuntos
Filtros de Ar/normas , Microbiologia do Ar , Staphylococcus epidermidis/isolamento & purificação , Monitoramento Ambiental , Tamanho da Partícula
4.
Environ Pollut ; 254(Pt B): 113054, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31473392

RESUMO

Indoor air pollution is associated with numerous adverse health outcomes. Air purifiers are widely used to reduce indoor air pollutants. Ionization air purifiers are becoming increasingly popular for their low power consumption and noise, yet its health effects remain unclear. This randomized, double-blind crossover study is conducted to explore the cardiorespiratory effects of ionization air purification among 44 children in Beijing. Real or sham purification was performed in classrooms for 5 weekdays. Size-fractionated particulate matter (PM), black carbon (BC), ozone (O3), and negative air ions (NAI) were monitored, and cardiorespiratory functions were measured. Mixed-effect models were used to establish associations between exposures and health parameters. Real purification significantly decreased PM and BC, e.g. PM0.5, PM2.5, PM10 and BC were decreased by 48%, 44%, 34% and 50%, respectively. O3 levels were unchanged, while NAI was increased from 12 cm-3 to 12,997 cm-3. Real purification was associated with a 4.4% increase in forced exhaled volume in 1 s (FEV1) and a 14.7% decrease in fractional exhaled nitrogen oxide (FeNO). However, heart rate variability (HRV) was altered negatively. Interaction effects of NAI and PM were observed only on HRV, and alterations in HRV were greater with high NAI. Ionization air purifier could bring substantial respiratory benefits, however, the potential negative effects on HRV need further investigation.


Assuntos
Filtros de Ar , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/prevenção & controle , Adolescente , Ionização do Ar , Poluição do Ar/efeitos adversos , Poluição do Ar em Ambientes Fechados/análise , Pequim , Criança , Estudos Cross-Over , Método Duplo-Cego , Feminino , Frequência Cardíaca/fisiologia , Humanos , Masculino , Óxidos de Nitrogênio , Material Particulado/análise , Testes de Função Respiratória , Fuligem
5.
Ecotoxicol Environ Saf ; 183: 109559, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31408822

RESUMO

The occurrence of perfluoroalkyl substances (PFASs) was for the first time investigated in various working microenvironments (internet cafes, electronics shops, coffee shops, restaurants, etc.) in Thessaloniki, Greece, using the dust trapped by central air conditioner (A/C) filters. Perfluorooctane sulfonic acid (PFOS) was found in the range from 16 to 227 ng g-1, however it was detectable in only 30% of samples. On the contrary, perfluorohexanoic acid (PFHxA) was found in 85% of samples in the range from 3.6 to 72.5 ng g-1, while 90-95% of samples exhibited perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDcA) and perfluorododecanoic acid (PFDoDA) in the range from 10-653 ng g-1, 3.2-7.4 ng g-1 and 3.8-13.1 ng g-1, respectively. The PFAS profile varied largely among the different microenvironment categories suggesting different sources. Estimated daily intakes through dust ingestion were calculated.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Poeira/análise , Monitoramento Ambiental/métodos , Fluorcarbonetos/análise , Exposição por Inalação/análise , Ar Condicionado , Filtros de Ar , Ácidos Alcanossulfônicos/análise , Caproatos/análise , Caprilatos/análise , Ácidos Decanoicos/análise , Grécia , Ácidos Láuricos/análise
6.
Chemosphere ; 237: 124462, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31394446

RESUMO

Particulate matter and volatile organic compounds have emerged as a prime environmental concern with increasing air pollution in metropolitan cities leading to lung and heart-related issues. This paper describes a facile and novel method for fabrication of polyester based air filter via surface coating with Sericin for imparting effective removal of particulate matter and volatile organic compounds. A simple dip-coating method followed by thermal fixation has been adopted to coat Sericin on the polyester fiber. The developed changes in surface functionality and morphology of the polyester fiber were confirmed by Attenuated total reflection Fourier-transform infrared spectroscopy and Field emission scanning electron microscopy analysis. The fabricated air filter was tested for removal of particulate matter (generated burning incense stick) and volatile organic compounds (generated vaporizing gasoline), in an indoor chamber. The Sericin coated filter was able to remove the PM2.5 and PM 10 (from 1000 µg/m3 level to 5 µg/m3 in a 6.28 m3 chamber) within 27 and 23 min of operation, respectively. The fabricated filter very effectively removed particulate matter for 2160 cycles with intermittent washing. The Sericin-coated air filter also proved very effective for removal of volatile organic compounds (Benzene, Toluene, Ethylbenzene and Xylene) from an indoor chamber at a varying initial concentration of 100-1000 µg/m3. The adsorption behavior was described by Langmuir-Freundlich (sips) isotherm and pseudo-first order kinetics with minimal error. The maximum adsorption capacity (mg/g) obtained with Sips Isotherm fitting followed the order Xylene (6.97)>Ethyl Benzene (5.68)> Toluene (5.35) >Benzene (4.78).


