Study of coarse aerosol using an adapted FAN nephelometer

2021 ◽  
Author(s):  
A. A. Isakov ◽  
Anatoly T ◽  
D. P. Gubanova
Keyword(s):  
Coarse Aerosol

Aircraft Applications of Insecticides in East Africa. VI.—Applications of a coarse Aerosol containning DDT to control the Tsetse Flies, Glossina morsitans Westw., Glossina swynnertoni Aust. and Glossina pallidipes Aust.

1954 ◽  
Vol 45 (3) ◽  
pp. 585-603 ◽  
Author(s):  
K. S. Hocking ◽  
D. Yeo ◽  
D. G. Anstey
Keyword(s):  
Random Effects ◽  
Glossina Pallidipes ◽  
Tsetse Flies ◽  
Glossina Morsitans ◽  
Median Diameter ◽  
Coarse Aerosol ◽  
Savannah Woodland ◽  
Mass Median ◽  
Glossina Swynnertoni ◽  
Mass Median Diameter

An experiment is described where applications of a coarse aerosol were made to savannah woodland containing the tsetse flies, Glossina moritans Westw., G. swynnertoni Aust. and G. pallidipes Aust.Seven applications were made, each at a nominal dosage of 0·25 lb. of technical DDT per acre and 0·25 gallons of solution per acre. The applications in any particular part of the treaed woodland covered an interval of 90 days, or rather more than two pupal periods.The coarse aerosol was produced by emitting the insecticidal solution under pressure through fine nozzles fitted to a boom. It had a mass median diameter of approximately 60 microns, and droplet dismeters varied from a few microns to approximately 200 microns.The population of G. pallidipes was so drastically reduced that it has subsequently dies out. The reduction of G. morsitans was approximately 95 per cent. The differences between the reductions are attributed mainly to differences between the ease with which the three species can be killed. It is pointed out that this is not necessarily equivalent to differences in susceptibility.Comparisons are made with previous experiments, and the different results of the various experiments are difficult to explian satisfactory. The increased cover in savannah areas during the leafy period may have reduced the effectiveness of the applications, and the total periods covered by the various series of applications were probably also important. Random effects, leading to ineffective treatments, may also be important.Costs are discussed.

scholarly journals Distribution of Atmospheric Aerosol over the South China Sea

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Shih-Jen Huang ◽  
Chen-Chih Lin
Keyword(s):  
South China Sea ◽  
South China ◽  
Aerosol Particles ◽  
Correlation Coefficients ◽  
The South China Sea ◽  
The South ◽  
China Sea ◽  
Fine Aerosol ◽  
Coarse Aerosol

The satellite-derived aerosol optical depth (AOD) data is used to investigate the distribution of aerosol over the South China Sea (SCS). High correlation coefficients are found between in situ AERONET data and satellite AOD measurements around the SCS with the highest coefficient of 0.9 on the Dongsha Island (i.e., Pratas Island). The empirical orthogonal function (EOF) analysis of AOD over the SCS shows that high AOD is always found around offshore areas of China, Indochina, Sumatra, and Borneo. Besides, spring is the major season of occurring coarse aerosol particles (AOT_C) but fine aerosol particles (AOT_F) occur yearly. The biomass burning is found in Indochina during March and April, and so it is in Sumatra and Borneo from August to October. The results also show that the AOT_F are higher during El Niño events, but higher AOT_C are found in La Niña years.

VERTICAL CONCENTRATION PROFILES OF FINE AND COARSE AEROSOL PARTICLES OVER A SUBURBAN SAMPLING SITE NEAR BUDAPEST, HUNGARY

1992 ◽  
Vol 02 (02) ◽  
pp. 179-187 ◽  
Author(s):  
S. AMEMIYA ◽  
T. KATOH ◽  
I. BORBÉLY-KISS ◽  
E. KOLTAY ◽  
GY. SZABÓ ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Atmospheric Aerosol ◽  
Aerosol Particles ◽  
Sampling Site ◽  
Enrichment Factors ◽  
Concentration Profiles ◽  
Height Distribution ◽  
Deposition Velocities ◽  
Coarse Aerosol ◽  
Pixe Method

