scholarly journals Diurnal variation of ionic aerosol species and water-soluble gas concentrations at a high-elevation site in the Japanese Alps

2001 ◽  
Vol 106 (D15) ◽  
pp. 17335-17345 ◽  
Author(s):  
Mizuka Kido ◽  
Kazuo Osada ◽  
Katsuji Matsunaga ◽  
Yasunobu Iwasaka
Keyword(s):  
Diurnal Variation ◽  
High Elevation ◽  
Water Soluble ◽  
High Elevation Site

scholarly journals Seasonal variations in PM10 inorganic composition in the Andean city

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rasa Zalakeviciute ◽  
Katiuska Alexandrino ◽  
Yves Rybarczyk ◽  
Alexis Debut ◽  
Karla Vizuete ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Inductively Coupled Plasma ◽  
Chemical Elements ◽  
Large Fraction ◽  
Urban Pollution ◽  
Optical Emission ◽  
High Elevation ◽  
Water Soluble ◽  
Wet Season ◽  
Soluble Ions

Abstract Particulate matter (PM) is one of the key pollutants causing health risks worldwide. While the preoccupation for increased concentrations of these particles mainly depends on their sources and thus chemical composition, some regions are yet not well investigated. In this work the composition of chemical elements of atmospheric PM10 (particles with aerodynamic diameters ≤ 10 µm), collected at the urban and suburban sites in high elevation tropical city, were chemically analysed during the dry and wet seasons of 2017–2018. A large fraction (~ 68%) of PM10 composition in Quito, Ecuador is accounted for by water-soluble ions and 16 elements analysed using UV/VIS spectrophotometer and Inductively Coupled Plasma—Optical Emission Spectroscopy (ICP-OES). Hierarchical clustering analysis was performed to study a correlation between the chemical composition of urban pollution and meteorological parameters. The suburban area displays an increase in PM10 concentrations and natural elemental markers during the dry (increased wind intensity, resuspension of soil dust) season. Meanwhile, densely urbanized area shows increased total PM10 concentrations and anthropogenic elemental markers during the wet season, which may point to the worsened combustion and traffic conditions. This might indicate the prevalence of cardiovascular and respiratory problems in motorized areas of the cities in the developing world.

Stopover Site Fidelity by Tennessee Warblers at a Southern Appalachian High-elevation Site

2012 ◽  
Vol 124 (2) ◽  
pp. 366-370 ◽  
Author(s):  
David F. Vogt ◽  
Mark E. Hopey ◽  
G. Rad Mayfield ◽  
Eric C. Soehren ◽  
Laura M. Lewis ◽  
...  
Keyword(s):  
Site Fidelity ◽  
High Elevation ◽  
Stopover Site ◽  
Southern Appalachian ◽  
High Elevation Site

scholarly journals Two years of online measurement of fine particulate nitrate in the western Yangtze River Delta: influences of thermodynamics and N<sub>2</sub>O<sub>5</sub> hydrolysis

2018 ◽  
Vol 18 (23) ◽  
pp. 17177-17190 ◽  
Author(s):  
Peng Sun ◽  
Wei Nie ◽  
Xuguang Chi ◽  
Yuning Xie ◽  
Xin Huang ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Yangtze River ◽  
Nitrate Concentration ◽  
Yangtze River Delta ◽  
River Delta ◽  
Water Soluble ◽  
Online Measurement ◽  
High Concentration ◽  
Soluble Ions ◽  
Water Soluble Ions

Abstract. Particulate nitrate contributes a large fraction of secondary aerosols. Despite understanding of its important role in regional air quality and global climate, long-term continuous measurements are rather limited in China. In this study, we conducted online measurement of PM2.5 (particulate matter with diameters less than 2.5 µm) nitrate for 2 years from March 2014 to February 2016 using the Monitor for AeRosols and Gases in ambient Air (MARGA) in the western Yangtze River Delta (YRD), eastern China, and investigate the main factors that influenced its temporal variations and formation pathways. Compared to other sites in China, an overall high concentration of particulate nitrate was observed, with a mean value of 15.8 µg m−3 (0.5 to 92.6 µg m−3). Nitrate on average accounted for 32 % of the total mass of water-soluble ions and the proportion increased with PM loading, indicating that nitrate is a major driver of haze pollution episodes in this region. Sufficient ammonia drove most nitrate into the particle phase in the form of ammonium nitrate. A typical seasonal cycle of nitrate was observed, with the concentrations in winter on average 2 times higher than those in summer mainly due to different meteorological conditions. In summer, the diurnal variation of particulate nitrate was determined by thermodynamic equilibrium, resulting in a much lower concentration during daytime despite a considerable photochemical production. Air masses from the polluted YRD and biomass burning region contributed to the high nitrate concentration during summer. In winter, particulate nitrate did not reveal an evident diurnal variation. Regional transport from northern China played an important role in enhancing nitrate concentration. A total of 18 nitrate episodes were selected to understand the processes that drive the formation of high concentration of nitrate. Rapid nitrate formation was observed during the pre-episode (the day before nitrate episode day) nights, and dominated the increase of total water-soluble ions. Calculated nitrate from N2O5 hydrolysis was highly correlated to and accounted for 80 % of the observed nitrate, suggesting that N2O5 hydrolysis was a major contributor to the nitrate episodes. Our results suggested that rapid formation of nitrate could be a main cause for extreme aerosol pollution events in the YRD during winter, and illustrated the urgent need to control NOx emission.

