Microscopic morphology and elemental composition of atmospheric particles from seven micro-environments in Xi’an:
19 Mar 2019-Indoor and Built Environment (SAGE PublicationsSage UK: London, England)-Vol. 28, Iss: 9, pp 1237-1253
TL;DR: In this article, the morphological and elemental compositions of individual particles in seven micro-environments of Xi'an were characterized using a morphological-and elemental-based approach.
Abstract: This paper characterizes the morphological and elemental compositions of individual particles in seven micro-environments of Xi’an. Atmospheric particulate matter samples were collected at one subu...
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TL;DR: In this article, a literature review of the effects of traffic-related pollution around schools on student health and mitigation measures was conducted, and a simple meta-analysis on the effect of PM2.5 and PM10 on respiratory health was also performed.
Abstract: Introduction The impact of traffic-related pollution around schools on student health has attracted increased attention in recent years. As students are exposed to pollutants around schools during their daily commute, the effect of pollutant exposure on students is substantial. Methods A literature review of the effects of traffic-related pollution around schools on student health and mitigation measures was conducted. A simple meta-analysis on the effects of PM2.5 and PM10 on respiratory health was also performed. Results Traffic-related pollutants have a great impact on student health. For example, NO2, elemental carbon, and particulate matter have a significant impact on the cognition and developmental nervous systems and respiratory system of students. When concentrations are high, the prevalence of respiratory infection, asthma, tracheitis, and other diseases in children increases. Traffic-related pollutants around schools affect the cardiovascular system and are associated with allergic symptoms. To reduce the effect of traffic-related pollution on student health, some mitigation measures are suggested. Suitable transport routes and walking routes to and from school should be planned based on the pollution levels around the school. Trees and hedges could be set up on the roads around the school to prevent the diffusion of PM. The influence of street form and building layout on pollutant diffusion should be considered in urban planning. In heavily polluted areas, pollutant filters can be used to clean the air. The government should actively reduce the number of vehicles near schools, strengthen infrastructure construction, and reduce congestion. At the social level, idle running time should be reduced. Conclusions We have a relatively strong understanding of the traffic pollution around schools and its impact on student health. The mitigation measures for reducing the effect of traffic pollution on student health were summarized. Future government policies and social initiatives that could be taken were proposed.
16 citations
TL;DR: In this paper, the physicochemical characteristics of the particulate matter ≤ 10 µm (PM10) at both congested and non-congested areas of Lahore, the second largest city of Pakistan were assessed.
Abstract: This study aims to assess the physicochemical characteristics of the particulate matter ≤10 µm (PM10) at both congested and non-congested areas of Lahore, the second-largest city of Pakistan. PM10 ...
6 citations
15 Oct 2020
TL;DR: In this paper, the authors discuss the role of airborne biological aerosols in the atmosphere-biosphere interface and how they significantly impact the environment and Earth's climate, including primary biological particles such as fungal spores.
Abstract: Airborne biological aerosols are an integral part of the atmosphere–biosphere interface and significantly impact the environment and Earth’s climate. Primary biological particles such as fungal spo...
4 citations
TL;DR: In this paper, a parallel evaluation of indoor/outdoor atmospheric corrosion of steel, pollutants, and electric boxes is presented, which is important for the reliability of electric and electronic instruments.
Abstract: Indoor corrosion inside electric boxes is important for the reliability of electric and electronic instruments. A parallel evaluation of indoor/outdoor atmospheric corrosion of steel, pollutants an...
3 citations
Journal Article•
TL;DR: The average PM2.5 mass concentration in 4 years was 183.8±104.2 μg/m3 with an increasing trend as mentioned in this paper, which indicated that wet deposition efficiently removed aerosols resulting in low PM 2.5 level.
Abstract: Daily PM2.5(particle size smaller than 2.5 μm) samples were collected in Xi'an from September,2003 to July,2007,synchronously during that period,meteorological data(temperature,wind speed,rainfall and visibility) and air pollution index(API) were obtained.The average PM2.5 mass concentration in 4 years was 183.8±104.2 μg/m3 with an increasing trend.Weekly variation of PM2.5 concentrations showed two peaks corresponding to the busy traffic hours.Seasonal variations of PM2.5,which were circulative in annual scale,exhibited a same decreasing order as follows:winterautumnspringsummer.The temporal series of PM2.5,meteorological parameters,visibility,and air pollution index,API,indicated that wet deposition efficiently removed aerosols resulting in low PM2.5 level.The wind speed could lead to dilute PM levels when it was above 2.25 m/s.In contrast,lower wind speed most likely contributed to high PM levels.PM2.5 had a moderate positive relationship with API and a moderate negative relationship with visibility.