Samples of atmospheric aerosol particles collected at various height over a suburban sampling site were analyzed with respect to 13 elements by PIXE method. Concentrations, enrichment factors, and fine-to-coarse concentration ratios of the fractions were obtained by averaging over height distribution. In one of the sampling experiments dry-deposition velocities were deduced for seven elements from the height distribution.

scholarly journals Increased absorption by coarse aerosol particles over the Gangetic–Himalayan region

2014 ◽  
Vol 14 (3) ◽  
pp. 1159-1165 ◽  
Author(s):  
V. S. Manoharan ◽  
R. Kotamarthi ◽  
Y. Feng ◽  
M. P. Cadeddu
Keyword(s):  
Atmospheric Aerosols ◽  
Radiative Forcing ◽  
Climate Models ◽  
Monsoon Season ◽  
Regional Scale ◽  
Chemical Properties ◽  
Aerosol Forcing ◽  
Post Monsoon Season ◽  
Absorbing Aerosols ◽  
Coarse Aerosol

Abstract. Each atmospheric aerosol type has distinctive light-absorption characteristics related to its physical/chemical properties. Climate models treat black carbon as the main light-absorbing component of carbonaceous atmospheric aerosols, while absorption by some organic aerosols is also considered, particularly at ultraviolet wavelengths. Most absorbing aerosols are assumed to be < 1 μm in diameter (sub-micron). Here we present results from a recent field study in India, primarily during the post-monsoon season (October–November), suggesting the presence of absorbing aerosols sized 1–10 μm. Absorption due to super-micron-sized particles was nearly 30% greater than that due to smaller particles. Periods of increased absorption by larger particles ranged from a week to a month. Radiative forcing calculations under clear-sky conditions show that super-micron particles account for nearly 44% of the total aerosol forcing. The origin of the large aerosols is unknown, but meteorological conditions indicate that they are of local origin. Such economic and habitation conditions exist throughout much of the developing world. Hence, large absorbing particles could be an important component of the regional-scale atmospheric energy balance.

Aircraft Applications of Insecticides in East Africa. XI.—Applications of a coarse Aerosol to control Glossina morsitans Westw. At Urambo, Tanganyika, and G. morsitans Westw. and G. pallidipes Aust. In Lango County, Uganda

1956 ◽  
Vol 47 (4) ◽  
pp. 631-644 ◽  
Author(s):  
K. S. Hocking ◽  
D. Yeo
Keyword(s):  
Land Development ◽  
Small Population ◽  
Tsetse Flies ◽  
Treatment Level ◽  
Glossina Morsitans ◽  
Treated Area ◽  
Pre Treatment ◽  
Coarse Aerosol ◽  
Savannah Woodland ◽  
Mass Median

Two experiments are described where applications of coarse aerosols have been made to areas of savannah woodland infested with tsetse flies (Glossina spp.).The applications were made at nominal dosages of 0·25 gallons per acre, which was equivalent to either 0·20 lb. of p.p′DDT per acre, or 0·03 lb. of γ BHC per acre. The coarse aerosols had mass median diameters of approximately 60 microns.In one experiment, carried out at Urambo, Tanganyika, a reduction of 95 per cent, was obtained in populations of G. morsitans Westw. This kill was somewhat lower than in many other experiments, a fact that can be attributed mainly to our inability to maintain the cycle of applications. Immigration of flies into the treated area caused a relatively rapid increase in fly numbers to levels comparable to the pre-treatment populations, and in this respect the experiment was a failure.The other experiment, in Lango County, Uganda, was highly successful, and reduced a population of G. morsitans to 0·05 per cent, of its pre-treatment level, and eradicated a small population of G. pallidipes Aust. It is indeed likely that no stable population now exists in the area, and that the very few flies caught there since the end of the applications have been wanderers from other infested woodland. The continued success of the experiment is considered to be due to the effective isolation of the area.Some brief comments are made upon the costs of the method, and on its value under conditions of land development in Africa.