Environmental correlates of herpetofaunal diversity in Costa Rica

2010 ◽  
Vol 26 (5) ◽  
pp. 521-531 ◽  
Author(s):  
David Laurencio ◽  
Lee A. Fitzgerald
Keyword(s):  
Costa Rica ◽  
Species Diversity ◽  
Beta Diversity ◽  
Geographic Distance ◽  
Alpha Diversity ◽  
High Elevation ◽  
Diversity Patterns ◽  
Regional Diversity ◽  
Environmental Correlates ◽  
High Elevation Site

Abstract:Disentangling local and historical factors that determine species diversity patterns at multiple spatial scales is fundamental to elucidating processes that govern ecological communities. Here we investigated how environmental correlates may influence diversity at local and regional scales. Primarily utilizing published species lists, amphibian and reptile alpha and beta diversity were assessed at 17 well-surveyed sites distributed among ecoregions throughout Costa Rica. The degree to which regional species diversity patterns were related to environmental variables and geographic distance was determined using Canonical Correspondence Analysis and Mantel tests. Amphibian alpha diversity was highest in lowland Pacific sites (mean = 43.3 species) and lowest at the high elevation site (9 species). Reptile alpha diversity values were high for both lowland Atlantic (mean = 69.5 species) and lowland Pacific (mean = 67 species) sites and lowest for the high elevation site (8 species). We found high species turnover between local sites and ecoregions, demonstrating the importance of beta diversity in the determination of regional diversity. For both amphibians and reptiles, beta diversity was highest between the high-elevation site and all others, and lowest among lowland sites within the same ecoregion. The effect of geographic distance on beta diversity was minor. Ecologically significant climatic variables related to rain, temperature, sunshine and insolation were found to be important determinants of local and regional diversity for both amphibians and reptiles in Costa Rica.

The first meteorological observations at a tropical high elevation site: Antisana, 1846

2016 ◽  
Vol 13 (6) ◽  
pp. 1047-1055 ◽  
Author(s):  
Ana Mª M. Farrona ◽  
Fernando Domínguez-Castro ◽  
Mª Cruz Gallego ◽  
José M. Vaquero
Keyword(s):  
High Elevation ◽  
High Elevation Site ◽  
Meteorological Observations

YIELD AND QUALITY OF RED STIGMAS FROM DIFFERENT SAFFRON STRAINS AT CONTRASTING MEDITERRANEAN SITES

2006 ◽  
Vol 42 (4) ◽  
pp. 399-409 ◽  
Author(s):  
S. K. YAU ◽  
M. NIMAH ◽  
I. TOUFEILI
Keyword(s):  
Field Experiments ◽  
High Elevation ◽  
Crocus Sativus ◽  
Coastal Site ◽  
Yield And Quality ◽  
High Elevation Site ◽  
Colour Strength ◽  
Semi Arid

Three different saffron strains (Crocus sativus, C. sativus var. ‘cashmerianus’ and C. cartwrightianus) were tested for two years in field experiments to study their red stigma yield and quality. The experiments were performed at a high-elevation (rainfed or irrigated) site and a coastal site in Lebanon. On average, the two C. sativus strains gave more flowers and stigma yield than C. cartwrightianus. The former was more productive in the more favourable environments, especially at the warmer coastal site, than the latter. C. sativus ‘cashmerianus’, which yielded better at the coastal site in 2004 and gave a stronger colour strength and aroma, appeared to be the better choice for the area. Mean yield at the coastal site was twice that at the non-irrigated high-elevation site. On average, saffron produced at the coastal site had more colouring strength and bitterness than that produced at the high-elevation site. Nevertheless, viable commercial saffron production may still be possible in the semi-arid, high-elevation Bekaa Valley if irrigation can be provided.

scholarly journals Evaluation and application of a semi-continuous chemical characterization system for water soluble inorganic PM<sub>2.5</sub> and associated precursor gases

2009 ◽  
Vol 2 (1) ◽  
pp. 65-80 ◽  
Author(s):  
K. J. Godri ◽  
G. J. Evans ◽  
J. Slowik ◽  
A. Knox ◽  
J. Abbatt ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Chemical Characterization ◽  
Water Soluble ◽  
High Temporal Resolution ◽  
Field Sampling ◽  
Inorganic Particles ◽  
Regional Sources ◽  
Inorganic Species ◽  
Seasonal And Diurnal Variations ◽  
Continuous Chemical

