MICROBIOLOGICAL STUDIES OF AIR MASSES OVER MONTREAL DURING 1950 AND 1951

1954 ◽  
Vol 32 (5) ◽  
pp. 591-600 ◽  
Author(s):  
C. D. Kelly ◽  
S. M. Pady
Keyword(s):  
Agricultural Land ◽  
Ground Level ◽  
The Sun ◽  
Cultivated Land ◽  
High Fungus ◽  
Air Masses ◽  
Above Ground Level ◽  
Air Sampler ◽  
The Pacific ◽  
Bacteria And Fungi

The numbers of bacteria and fungi in air masses over Montreal, Canada, were determined by sampling at the top of the Sun Life Building, 400 ft. above ground level, from September 1950 to December 1951. During 113 days of sampling, 978 exposures were made with agar plates in the General Electric Bacterial Air Sampler and the Bourdillon Slit Sampler. Eighty-seven exposures for fungus spores were made with silicone coated slides in the Slit Sampler. Most of the air encountered was continental polar either moving direct to Montreal, found on 38 days, or modified by moving over agricultural land, sampled on 51 days. Maritime polar air from the Atlantic was encountered on 21 days, and from the Pacific on one day. Maritime tropic air from the Gulf of Mexico was encountered twice. The seasonal variation of bacteria and fungi in all air masses showed low counts in January, February, and March. Higher bacterial counts were obtained from early April into July and from early September into November, covering a range from 3.0 to 55.0 per cu. ft. Lower counts were found during late July and August. The high fungus counts extended from May into November and covered a range from 5.0 to 56.3 per cu. ft. Both continental polar and maritime polar air that moved over considerable cultivated land showed generally higher counts than where these air masses moved directly to Montreal.

FUNGI IN AIR MASSES OVER MONTREAL DURING 1950 AND 1951

1956 ◽  
Vol 34 (1) ◽  
pp. 1-15 ◽  
Author(s):  
S. M. Pady ◽  
L. Kapica
Keyword(s):  
Seasonal Variation ◽  
Pollen Grains ◽  
Average Concentration ◽  
Yeast Cells ◽  
The Sun ◽  
Air Masses ◽  
Air Sampler ◽  
Agricultural Areas ◽  
Very High ◽  
Made In

Numbers and kinds of fungi were determined from nutrient plate and silicone slide studies from the roof of the Sun Life Building, Montreal, between September 1950 and December 1951. Exposures of plates were made in the General Electric Bacterial Air Sampler, and plates and silicone slides in the Bourdillon Slit Sampler. A total of 978 exposures was made on 113 sampling days during 16 months; 507 plates in the G. E. Sampler, 344 plates and 127 slides in the Slit Sampler. Of 40,359 colonies examined, Cladosporium, Penicillium, yeasts, Aspergillus, Alternaria, and Actinomycetes were commonest, constituting 47.7, 15.8, 10.4, 4.6, 4.2, and 2.2% of the total. The next commonest fungi were Pullularia, Oöspora, Fusarium, Stemphylium, Verticillium, Rhizopus, Spicaria, Scopulariopsis, Phoma, Mucor, Botrytis, Cephalosporium, Trichoderma, Helmin-thosporium, Neurospora, Papularia, Cephalothecium, Pyrenochaeta, Zythia, and Nigrospora. In addition 12 genera were infrequently found. Unidentified colonies numbered 174 and nonsporulating 3371 (8.3%). On a cubic foot basis numbers in the plates varied from 17.7 per cu. ft. in August to 0.4 per cu. ft in February.Fungus spores showed a seasonal variation with summer highs averaging 244 per cu. ft. in July to a low of 0.8 per cu. ft. in December. The most abundant spores were Cladosporium, yeasts, smuts, Fusarium, Alternaria, Venturia-like, Stemphylium, rusts, Septoria, and Helminthosporium. Hyphal fragments and pollen grains were present also. On eight occasions during the summer, readings of over 200 spores per cu. ft. were recorded, the maximum being 445 per cu. ft. on September 6, 1951. Cladosporium in August reached a peak of 74.1 per cu. ft. and yeast cells in July had an average concentration of 100 per cu. ft.An analysis of the air masses indicated that pure polar air carried low numbers of fungi, whereas tropical air had very high numbers. Most of the air masses were modified polar air and their fungus content varied considerably. The fungi in the air over Montreal are believed to have had their origin in agricultural areas.