Aircraft Applications of Insecticides in East Africa. X.—An Investigation of the Behaviour of coarse Aerosol Clouds in Woodland

1956 ◽  
Vol 47 (3) ◽  
pp. 495-524 ◽  
Author(s):  
G. F. Burnett ◽  
B. W. Thompson
Keyword(s):  
Large Scale ◽  
Atmospheric Stability ◽  
Application Rate ◽  
Tsetse Flies ◽  
Control Procedure ◽  
Atmospheric Conditions ◽  
Degree Of Protection ◽  
Open Country ◽  
Coarse Aerosol ◽  
High Winds

In connection with studies on the control of tsetse flies (Glossina spp.) by insecticides, an investigation was made in Tanganyika Territory of the influence of a number of factors on the distribution of insecticide in woodland and open country. A solution of DDT in oil was disseminated as a coarse aerosol from an aircraft and its behaviour traced by the mortality suffered by caged flies. The test insects were wild-caught Musca (Eumusca) lusoria Wied., which proved more susceptible to the insecticide used than did Glossina. palpalis fuscipes Newst.In open country, complete kills were obtained with the standard application rate (defined as one run using 10 gals, per minute of a 10 per cent, solution of DDT) for at least three hundred yds. downwind of the line of emission, in all the atmospheric conditions encountered.Tests of the possibility of treating very thin woodland in comparatively high winds (for aerial dispersals of aerosols) and slightly unstable conditions were spoilt by variations in the emission rate of the insecticide, but it was shown that quite small numbers of twigs upwind provided a considerable degree of protection to the test insects and that the kills in cages completely exposed on the upwind side of trees were considerably less than at corresponding distances downwind in completely open country. There was evidence that in high winds and slightly unstable conditions, penetration through the trees was better than with moderate winds and small inversions, but in both conditions there was mortality behind obstacles.Preliminary comparisons between the kill in the open and in continuous woodland composed of Acacia xanthophloea showed that in the latter mortality was greatly reduced and did not approach that frequently obtained in practical large-scale experiments in tsetse control. A search was made for factors which would increase the level of mortality.Increased atmospheric stability caused greater average mortality at the expense of evenness of kill. This was not due solely to decreasing effective swathe width due to lighter winds.Large natural openings in the canopy assisted the penetration of insecticide in unstable conditions, but in stable air the kill around and downwind of clearings was reduced compared with kills in unbroken woodland.The principal factor in raising mortality to a generally high level was the summation of sublethal doses due to drifting downwind of the fringes of successive parallel swathes. The highest kill obtained in any of these trials was from summation of three swathes emitted 75 yds. apart, which produced a mean mortality of 84 per cent, for 75 yds. downwind of the third run.An attempt to cover the whole area of woodland by emitting insecticide in a series of parallel runs, as in actual control procedure, showed that in conditions of low turbulence there yet may be great unevenness in the kill obtained. Mortality varied between 21 and 100 per cent., and this irregularity was almost certainly due to the fact that during each of the runs the wind was almost directly along the aircraft track. Such contingencies are unavoidable, for unsteadiness of wind direction is a constant feature of the stable, non-turbulent conditions in the free air that are needed to permit any substantial kill within continuous woodland.The relation between these results and those obtained in practical control experiments is discussed. It is concluded that the use of caged insects and a particular type of woodland probably accounts for the comparatively low kills obtained in this investigation, from which, nevertheless, valid conclusions can be drawn concerning the variation in mortality from place to place.

scholarly journals Sources apportionment of fine and coarse aerosol in Klang Valley, Kuala Lumpur using positive matrix factorization

2011 ◽  
Vol 2 (2) ◽  
pp. 197-206 ◽  
Author(s):  
Shamsiah Abdul Rahman ◽  
Mohd Suhaimi Hamzah ◽  
Abdul Khalik Wood ◽  
Md Suhaimi Elias ◽  
Nazaratul Ashifa Adullah Salim ◽  
...  
Keyword(s):  
Matrix Factorization ◽  
Positive Matrix Factorization ◽  
Kuala Lumpur ◽  
Positive Matrix ◽  
Sources Apportionment ◽  
Klang Valley ◽  
Coarse Aerosol
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