Assuntos
Filtros de Ar , Poluição do Ar em Ambientes Fechados , Material Particulado/isolamento & purificação , Sericinas/química , Compostos Orgânicos Voláteis/isolamento & purificação , Adsorção , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/isolamento & purificação , Benzeno/análise , Benzeno/isolamento & purificação , Derivados de Benzeno/isolamento & purificação , Gasolina/análise , Microscopia Eletrônica de Varredura , Material Particulado/análise , Poliésteres/química , Espectroscopia de Infravermelho com Transformada de Fourier , Tolueno/análise , Compostos Orgânicos Voláteis/análise , Xilenos/análise , Xilenos/isolamento & purificação
7.
Environ Sci Process Impacts ; 21(8): 1403-1415, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31389929

RESUMO

Fine particulate air pollution (PM2.5) is a health hazard with numerous indoor and outdoor sources. Versatile monitors are needed to characterize PM2.5 sources, concentrations, and exposures in a range of locations and applications. Whereas low-cost light-scattering PM sensors provide real-time measurements with limited accuracy, gravimetric samples provide more accurate, albeit time-integrated, measurements. When used together, low-cost sensor data can be corrected to gravimetric samples. Here we describe the development of a portable PM2.5 monitor that features a low-cost sensor in line with an active filter sampler. Laboratory tests were conducted to determine (1) the accuracy and precision of PM2.5 concentrations derived from the filter sample and (2) correction factors for the low-cost sensor response to ammonium sulfate, Arizona road dust, urban particulate matter, and match smoke. Filter samples collected at 0.25 and 1.0 L min-1 had mean biases of -10% and -4%, relative to a tapered element oscillating microbalance, and a relative standard deviation (RSD) that ranged from 1% to 17%. The low-cost sensor correction factor varied with the test aerosol, sample flow rate, and between individual monitors. Gravimetric correction reduced the bias and RSD of ∼1 hour average concentrations measured by low-cost sensors in three collocated monitors. A week-long field experiment was also conducted to investigate how the monitor could be used to learn about sources of residential air pollution. Field data were used to identify: (1) pollution events resulting from cooking and use of a wood furnace and (2) variations in the number of air changes per hour inside the residence.


Assuntos
Filtros de Ar , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental , Habitação/normas , Material Particulado/análise , Análise Custo-Benefício , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Humanos
8.
Environ Sci Process Impacts ; 21(8): 1280-1300, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31328749

RESUMO

The House Observations of Microbial and Environmental Chemistry (HOMEChem) study is a collaborative field investigation designed to probe how everyday activities influence the emissions, chemical transformations and removal of trace gases and particles in indoor air. Sequential and layered experiments in a research house included cooking, cleaning, variable occupancy, and window-opening. This paper describes the overall design of HOMEChem and presents preliminary case studies investigating the concentrations of reactive trace gases, aerosol particles, and surface films. Cooking was a large source of VOCs, CO2, NOx, and particles. By number, cooking particles were predominantly in the ultrafine mode. Organic aerosol dominated the submicron mass, and, while variable between meals and throughout the cooking process, was dominated by components of hydrocarbon character and low oxygen content, similar to cooking oil. Air exchange in the house ensured that cooking particles were present for only short periods. During unoccupied background intervals, particle concentrations were lower indoors than outdoors. The cooling coils of the house ventilation system induced cyclic changes in water soluble gases. Even during unoccupied periods, concentrations of many organic trace gases were higher indoors than outdoors, consistent with housing materials being potential sources of these compounds to the outdoor environment. Organic material accumulated on indoor surfaces, and exhibited chemical signatures similar to indoor organic aerosol.