STUDIES ON MICROORGANISMS IN ARCTIC AIR DURING 1949 AND 1950

1953 ◽  
Vol 31 (1) ◽  
pp. 107-122 ◽  
Author(s):  
S. M. Pady ◽  
C. D. Kelly
Keyword(s):  
Ground Level ◽  
The Arctic ◽  
The South ◽  
Air Sampler ◽  
Large Numbers ◽  
Daily Sampling ◽  
Baker Lake ◽  
Resolute Bay ◽  
Bacteria And Fungi

The numbers of bacteria and fungi in arctic air were determined by daily sampling at Churchill, Man., during July and August 1950, and in three flights, one to Baker Lake, N.W.T., and the remainder to Resolute Bay, N.W.T. Of the three samplers which were used simultaneously the G.E. Bacterial Air Sampler gave slightly higher readings than the Bourdillon Slit Sampler, while the filter gave low readings throughout.Daily averages of bacteria at ground level ranged from 0.9 to 30.1 per cu. ft., and in the flight to Resolute Bay from 0.3 to 0.9 per cu. ft. while the comparable readings of the fungi were 0.5 to 4.4 and 0.01 to 0.7 per cu. ft. with the slit sampler. Considerable variation occurred in ground level samples, not only from day to day but throughout the day. Silicone slide studies revealed high numbers, up to 115 per cu. ft., which includes a high proportion of nonviable fungus spores. Most of the organisms are soil inhabiting forms but some fungus parasites were present, chiefly as smut (Ustilago) spores. Evidence indicates that winds originating in the south carry large numbers of organisms northward, many of which are nonviable when they reach the arctic, while north winds of polar origin contain very low numbers even in the summer.

scholarly journals Spatial Analysis (Measurements at Heights of 10 m and 20 m above Ground Level) of the Concentrations of Particulate Matter (PM10, PM2.5, and PM1.0) and Gaseous Pollutants (H2S) on the University Campus: A Case Study

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Robert Cichowicz ◽  
Maciej Dobrzański
Keyword(s):  
Spatial Distribution ◽  
Hydrogen Sulfide ◽  
Particulate Matter ◽  
Air Quality ◽  
Spatial Analysis ◽  
Ground Level ◽  
Leeward Side ◽  
High Concentration ◽  
Above Ground Level ◽  
High Concentrations

Spatial analysis of the distribution of particulate matter PM10, PM2.5, PM1.0, and hydrogen sulfide (H2S) gas pollution was performed in the area around a university library building. The reasons for the subject matter were reports related to the perceptible odor characteristic of hydrogen sulfide and a general poor assessment of air quality by employees and students. Due to the area of analysis, it was decided to perform measurements at two heights, 10 m and 20 m above ground level, using measuring equipment attached to a DJI Matrice 600 unmanned aerial vehicle (UAV). The aim of the measurements was air quality assessment and investigate the convergence of the theory of air flow around the building with the spatial distribution of air pollutants. Considerable differences of up to 63% were observed in the concentrations of pollutants measured around the building, especially between opposite sides, depending on the direction of the wind. To explain these differences, the theory of aerodynamics was applied to visualize the probable airflow in the direction of the wind. A strong convergence was observed between the aerodynamic model and the spatial distribution of pollutants. This was evidenced by the high concentrations of dust in the areas of strong turbulence at the edges of the building and on the leeward side. The accumulation of pollutants was also clearly noticeable in these locations. A high concentration of H2S was recorded around the library building on the side of the car park. On the other hand, the air turbulence around the building dispersed the gas pollution, causing the concentration of H2S to drop on the leeward side. It was confirmed that in some analyzed areas the permissible concentration of H2S was exceeded.

scholarly journals Spatial Differentiation of Cultivated Land Use Intensification in Village Settings: A Survey of Typical Chinese Villages

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 249
Author(s):  
Quanfeng Li ◽  
Zhe Dong ◽  
Guoming Du ◽  
Aizheng Yang
Keyword(s):  
Land Use ◽  
Food Security ◽  
Socioeconomic Development ◽  
Agricultural Land ◽  
Spatial Differentiation ◽  
Cultivated Land ◽  
Output State ◽  
Land Use Intensification ◽  
Development Levels ◽  
Business Entities