Abstract. Water soluble inorganic particles components (Cl−, SO42−, NO3−, and NH4+) and concentrations of their associated precursor gases (HCl, SO2, HNO3, NH3) were semi-continuously measured using the Dionex Gas Particle Ion Chromatography (GPIC) system. Sampling was conducted adjacent to a high traffic street in downtown Toronto, Canada from June 2006 to March 2007. This study evaluated the precision and accuracy of field sampling measurements with the GPIC both relative to filter based measurements and other co-located semi-continuous instruments (R&amp;P 8400N Nitrate Monitor, API Fluorescent SO2 Gas Analyzer, and Aerodyne C-ToF-AMS). High temporal resolution PM2.5 mass reconstruction is presented by combining GPIC measured inorganic species concentrations and Sunset Laboratory OCEC Analyzer determined organics concentrations. Field sampling results were also examined for seasonal and diurnal variations. HNO3 and particulate nitrate exhibited diurnal variation and strong partitioning to the gas phase was observed during the summer. Ammonia and particulate ammonium also demonstrated seasonal differences in their diurnal profiles. However, particulate sulphate and SO2 showed no diurnal variation regardless of season suggesting dominant transport from regional sources throughout the year.

scholarly journals Sources of organic carbon in fine particulate matter in northern European urban air

2008 ◽  
Vol 8 (20) ◽  
pp. 6281-6295 ◽  
Author(s):  
S. Saarikoski ◽  
H. Timonen ◽  
K. Saarnio ◽  
M. Aurela ◽  
L. Järvi ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Diurnal Variation ◽  
Long Range ◽  
Major Ions ◽  
Water Soluble ◽  
Anthropogenic Sources ◽  
Biomass Combustion ◽  
Long Range Transport ◽  
Northern European ◽  
Range Transport

Abstract. A major fraction of fine particle matter consists of organic carbon (OC) but its origin is still inadequately known. In this study the sources of OC were investigated in the northern European urban environment in Helsinki, Finland. Measurements were carried out over one year and they included both filter (PM1) and online methods. From the filter samples OC, elemental carbon (EC), water-soluble OC (WSOC), levoglucosan and major ions were analyzed. Filter data together with the concentrations of inorganic gases were analyzed by Positive matrix factorization (PMF) in order to find the sources of OC (and WSOC) on an annual as well as on a seasonal basis. In order to study the diurnal variation of sources, OC and EC were measured by a semicontinuous OC/EC analyzer and major ions were determined by a Particle-into-Liquid Sampler coupled to ion chromatographs. According to PMF, OC concentrations were impacted by four sources: biomass combustion, traffic, long-range transport and secondary production. On an annual basis the OC concentration was dominated by secondary organic aerosol (SOA). Its contribution to OC was as high as 64% in summer, which besides anthropogenic sources may also result from the large biogenic volatile organic carbon (VOC) emissions in the boreal region. In winter biomass combustion constituted the largest fraction in OC due to domestic wood combustion for heating purposes. Traffic contributed to OC from 15 to 27%. Regarding the diurnal variation, the contribution from traffic was higher from 08:00 to 18:00 on weekdays than on weekends. The contribution from long-range transport to OC was 24% on average. All four sources also influenced the WSOC concentrations, however, the contribution of SOA was significantly larger for WSOC than OC.

scholarly journals Characterization of Airborne Microbial Communities at a High-Elevation Site and Their Potential To Act as Atmospheric Ice Nuclei

2009 ◽  
Vol 75 (15) ◽  
pp. 5121-5130 ◽  
Author(s):  
Robert M. Bowers ◽  
Christian L. Lauber ◽  
Christine Wiedinmyer ◽  
Micah Hamady ◽  
Anna G. Hallar ◽  
...  
Keyword(s):  
Microbial Communities ◽  
High Elevation ◽  
Small Subunit ◽  
Microbial Community Analysis ◽  
Rrna Gene ◽  
Atmospheric Conditions ◽  
Small Subunit Rrna ◽  
Ice Nuclei ◽  
High Elevation Site ◽  
Bacteria And Fungi

ABSTRACT Bacteria and fungi are ubiquitous in the atmosphere. The diversity and abundance of airborne microbes may be strongly influenced by atmospheric conditions or even influence atmospheric conditions themselves by acting as ice nucleators. However, few comprehensive studies have described the diversity and dynamics of airborne bacteria and fungi based on culture-independent techniques. We document atmospheric microbial abundance, community composition, and ice nucleation at a high-elevation site in northwestern Colorado. We used a standard small-subunit rRNA gene Sanger sequencing approach for total microbial community analysis and a bacteria-specific 16S rRNA bar-coded pyrosequencing approach (4,864 sequences total). During the 2-week collection period, total microbial abundances were relatively constant, ranging from 9.6 × 105 to 6.6 × 106 cells m−3 of air, and the diversity and composition of the airborne microbial communities were also relatively static. Bacteria and fungi were nearly equivalent, and members of the proteobacterial groups Burkholderiales and Moraxellaceae (particularly the genus Psychrobacter) were dominant. These taxa were not always the most abundant in freshly fallen snow samples collected at this site. Although there was minimal variability in microbial abundances and composition within the atmosphere, the number of biological ice nuclei increased significantly during periods of high relative humidity. However, these changes in ice nuclei numbers were not associated with changes in the relative abundances of the most commonly studied ice-nucleating bacteria.

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