Assuntos
Microbiologia do Ar/normas , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental/métodos , Habitação/normas , Material Particulado/análise , Aerossóis , Ar Condicionado , Filtros de Ar , Culinária , Gases , Humanos , Tamanho da Partícula
9.
BMC Biotechnol ; 19(1): 52, 2019 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-31345193

RESUMO

BACKGROUND: Packing materials is a critical design consideration when employing biological reactor to treat malodorous gases. The acidification of packing bed usually results in a significant drop in the removal efficiency. In the present study, a biotrickling filter (BTF2) packed with plastic balls in the upper layer and with lava rocks in the bottom layer, was proposed to mitigate the acidification. RESULTS: Results showed that using combined packing materials efficiently enhanced the removal performance of BTF2 when compared with BTF1, which was packed with sole lava rocks. Removal efficiencies of more than 92.5% on four sulfur compounds were achieved in BTF2. Average pH value in its bottom packing bed was about 4.86, significantly higher than that in BTF1 (2.85). Sulfate and elemental sulfur were observed to accumulate more in BTF1 than in BTF2. Analysis of principal coordinate analysis proved that structure of microbial communities in BTF2 changed less after the shutdown but more when the initial pH value was set at 5.5. Network analysis of significant co-occurrence patterns based on the correlations between microbial taxa revealed that BTF2 harbored more diverse microorganisms involving in the bio-oxidation of sulfur compounds and had more complex interactions between microbial species. CONCLUSIONS: Results confirmed that using combined packing materials effectively improved conditions for the growth of microorganisms. The robustness of reactor against acidification, adverse temperature and gas supply shutdown was greatly enhanced. These provided a theoretical basis for using mixed packing materials to improve removal performance.


Assuntos
Filtros de Ar/microbiologia , Reatores Biológicos/microbiologia , Microbiota , Compostos de Enxofre/isolamento & purificação , Compostos de Enxofre/metabolismo , Poluentes Atmosféricos/isolamento & purificação , Poluentes Atmosféricos/metabolismo , Biodegradação Ambiental , Filtração/instrumentação , Filtração/métodos , Oxirredução
10.
Environ Pollut ; 253: 181-189, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31306825

RESUMO

This work explores the use of Raman micro-spectroscopy to determine sources of airborne particulate matter collected on PM2.5 air filters in Imperial Valley, California. The goal is to examine if nearby soil is a potential source of particles sampled on air filters deployed in an urbanized desert area during events of unusually high PM2.5 excursions. Particle specific composition information can be an indicator of potential origin. This can provide insights into the source of unexpectedly high proportion of large particles sampled on PM2.5 filters in the vicinity of Imperial Valley. The measured spectral correspondence between the filter and soil particles, in the size range of 2.5-10 µm, is consistent with windblown dust being a likely source of the larger (>2.5 µm) particles collected on the PM2.5 filters. Additionally, these particles were identified as components of commonly occurring crustal minerals in the vicinity of the sampling site, such as iron oxides, hydroxides, sulfides, titanium dioxides and aluminosilicates. A substantial portion of the analyzed filter particles displayed a strong broadband fluorescence signal, which is consistent with the presence of organic matter and has been recognized as a marker for soil related origin of the filter particles. Elemental carbon (soot) was found to be prevalent among the particles as well, suggesting the existence of combustion related sources. Comparison between a heavily loaded filter sample and a filter with a more typical, lower loading did not show any obvious difference in chemical compositions. In both cases the particles appeared to be of crustal origin with the prevalence of elemental carbon. The primary difference between these two filter samples appear to be their particle size distribution - the heavily loaded filter sample contained greater proportion of large particles (>2.5 µm), and was more consistent with spectral signature of soils analyzed from the region.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Solo , Filtros de Ar , Poluição do Ar/análise , Poluição do Ar/estatística & dados numéricos , California , Carbono/análise , Poeira/análise , Tamanho da Partícula , Análise Espectral
11.
Environ Pollut ; 253: 190-198, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31310869