The intensified use of cultivated land is essential for optimizing crop planting practices and protecting food security. This study employed a telecoupling framework to evaluate the cultivated land use intensification rates in typical Chinese villages (village cultivated land use intensifications—VCLUIs). The pressure–state–response (PSR) model organizes the VCLUI indexes including the intensity press, output state, and structural response of cultivated land use. Empirical analysis conducted in Baiquan County, China, indicating that the cultivated land use intensification levels of the whole county were low. However, the intensifications of villages influenced by physical and geographic locations and socioeconomic development levels varied significantly. This paper also found that variations in the VCLUIs were mainly dependent on new labor-driven social subsystem differences. Thus, the expanding per capita farmland scales and increasing numbers of new agricultural business entities were critical in improving the VCLUI. Overall, the theoretical framework proposed in this study was demonstrated to be effective in analyzing interactions among the natural, social, and economic subsystems of the VCLUI. The findings obtained in this study potentially have important implications for future regional food security, natural stability, and agricultural land use sustainability.

scholarly journals A Climatology of Nocturnal Low-Level Jets at Cabauw

2009 ◽  
Vol 48 (8) ◽  
pp. 1627-1642 ◽  
Author(s):  
P. Baas ◽  
F. C. Bosveld ◽  
H. Klein Baltink ◽  
A. A. M. Holtslag
Keyword(s):  
Wind Speed ◽  
Ground Level ◽  
Geostrophic Wind ◽  
Stable Stratification ◽  
Radiative Cooling ◽  
Inertial Oscillation ◽  
Stable Boundary Layers ◽  
Above Ground Level ◽  
Low Level ◽  
Low Level Jets

Abstract A climatology of nocturnal low-level jets (LLJs) is presented for the topographically flat measurement site at Cabauw, the Netherlands. LLJ characteristics are derived from a 7-yr half-hourly database of wind speed profiles, obtained from the 200-m mast and a wind profiler. Many LLJs at Cabauw originate from an inertial oscillation, which develops after sunset in a layer decoupled from the surface by stable stratification. The data are classified to different types of stable boundary layers by using the geostrophic wind speed and the isothermal net radiative cooling as classification parameters. For each of these classes, LLJ characteristics like frequency of occurrence, height above ground level, and the turning of the wind vector across the boundary layer are determined. It is found that LLJs occur in about 20% of the nights, are typically situated at 140–260 m above ground level, and have a speed of 6–10 m s−1. Development of a substantial LLJ is most likely to occur for moderate geostrophic forcing and a high radiative cooling. A comparison with the 40-yr ECMWF Re-Analysis (ERA-40) is added to illustrate how the results can be used to evaluate the performance of atmospheric models.

Agrodeforestation and the loss of agrobiodiversity in the Pacific Islands: a call for conservation

2014 ◽  
Vol 20 (2) ◽  
pp. 180 ◽  
Author(s):  
Randolph Thaman
Keyword(s):  
Biodiversity Conservation ◽  
Sustainable Management ◽  
Pacific Islands ◽  
Agricultural Land ◽  
Ecosystem Goods And Services ◽  
Livelihood Security ◽  
Goods And Services ◽  
The Pacific ◽  
Aichi Biodiversity Targets

Our ability to conserve biodiversity and to adapt to climate, environmental and economic change in the Pacific Islands will be greatly dependent on the conservation, restoration and enrichment of biodiversity within traditional multispecies agricultural land use systems. “Agrobiodiversity” is the most well-known, culturally-useful and accessible biodiversity on most islands and constitutes the most important foundation for ecosystem goods and services that support food, health, energy and livelihood security. This rich Pacific agrobiodiversity heritage, including associated ethnobiodiversity is highly threatened and deserves more prominence in mainstream conservation initiatives as a foundation for long-term sustainability. Such action is in line with Aichi Biodiversity Targets 7 and 13 which set goals for sustainable management of agriculture, fisheries and forestry, and the maintenance of genetic diversity as critical for successful biodiversity conservation globally. It is also supported by the findings of the Japan Satoyama-Satoumi Assessment, which stresses the critical importance of biodiversity conservation and ecosystem services provided by traditional agricultural and village landscapes.

