Responses of secondary aerosols to relative humidity and photochemical activities in an industrialized environment during late winter

2018 ◽  
Vol 193 ◽  
pp. 66-78 ◽  
Author(s):  
Yangzhou Wu ◽  
Xinlei Ge ◽  
Junfeng Wang ◽  
Yafei Shen ◽  
Zhaolian Ye ◽  
...  
2020 ◽  
Vol 222 (4) ◽  
pp. 564-571 ◽  
Author(s):  
Michael Schuit ◽  
Shanna Ratnesar-Shumate ◽  
Jason Yolitz ◽  
Gregory Williams ◽  
Wade Weaver ◽  
...  

Abstract Aerosols represent a potential transmission route of COVID-19. This study examined effect of simulated sunlight, relative humidity, and suspension matrix on stability of SARS-CoV-2 in aerosols. Simulated sunlight and matrix significantly affected decay rate of the virus. Relative humidity alone did not affect the decay rate; however, minor interactions between relative humidity and other factors were observed. Mean decay rates (± SD) in simulated saliva, under simulated sunlight levels representative of late winter/early fall and summer were 0.121 ± 0.017 min−1 (90% loss, 19 minutes) and 0.306 ± 0.097 min−1 (90% loss, 8 minutes), respectively. Mean decay rate without simulated sunlight across all relative humidity levels was 0.008 ± 0.011 min−1 (90% loss, 286 minutes). These results suggest that the potential for aerosol transmission of SARS-CoV-2 may be dependent on environmental conditions, particularly sunlight. These data may be useful to inform mitigation strategies to minimize the potential for aerosol transmission.


2007 ◽  
Vol 97 (3) ◽  
pp. 352-358 ◽  
Author(s):  
V. Rossi ◽  
M. Bolognesi ◽  
S. Giosuè

The dynamics of the inoculum of Taphrina deformans were studied during a 4-year period by (i) inspecting curled leaves for the presence of asci, (ii) placing deposition spore samplers within the tree canopies, and (iii) exposing potted peach plants (trap plants). These three approaches produced consistent results. Four main periods characterized the dynamics of the inoculum: the first period coincides with the parasitic stage of the pathogen's life cycle and the other periods with the saprophytic stage. Mid- to late spring (first period) was characterized by the presence of asci on infected leaves which produced and ejected large quantities of ascospores in 96% of the samplings. Rainfall was not necessary for ascospore dispersal, which was favored by air temperature <20°C and relative humidity ≥80% or wetness duration >8 h. In summer and autumn (second period), blastospores were trapped in 54 and 24% of samplings, respectively, with low spore numbers. In the winter (third period), blasto-spores were trapped in the lowest numbers and in only 6% of samplings. In late winter to early spring (fourth period), blastospores were found in 56% of samples, with increasing numbers. Rainfall significantly influenced blastospore dispersal and temperature was correlated with the seasonality found during the saprophytic stage.


2019 ◽  
Vol 29 (57) ◽  
pp. 583-608
Author(s):  
Diego Nascimento ◽  
Luan Victor Lima ◽  
Vitor Cruz

Sob a abordagem da climatologia geográfica, que leva em consideração a dinâmica das massas de ar na análise do ritmo e da gênese do clima, o presente trabalho busca apresentar os episódios de eventos climáticos extremos ocorridos em Goiânia-GO e abordar os mecanismos atmosféricos responsáveis pela gênese dos mesmos. Os eventos extremos foram levantados a partir de dados diários precipitação, temperatura máxima e mínima e umidade relativa do ar, registrados pela estação meteorológica do Instituto Nacional de Meteorologia (INMET), compreendendo a série temporal de 1961 a 2018 (58 anos). A identificação dos mecanismos atmosféricos atuantes nos dias dos episódios extremos foi realizada a partir da leitura e interpretação de cartas sinóticas da Marinha do Brasil, tendo como base o recorte temporal de 2012 a 2018. Foi possível apontar a ocorrência de eventos extremos em períodos específicos do ano, como no caso de eventos de precipitação no verão, sob influência da Massa equatorial continental e da Zona de Convergência do Atlântico Sul; de temperatura máxima no final do inverno e início da primavera, quando predomina a Massa equatorial continental e a Massa tropical Atlântica; de temperatura mínima no outono e inverno, condicionados pela incursão da Massa polar; de umidade relativa do ar no inverno, ocorrendo devido a atuação dos sistemas atmosféricos que habitualmente definem a condição sinótica em Goiânia.Palavras–chave: eventos extremos, massas de ar, fatores, mecanismos, impactos.Abstract Under the approach of Geographical Climatology, which takes into account the dynamics of the air masses in the analysis of the rhythm and the genesis of the climate, the present work seeks to present the episodes of extreme climatic events occurring in Goiânia-GO and to indicate the atmospheric mechanisms responsible for the genesis of this events. The extreme events were listed from daily precipitation, maximum and minimum temperature and relative humidity data, recorded by the meteorological station of the National Institute of Meteorology, comprising the time series from 1961 to 2018 (58 years). The identification of the atmospheric mechanisms acting on the days of the extreme episodes was performed from the reading and interpretation of Brazilian Navy's synoptic charts, based on the temporal cut from 2012 to 2018. It was possible to indicate the occurrence of extreme events in specific periods of the year, as in the case of summer precipitation events, under the influence of Continental equatorial mass and South Atlantic Convergence Zone; of maximum temperature in late winter and early spring, when Continental equatorial mass and Atlantic tropical mass predominate; of minimum temperature in autumn and winter, conditioned by the incursion of Polar mass; of relative humidity of the air in the winter, occurring due to the performance of the atmospheric systems that habitually define the synoptic condition in Goiânia.Keywords: extreme events, air masses, factors, mechanisms, impacts