RESUMO

Increased public awareness of the health impacts of atmospheric fine particulate matter (PM2.5) has led to increased demand and deployment of indoor air cleaners. Yet, questions still remain about the effectiveness of indoor air cleaners on indoor PM2.5 concentrations and personal exposure to potentially hazardous components of PM2.5. Metals in PM2.5 have been associated with adverse health outcomes, so knowledge of their sources in urban indoor and outdoor areas and how exposures are influenced by indoor air cleaners would be beneficial for public health interventions. We collected 48-h indoor, outdoor, and personal PM2.5 exposure samples for 43 homes with asthmatic children in suburban Shanghai, China during the spring months. Two sets of samples were collected for each household, one set with a functioning air filter placed in the bedroom ("true filtration") and the other with a non-functioning ("sham") air cleaner. PM2.5 samples were analyzed for elements, elemental carbon, and organic carbon. The major sources of metals in PM2.5 were determined by Positive Matrix Factorization (PMF) to be regional aerosol, resuspended dust, residual oil combustion, roadway emissions, alloy steel abrasion, and a lanthanum (La) and cerium (Ce) source. Under true filtration, the median indoor to outdoor percent removal across all elements increased from 31% to 78% and from 46% to 88% across all sources. Our findings suggest that indoor air cleaners are an effective strategy for reducing indoor concentrations of PM2.5 metals from most sources, which could translate into improved health outcomes for some populations.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Exposição Ambiental/análise , Metais/análise , Aerossóis , Filtros de Ar , Poluição do Ar em Ambientes Fechados/análise , Criança , China , Poeira , Monitoramento Ambiental , Filtração , Humanos , Material Particulado/análise , Estações do Ano
12.
Artigo em Inglês | MEDLINE | ID: mdl-31167357

RESUMO

Filtering nonwovens loaded with activated carbon are among the most popular materials used in the construction of filtering facepiece respirators (FFRs) with anti-odour properties that can be used for respiratory protection at workplaces where the occupational exposure limits of harmful substances are not exceeded. Such FFRs, in addition to a polymer filter material of varying effectiveness, also contain a layer of activated-carbon-loaded nonwoven filter, which limits the quantity of chemical compounds entering the breathing zone. The aim of this work was to analyse the influence of challenge concentration (20-120 ppm), relative humidity (2-70%), flow rate (20-55 L/min), and flow pattern (steady-state and pulsating) on the breakthrough of polymer/carbon nonwovens. A commercial activated-carbon-loaded nonwoven filter was used in this study. Its morphology and textural parameters were determined using optical microscopy, image processing, and nitrogen adsorption/desorption measurements at 77 K. Breakthrough experiments were carried out using cyclohexane vapours to assess adsorption characteristics of polymer/carbon media. The results showed that the breakthrough times decreased with increasing challenge concentration (up to 30%), relative humidity (up to 73%), and flow rate (up to 72%). The pulsating flow pattern was found to be more favourable in terms of odour reduction efficiency (up to 30%). The results indicate that all of these factors should be considered during selection and performance assessment of respirators used for odour relief.


Assuntos
Adsorção , Filtros de Ar , Carvão Vegetal/química , Dispositivos de Proteção Respiratória , Poluentes Ocupacionais do Ar , Filtração , Humanos , Umidade , Processamento de Imagem Assistida por Computador/métodos , Microscopia , Exposição Ocupacional/análise , Local de Trabalho
13.
Artigo em Inglês | MEDLINE | ID: mdl-31163683

RESUMO

Carbonyl compounds (CCs) are products present both as vapors and as condensed species adsorbed on the carbonaceous particle matter dispersed in the air of urban areas, due to vehicular traffic and human activities. Chronic exposure to CCs is a potential health risk given the toxicity of these chemicals. The present study reports on the measurement of the concentrations of 14 CCs in air as vapors and 2.5 µm fraction PM by the ENVINT GAS08/16 gas/aerosol sampler, a serial sampler that uses annular denuder, as sampling device. The 14 CCs were derivatized during sampling prior to gas-chromatographic separation and multiple detection by mass spectrometry, nitrogen-phosphorus thermionic, electron capture detection. Outdoor air multiple samples were collected in four locations in the urban area of Florence. The results evidenced that formaldehyde, acetaldehyde, and acetone were the more abundant CCs in the studied areas. The data collected was discussed considering the particle to vapor ratio of each CC found. The CCs pollution picture obtained was tentatively related to the nature and intensity of the traffic transiting by the sampling sites. This approach allowed to determine 14 CCs in both concentrated and diluted samples and is proposed as a tool for investigating outdoor and indoor pollution.