scholarly journals Stratosphere-troposphere exchange in the vicinity of a tropopause fold

2016 ◽  
Author(s):  
Christiane Hofmann ◽  
Astrid Kerkweg ◽  
Peter Hoor ◽  
Patrick Jöckel
Keyword(s):  
Atmospheric Chemistry ◽  
Climate Model ◽  
Ground Level ◽  
Global Model ◽  
Similar Process ◽  
Limited Area ◽  
Lagrangian Analysis ◽  
Air Masses ◽  
Model Instance ◽  
Lagrangian Study

Abstract. Transport of air masses from the stratosphere to the troposphere along tropopause folds can lead to peaked ozone concentrations at ground level and hereby influence the long-term trend of tropospheric ozone. To improve the understanding of responsible processes and preferred regions of exchange, transient and reversible exchange processes in the vicinity of a tropopause fold are analysed on the basis of a case study. The global and regional atmospheric chemistry model system MECO(n), which couples the limited-area atmospheric chemistry and climate model COSMO-CLM/MESSy to the global model ECHAM5/MESSy for Atmospheric Chemistry (EMAC) is applied. Using similar process parametrisations in both model instances, the system allows for very consistent, simultaneous simulations at different spatial resolutions. Simulated ozone enhancements at ground level, caused by descending stratospheric air masses, are evaluated with observational data. Because of the coarse resolution of the global model, the observed ozone enhancements are not captured by the global model instance. However, the results of the finer resolved, regional model instance coincide well with the measurements. Based on the combination of Eulerian and Lagrangian analysis methods it is shown that stratosphere-troposphere-exchange (STE) in the vicintity of the tropopause fold occurs in regions of turbulence and diabatic processes. Within the framework of a Lagrangian study the efficiency of mixing along a tropopause fold is quantified, showing that almost all (97 %) of the air masses originating in the tropopause fold are transported into the troposphere during the following two days.

scholarly journals The Bakerian lecture —Regularities and irregularities in the ionosphere—I

1937 ◽  
Vol 162 (911) ◽  
pp. 451-479 ◽  
Keyword(s):  
Specific Conductivity ◽  
Wave Length ◽  
Ground Level ◽  
Short Wave ◽  
The State ◽  
Total Conductivity ◽  
The Sun ◽  
Magnetic Studies ◽  
Short Wave Length ◽  
Radio Measurements

Our knowledge concerning the state of the atmosphere lying above about 80 km. in height has been derived from experiments on radio wave reflexion as well as from studies of terrestrial magnetism and of the aurora. The information derived from radio experiments is, fortunately, in the nature of a supplement to, rather than a duplicate of, information derivable in other ways. As one of the best examples in this connexion may be mentioned the question of electrical conductivity. Here the magnetic studies of Schuster and Chapman yield an estimate of the total conductivity for currents travelling horizontally, whereas the radio measurements give the state of ionization at different levels from which the specific conductivity at those levels may be estimated. One of the most striking things about the ionosphere is the marked solar control. Speaking generally it may be said that the ionization increases and decreases as the sun rises and sets. Again, speaking generally, we may say that the main part of the ionization is caused by solar-violet light. The rays from the sun meet the outer layers of the atmosphere first and the short wave-length radiation is absorbed there, causing ionization. It thus comes about that the study of the ionosphere becomes the study of an interesting part of the sun's spectrum which cannot be detected at ground level. It also becomes the study of certain atomic processes such as photo-ionization, recombination of ions and attachment of electrons to neutral molecules such as cannot be investigated at very low pressure in the laboratory, because of the influence of the walls of the vessel confining the gas.

scholarly journals Synergetic monitoring of Saharan dust plumes and potential impact on surface: a case study of dust transport from Canary Islands to Iberian Peninsula

2011 ◽  
Vol 11 (7) ◽  
pp. 3067-3091 ◽  
Author(s):  
C. Córdoba-Jabonero ◽  
M. Sorribas ◽  
J. L. Guerrero-Rascado ◽  
J. A. Adame ◽  
Y. Hernández ◽  
...  
Keyword(s):  
Iberian Peninsula ◽  
Particle Deposition ◽  
Ground Level ◽  
In Situ Measurements ◽  
Saharan Dust ◽  
Dust Transport ◽  
Air Masses ◽  
Potential Impact