1997 ◽  
Vol 87 (1) ◽  
pp. 55-59 ◽  
Author(s):  
A. A. Guglielmone ◽  
O. S. Anziani ◽  
A. J. Mangold ◽  
R. E. Giorgi ◽  
M. M. Volpogni ◽  
...  

AbstractThe seasonal variation of adult populations of Haematobia irritans Linnaeus was monitored at Santa Fe, Argentina from August 1992 to August 1994 by weekly counts of flies on grazing heifers. Each year, flies were recorded at a density of more than two flies per heifer from August/September to the following June, with peaks of abundance in mid to late spring and late summer to mid autumn. The seasonal trend of fly numbers was best correlated with the mean temperature 4 weeks prior to each fly count (correlation indices of P<0.01 in six of the nine fly periods) followed by the previous 4 week mean saturation deficit. Rainfall and relative humidity correlated poorly with the seasonality of H. irritans. Temperature appeared crucial at the beginning (late winter) and at the end (early-mid autumn) of the fly season while its relevance diminished in the middle of the season. The percentage of heifers that were infested decreased from 80–100% in the fly season to 0–55% between fly seasons but H. irritans never disappeared from the heards, indicating that if diapause occurs at the latitude of the study area, part of the fly population was not sensitive to diapause inducing factors.


2018 ◽  
Vol 24 (1) ◽  
Author(s):  
LAKSHMI CHOUDHARY ◽  
PRABHAWATI PRABHAWATI

Prevalence of soil transmitted helminthes infections in apparently healthy school going children and other 528 people of different districts of Koshi regions of North Bihar were evaluated. Over all incidences of STHs infection was 39.39% during study. High incidence of STH was seen in the rainy season i.e., in the month of July and August, September, significantly higher (P<0.05) .The incidence of Ascaris lumbricoides was highest in the month of August (18.64%). The month of September was 15.25% followed by that of July (14.4%) and October with 10.16%. Also the incidence of hookworm registered the highest incidence in the month of June (19.27%) and lowest in the month of December (4.82%) during the study period. However prevalence of Trichuris trichiura was negligible and it was almost nil in the most of the months but was highest in month of September with 28.57% and lowest in October with 14.00% The climatic factors are responsible for soil transmitted helminthes which are temperature, rainfall and relative humidity. Ascariasis, Trichuriasis and Ancyclostomiasis (Hookworm infection) are found to be endemic in this region.


2019 ◽  
Vol 25 (1) ◽  
Author(s):  
MASROOR ALI KHAN ◽  
KHALID AL GHAMDI ◽  
JAZEM A. MEHYOUB ◽  
RAKHSHAN KHAN

The focus of this study is to find the relationship between El Nino and dengue fever cases in the study area.Mosquito density was recorded with the help of light traps and through aspirators collection. Climate data were obtained from National Meteorology and Environment centre. (Year wise El Nino and La Nina data are according to NOAA & Golden Gate Weather Services). Statistical methods were used to establish the correlation coefficient between different factors. A high significant relationship was observed between Relative Humidity and Dengue fever cases, but Aedes abundance had no significant relationship with either Relative humidity and Temperature. Our conclusion is that the El Nino does not affect the dengue transmission and Aedes mosquito abundance in this region, which is supported by earlier works.


2007 ◽  
Vol 2007 (suppl_26) ◽  
pp. 417-422 ◽  
Author(s):  
W. Oueslati ◽  
M. S. Karmous ◽  
H. Ben Rhaiem ◽  
B. Lanson ◽  
A. Ben Haj Amara

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