Assuntos
Filtros de Ar , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Aldeídos/análise , Cromatografia Gasosa , Monitoramento Ambiental/métodos , Acetona/análise , Adsorção , Itália , Material Particulado/química
14.
Artigo em Chinês | MEDLINE | ID: mdl-31177712

RESUMO

Objective: To effectively reduce the concentration of poisons in cleanroom, protect the health of workers, realize the optimization and automatic control of the new return air device. And the influence of initial concentration, air volume, temperature and relative humidity of formaldehyde on the purification effect of the new return air device was explored. Methods: The purification effect of the new return air device installed with the activated carbon and the photocatalyst purification net or ordinary activated carbon purification network was tested in a 60 m(3) simulated cleanroom. The concentration of formaldehyde was determined by solution absorption-phenol reagent spectrophotometry. Based on the single factor experiment to determine the combination of two purification nets. The effects of air volume, initial formaldehyde concentration, temperature and relative humidity on the purification effect of the new return air device were investigated by orthogonal test. Then, the performance parameters of the return air device to purify formaldehyde were determined. Results: The formaldehyde purification efficiency of the two types of purification nets in the new return air device was higher than that of the ordinary activated carbon purification network (P<0.05) . The combination of activated carbon and photocatalyst purification net has no effect on the formaldehyde purification efficiency of the return air device (P>0.05) . According to the direct analysis and variance analysis, air volume was the most sensitive factor (F value is 18.894, P<0.05) , followed by initial concentration (F value is 16.128, P<0.05) , while temperature and relative humidity have little effect (F value is 0.041 and 0.599, respectively, P>0.05) . LSD analysis showed that there was no significant difference in the purification efficiency of formaldehyde between 475 m(3)/h and 626 m(3)/h (P>0.05) . From the perspective of formaldehyde purification efficiency and energy saving, when the air volume is set to 475 m(3)/h, the new return air device has higher purification efficiency for high concentration of formaldehyde. Conclusion: The new return air device consisting of activated carbon and photocatalyst purification net can play a good purification role in cleanroom with different temperatures and different humidity. Its formaldehyde purification efficiency is affected by air volume and initial concentration.


Assuntos
Filtros de Ar , Poluição do Ar em Ambientes Fechados , Formaldeído , Poluição do Ar em Ambientes Fechados/prevenção & controle , Carvão Vegetal , Humanos , Temperatura Ambiente
15.
Bull Environ Contam Toxicol ; 103(1): 155-162, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31250069

RESUMO

This study summarized existing adsorption technologies for the removal of elemental mercury in the flue gas. Both carriers (e.g., active carbon (AC), pyrolyzed char, inorganic adsorbents and fly ash) and various modification methods (pore structure improvement, oxygen-containing functional groups addition and new active reagents impregnation) were compared to shed light on the development of future adsorption technology. AC and char possibly performed more mercury adsorption capacity (MAC) compared with fly ash and inorganic adsorbents since carbon atom existence was easier to form the active halogen groups (C-X) and oxygen containing groups. Though both pore structure improvement and chemical group formation improved the MAC of adsorbents, the chemical modification methods (oxygen-containing functional groups addition and new active reagents impregnation) were more effective. The impregnation of halogen, sulfur and metal chloride could distinctly form lots of active sites on the adsorbents and developed high effective mercury adsorbents. In the future, the adsorption researches possibly focus on SO2 and H2O resistance of adsorbents, separable adsorbents, low-cost chemical modification methods, and utilization potential of fly ash.