3 citations
References
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Book•
01 Jan 1987
TL;DR: SEM-Instrumentation: Introduction Principles of Operation Specimen/Electron Interactions Detectors Operating Conditions and Limitations Specimen Preparation: Specimen Characteristics Drying Techniques Coating Cryo-SEM SEM X-Ray Microanalysis Instrumentation as mentioned in this paper.
Abstract: SEM-Instrumentation: Introduction Principles of Operation Specimen/Electron Interactions Detectors Operating Conditions and Limitations Specimen Preparation: Specimen Characteristics Drying Techniques Coating Cryo-SEM SEM X-Ray Microanalysis-Instrumentation: Introduction X-Ray Production in the SEM Wavelength Dispersive Systems (WDS) Energy Dispersive Systems (EDX) Operating Conditions and Limitations Data Handling Other Surface Analytical Techniques.
2,084 citations
TL;DR: In this paper, a global three-dimensional model of the troposphere is used to simulate the sources, abundances, and sinks of mineral aerosol and the species involved in the photochemical oxidant, nitrogen, and sulfur cycles.
Abstract: A global three-dimensional model of the troposphere is used to simulate the sources, abundances, and sinks of mineral aerosol and the species involved in the photochemical oxidant, nitrogen, and sulfur cycles. Although the calculated heterogeneous removal rates on mineral aerosol are highly uncertain, mainly due to poorly known heterogeneous reaction rates, the reaction of SO2 on calcium-rich mineral aerosol is likely to play an important role downwind of arid source regions. This is especially important for regions in Asia, which are important and increasing emitters of sulfur compounds. Our results indicate that the assumption that sulfate aerosol follows an accumulation mode size distribution, is particularly in Asia likely to overestimate the sulfate aerosol climate-cooling effect. An even larger fraction of gas phase nitric acid may be associated with and neutralized by mineral aerosol. Interactions of N2O5, O3, and HO2-radicals with dust are calculated to affect the photochemical oxidant cycle, causing ozone decreases up to 10% in and nearby the dust source areas. Comparison of these results with limited available measurements indicates that the proposed reactions can indeed take place, although due to a lack of measurements a rigorous evaluation is not possible at this time.
1,053 citations
TL;DR: In this article, continuous measurements of atmospheric organic and elemental carbon (OC and EC) were taken during the high-pollution fall and winter seasons at Xi'an, Shaanxi Province, China from September 2003 through February 2004.
Abstract: . Continuous measurements of atmospheric organic and elemental carbon (OC and EC) were taken during the high-pollution fall and winter seasons at Xi'an, Shaanxi Province, China from September 2003 through February 2004. Battery-powered mini-volume samplers collected PM2.5 samples daily and PM10 samples every third day. Samples were also obtained from the plumes of residential coal combustion, motor-vehicle exhaust, and biomass burning sources. These samples were analyzed for OC/EC by thermal/optical reflectance (TOR) following the Interagency Monitoring of Protected Visual Environments (IMPROVE) protocol. OC and EC levels at Xi'an are higher than most urban cities in Asia. Average PM2.5 OC concentrations in fall and winter were 34.1±18.0 μg m−3 and 61.9±;33.2 μg m−3, respectively; while EC concentrations were 11.3±6.9 μg m−3 and 12.3±5.3 μg m−3, respectively. Most of the OC and EC were in the PM2.5 fraction. OC was strongly correlated (R>0.95) with EC in the autumn and moderately correlated (R=0.81) with EC during winter. Carbonaceous aerosol (OC×1.6+EC) accounted for 48.8%±10.1% of the PM2.5 mass during fall and 45.9±7.5% during winter. The average OC/EC ratio was 3.3 in fall and 5.1 in winter, with individual OC/EC ratios nearly always exceeding 2.0. The higher wintertime OC/EC corresponded to increased residential coal combustion for heating. Total carbon (TC) was associated with source contributions using absolute principal component analysis (APCA) with eight thermally-derived carbon fractions. During fall, 73% of TC was attributed to gasoline engine exhaust, 23% to diesel exhaust, and 4% to biomass burning. During winter, 44% of TC was attributed to gasoline engine exhaust, 44% to coal burning, 9% to biomass burning, and 3% to diesel engine exhaust.
531 citations
TL;DR: In this article, the hygroscopic properties of freshly produced carbon and diesel soot particles at subsaturations (i.e. at relative humidity < 100%) were investigated. And the results showed that freshly emitted combustion particles are unlikely to act as cloud condensation nuclei whereas an aging of the particles will enhance their nucleation ability.
493 citations
TL;DR: In this article, the morphology and chemical composition of individual airborne particles were determined by scanning electron microscopy, and image analysis was employed to study the number-size distributions of particles.
201 citations