Abstract. The synergetic use of meteorological information, remote sensing both ground-based active (lidar) and passive (sun-photometry) techniques together with backtrajectory analysis and in-situ measurements is devoted to the characterization of dust intrusions. A case study of air masses advected from the Saharan region to the Canary Islands and the Iberian Peninsula, located relatively close and far away from the dust sources, respectively, was considered for this purpose. The observations were performed over three Spanish geographically strategic stations within the dust-influenced area along a common dust plume pathway monitored from 11 to 19 of March 2008. A 4-day long dust event (13–16 March) over the Santa Cruz de Tenerife Observatory (SCO), and a linked short 1-day dust episode (14 March) in the Southern Iberian Peninsula over the Atmospheric Sounding Station "El Arenosillo" (ARN) and the Granada station (GRA) were detected. Meteorological conditions favoured the dust plume transport over the area under study. Backtrajectory analysis clearly revealed the Saharan region as the source of the dust intrusion. Under the Saharan air masses influence, AERONET Aerosol Optical Depth at 500 nm (AOD500) ranged from 0.3 to 0.6 and Ångström Exponent at 440/675 nm wavelength pair (AE440/675) was lower than 0.5, indicating a high loading and predominance of coarse particles during those dusty events. Lidar observations characterized their vertical layering structure, identifying different aerosol contributions depending on altitude. In particular, the 3-km height dust layer transported from the Saharan region and observed over SCO site was later on detected at ARN and GRA stations. No significant differences were found in the lidar (extinction-to-backscatter) ratio (LR) estimation for that dust plume over all stations when a suitable aerosol scenario for lidar data retrieval is selected. Lidar-retrieved LR values of 60–70 sr were obtained during the main dust episodes. These similar LR values found in all the stations suggest that dust properties were kept nearly unchanged in the course of its medium-range transport. In addition, the potential impact on surface of that Saharan dust intrusion over the Iberian Peninsula was evaluated by means of ground-level in-situ measurements for particle deposition assessment together with backtrajectory analysis. However, no connection between those dust plumes and the particle sedimentation registered at ground level is found. Differences on particle deposition processes observed in both Southern Iberian Peninsula sites are due to the particular dust transport pattern occurred over each station. Discrepancies between columnar-integrated and ground-level in-situ measurements show a clear dependence on height of the dust particle size distribution. Then, further vertical size-resolved observations are needed for evaluation of the impact on surface of the Saharan dust arrival to the Iberian Peninsula.

scholarly journals Influence of the ambient humidity on the concentration of natural deposition-mode ice-nucleating particles

2016 ◽  
Vol 16 (2) ◽  
pp. 927-932 ◽  
Author(s):  
M. L. López ◽  
E. E. Ávila
Keyword(s):  
Relative Humidity ◽  
Linear Trend ◽  
Ground Level ◽  
Ambient Air ◽  
Air Masses ◽  
Ambient Relative Humidity ◽  
Thermodynamic Conditions ◽  
Rainy Days ◽  
Deposition Mode

Abstract. This study reports measurements of deposition-mode ice-nucleating particle (INP) concentrations at ground level during the period July–December 2014 in Córdoba, Argentina. Ambient air was sampled into a cloud chamber where the INP concentration was measured at a temperature of −25 °C and a 15 % supersaturation over ice. Measurements were performed on days with different thermodynamic conditions, including rainy days. The effect of the relative humidity at ground level (RHamb) on the INP concentration was analyzed. The number of INPs activated varied from 1 L−1 at RHamb of 25 % to 30 L−1 at RHamb of 90 %. In general, a linear trend between the INP concentration and the RHamb was found, suggesting that this variability must be related to the effectiveness of the aerosols acting as INPs. From the backward trajectories analysis, it was found that the link between INP concentration and RHamb is independent of the origin of the air masses. The role of biological INPs and nucleation occurring in pores and cavities was discussed as a possible mechanism to explain the increase of the INP concentration during high ambient relative humidity events. This work provides valuable measurements of deposition-mode INP concentrations from the Southern Hemisphere where INP data are sparse so far.

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