Assuntos
Poluição do Ar/prevenção & controle , Mercúrio/análise , Adsorção , Filtros de Ar , Poluição do Ar/análise , Poluição do Ar/estatística & dados numéricos , Carbono/química , Carvão Vegetal/química , Cinza de Carvão/química , Oxigênio , Enxofre/química
16.
Environ Sci Pollut Res Int ; 26(23): 24262-24271, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31228070

RESUMO

Modern lifestyle with the increasing use of air conditioner (AC) has been linked with breathing difficulties, irritation, dryness, and other symptoms. Hence, dust mites were isolated from AC filters, which causes allergic diseases. A total of 95 dust samples were collected from AC filters from hospitals, guest house, office, school, and homes in Chandigarh, India. The highest concentration of dust mites was detected from hospitals (9/g), offices (7/g), households (6/g), guest houses (3/g), and schools (0/g). Based on the morphology of dust mites observed under a light microscope, Dermatophagoides and Acarus species were found most common. Indoor air quality was also monitored to find out their relation with dust mites present in AC filters. Further, the respiratory health status of indoor facility users was also assessed using a standard questionnaire as a study tool. It was seen that 55.3% of male among the total respondents were having an allergy and only 44.7% of the females had an allergy. The allergy among the male respondents (55.3%) was significantly more (p < 0.05) in comparison with female respondents (44.7%). Some of the respondents also reported a family history of rhinitis (31.9%), asthma (12.8%), recurrent urticaria (6.4%), and conjunctivitis (6.4%). Interestingly, 23.4% of study participants reported that they get disturbed by the use of AC and house dust was found to be the most triggering factor in enhancing the symptoms of allergy. Thus, it is recommended that air conditioner filters should be cleaned regularly to prevent the accumulation of the dust mites and related allergens on filter dust.


Assuntos
Ar Condicionado , Filtros de Ar , Poluição do Ar em Ambientes Fechados/análise , Alérgenos/análise , Ácaros/crescimento & desenvolvimento , Animais , Antígenos de Dermatophagoides , Asma/etiologia , Poeira/análise , Feminino , Humanos , Índia , Masculino
17.
Environ Sci Process Impacts ; 21(8): 1353-1363, 2019 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-31070628

RESUMO

With regard to the application of semi-volatile organic compounds (SVOCs) in products for indoor use, a distinct trend towards substitutions can currently be observed. Among the possible phthalate alternatives, in particular the adipic acid esters have gained in market importance. The chemical-physical and thermodynamic properties of the phthalates and adipates allow the conclusion to be drawn that they are distributed between different compartments (gas phase, particle phase, dust, material surfaces) of the indoor space. There are, however, hardly any data in existence which were collected in a real environment over six months and longer. Diisobutyl adipate (DiBA), di-n-butyl adipate (DnBA), dipentyl phthalate (DPP), butyl benzyl phthalate (BBzP) and di-2-ethylhexyl adipate (DEHA) were selected as model substances. By means of spiked latex paint and spiked house dust, these SVOCs were introduced into two identically equipped test rooms. One room was cleaned regularly, whilst the reference room was not entered for a 133 day experimental period. The concentrations of the five target substances were determined in the air and in material samples (carpet, vacuum-cleaner bags, filters). During the operation of an air purifier, the air concentration of the target substances in a room could be reduced by more than 50%. In the reference room, a correlation between the logarithmic air concentration and the reciprocal room temperature was found. The results show with great clarity the complexity of the conditions in an indoor room. Models can therefore depict the exposure as a statistical average but not, however, describe the individual case.


Assuntos
Filtros de Ar , Poluição do Ar em Ambientes Fechados/análise , Poluição do Ar em Ambientes Fechados/prevenção & controle , Poeira/análise , Modelos Teóricos , Compostos Orgânicos Voláteis/análise , Adipatos/análise , Humanos , Ácidos Ftálicos/análise
18.
Chemosphere ; 231: 256-268, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31129407

RESUMO

Air pollution in China is an ongoing concern, with subsets of the population (e.g., asthmatic children) especially susceptible to the associated health effects. In addition, people spend the majority of their time indoors, where pollutant composition may differ from the better characterized ambient environment. Although volatile organic compounds (VOCs) present health risks and have high concentrations indoors, their sources have not been thoroughly quantified in typical homes in suburban China. Similarly lacking is an understanding of how well a purifier with high efficiency particulate air and activated carbon filters can remove VOCs in a real-world setting in China. In this study, we a) quantified total VOCs (TVOC) and 900 + individual VOCs in 20 homes in China, b) identified potential sources of VOCs, and c) evaluated impacts of filtration. We used non-negative matrix factorization, a variable reduction technique, to identify sources. TVOC and individual compounds had higher concentrations indoors than outdoors (mean [range] indoors, filtration with pre-filter only: 302 [56-793] µg m-3; outdoors, entire study: 92 [26-629] µg m-3), indicating prevalent sources indoors. Many compounds detected have not, to our knowledge, been measured in homes in China. Some compounds (e.g., octanal, heptanal, ⍺-cedrene) were specific to the indoor environment, a few were ubiquitous (e.g., acetaldehyde, formaldehyde), and others were detected infrequently. These compounds may originate from consumer products, solvents, vehicle emissions, a hexane source, wooden products, and cooking. Filtration may improve air quality indoors by lowering concentrations of some VOCs, and, specifically, contributions related to solvents and consumer products.


Assuntos
Filtros de Ar , Poluentes Atmosféricos/análise , Poluição do Ar em Ambientes Fechados/análise , Monitoramento Ambiental , Compostos Orgânicos Voláteis/análise , Poluição do Ar/estatística & dados numéricos , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , Aldeídos , Asma , China , Culinária , Formaldeído/análise , Humanos , Emissões de Veículos
19.
Environ Sci Pollut Res Int ; 26(21): 21511-21523, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31127522

RESUMO

Radionuclides 137Cs and 90Sr and total beta activity were determined from air filters collected in Rovaniemi (Finnish Lapland) in 1965-2011. Nuclear contamination sources present in the air filter samples as well as temporal changes in radionuclide concentrations were examined. Ozone observations and meteorological modeling were used in combination with radionuclide analyses to study the reasons behind the observed seasonal concentration variation. In general, the magnitude and variation in activity concentrations of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965-2011 corresponded well with values from other countries. However, the obtained results prove in practice that hardly any refractory or intermediate radionuclides from the destroyed Chernobyl reactor fuel were introduced to Finnish Lapland. The main source of 137Cs and 90Sr and total beta activity in the surface air of Rovaniemi in 1965-2011 has been intense atmospheric nuclear weapon testing in 1950s-1960s and later tests performed in 1965-1980, as well as leakages from underground nuclear tests in Semipalatinsk, 1966, and Novaya Zemlya, 1987. For 137Cs and total beta activity, the influence of Chernobyl and Fukushima accidents was detected.


Assuntos
Poluentes Radioativos do Ar/análise , Radioisótopos de Césio/análise , Monitoramento de Radiação , Radioisótopos de Estrôncio/análise , Filtros de Ar , Acidente Nuclear de Chernobyl , Finlândia , Acidente Nuclear de Fukushima
20.
Nat Commun ; 10(1): 2177, 2019 05 16.
Artigo em Inglês | MEDLINE | ID: mdl-31097709

RESUMO

Air filtration has become an essential need for passive pollution control. However, most of the commercial air purifiers rely on dense fibrous filters, which have good particulate matter (PM) removal capability but poor biocidal effect. Here we present the photocatalytic bactericidal properties of a series of metal-organic frameworks (MOFs) and their potentials in air pollution control and personal protection. Specifically, a zinc-imidazolate MOF (ZIF-8) exhibits almost complete inactivation of Escherichia coli (E. coli) (>99.9999% inactivation efficiency) in saline within 2 h of simulated solar irradiation. Mechanistic studies indicate that photoelectrons trapped at Zn+ centers within ZIF-8 via ligand to metal charge transfer (LMCT) are responsible for oxygen-reduction related reactive oxygen species (ROS) production, which is the dominant disinfection mechanism. Air filters fabricated from ZIF-8 show remarkable performance for integrated pollution control, with >99.99% photocatalytic killing efficiency against airborne bacteria in 30 min and 97% PM removal. This work may shed light on designing new porous solids with photocatalytic antibiotic capability for public health protection.


Assuntos
Filtros de Ar , Desinfecção/métodos , Escherichia coli/efeitos dos fármacos , Estruturas Metalorgânicas/farmacologia , Microbiologia do Ar , Catálise/efeitos da radiação , Imidazóis/química , Imidazóis/farmacologia , Luz , Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/efeitos da radiação , Testes de Sensibilidade Microbiana , Oxigênio/metabolismo , Porosidade , Espécies Reativas de Oxigênio/farmacologia , Difração de Raios X , Zinco/química , Zinco/farmacologia
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