作者：
Arthur, Frank H.ARS
USDA Ctr Grain & Anim Hlth Res Manhattan KS 66502 USA
The fumigant methyl bromide (MB) is being phased out of production and usage to control stored-product insects in flour and rice mills, as well as feed and food production plants, in the United States and other develo...
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The fumigant methyl bromide (MB) is being phased out of production and usage to control stored-product insects in flour and rice mills, as well as feed and food production plants, in the United States and other developed countries throughout the world. A phase-out schedule has also been established for undeveloped counties under a delayed timeline compared to the one established for developed countries. Whole-plant alternatives to MB treatment, such as the fumigant sulfuryl fluoride and heat, can be used in place of MB, but they have some limitations as well, which will be briefly discussed in this review. Hence, residual surface treatments with contact insecticides and insect growth regulators and aerosol applications are receiving increased attention for incorporation into management programs that historically relied on MB fumigations. This review will focus on recent research with contact insecticides and aerosols for controlling stored-product insects in structures and how they can be viewed as options for control to alleviate concerns regarding the phase-out and reduced availability of MB for structural fumigations. A brief discussion of emerging pest species or groups, and how they can be controlled with surface treatments and aerosols, is also included in the review.
Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public ***,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of 2015–2019 ...
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Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public ***,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of 2015–2019 over NCP via 8 scenarios with WRF-Chem *** simulated mean MDA8 O_(3) in urban areas of 13 major cities in NCP increased by 17.1%∼34.8%,which matched well with the observations(10.8%∼33.1%).Meanwhile,the model could faithfully reproduce the changes in aerosol loads,precursors,and meteorological conditions.A relatively-even O_(3) increase(+1.2%∼+3.9%for 24-h O_(3) and+1.0%∼+3.8%for MDA8 O_(3))was induced by PM_(2.5) dropping,which was consistent with the geographic distribution of regional PM_(2.5) ***,the NO_(2) reduction coupled with a nearconstant VOCs led to the elevated VOCs/NOx ratios,and then caused O_(3) rising in the areas under VOCs-limited ***,the pronounced increases occurred in Handan,Xingtai,Shijiazhuang,Tangshan,and Langfang(+10.7%∼+13.6%for 24-h O_(3) and+10.2%∼+12.2%forMDA8 O_(3));while the increases in other citieswere 5.7%∼10.5%for 24-h O_(3) and 4.9%∼9.2%for MDA8 O_(3).Besides,the meteorological fluctuations brought about the more noticeable O_(3) increases in northern parts(+12.5%∼+13.5%for 24-h O_(3) and+11.2%∼+12.4%for MDA8 O_(3))than those in southern and central parts(+3.2%∼+9.3%for 24-h O_(3) and+3.7%∼+8.8%for MDA8 O_(3)).The sum of the impacts of the three drivers reached 16.7%∼21.9%,which were comparable to the changes of the observed O_(3).Therefore,exploring reasonable emissionsreduction strategies is essential for the ozone pollution mitigation over this region.
Under the effects of electric field and chemical reaction, the problem of dispersion of aerosols in a poorly conducting fluid in a channel is solved analytically using the mixture theory together with a regular pertur...
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Under the effects of electric field and chemical reaction, the problem of dispersion of aerosols in a poorly conducting fluid in a channel is solved analytically using the mixture theory together with a regular perturbation technique. It is shown that the aerosols are dispersed relative to a plane moving with the mean speed of atmospheric fluid as well as the mean speed of agglomeration of aerosol with a relative diffusion coefficient, called the Taylor dispersion coefficient. This coefficient is numerically computed and the results reveal that it increases with an increase in the electric number, but decreases with increasing porous parameter. The physical explanations for the phenomena are given in this article.
A hygroscopic tandem differentialmobility analyser(H-TDMA)was used to observe the sizeresolved hygroscopic characteristics of submicron particles in January and April 2018 in urban *** probability distribution of the ...
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A hygroscopic tandem differentialmobility analyser(H-TDMA)was used to observe the sizeresolved hygroscopic characteristics of submicron particles in January and April 2018 in urban *** probability distribution of the hygroscopic growth factor(HGF-PDF)in winter and spring usually showed a bimodal pattern,with more hygroscopic mode(MH)being more *** seasonal variation in particle hygroscopicity was related to the origin of air mass,which received polluted southerly air masses in spring and clean northwesterly air masses in *** showed stronger hygroscopic behaviour during heavy pollution episodes(HPEs)with elevated concentrations of secondary aerosols,especially higher mass fraction of nitrate,which were indicated using the PM2.5(particulate matter with diameter below 2.5μm)mass concentration normalised by CO mass *** hygroscopic parameter(κ)values were calculated using H-TDMA(κhtdma)and chemical composition(κchem).The closure study showed thatκchem was overestimated in winter afternoon when compared withκhtdma,because the organic particle hygroscopic parameter(κorg)was overestimated in the *** was influenced by the presence of a high concentration of hydrocarbon-like organic aerosol(HOA)with a weak water uptake ability.A positive relationship was observed betweenκorg and the ratio of oxygenated organic aerosol(OOA)and HOA,thereby indicating that the strong oxidation state enhanced the hygroscopicity of the *** study revealed the effect of local emission sources and secondary aerosol formation processes on particle hygroscopicity,which is of great significance for understanding the pollution formation mechanism in the North China Plain.
The coronavirus disease 2019(COVID-19)pandemic caused by frequently mutating severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has had a worldwide ***,detailed data on the potential aerosol transmission of SA...
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The coronavirus disease 2019(COVID-19)pandemic caused by frequently mutating severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has had a worldwide ***,detailed data on the potential aerosol transmission of SARS-CoV-2 in real-world and controlled laboratory settings remain *** the COVID-19 pandemic in Shanghai,China in 2022,samples were collected in a Fangcang shelter hospital,a large-scale temporary hospital rapidly built by converting the existing National Exhibition and Convention Center(Shanghai)into a health care *** samples at different sites and intervals around patients and in public areas,surface samples,and pharyngeal swab samples from corresponding patients were *** were tested for SARS-CoV-2 using real-time quantitative polymerase chain reaction(RT-qPCR)assays,followed by sequencing if the cycle threshold(Ct)value was<*** positivity rate for SARS-CoV-2 in aerosol samples was high in contaminated zones(37.5%,104/277),especially around the bed(41.2%,68/165)and near ventilation inlets(45.2%,14/31).The prevalence of SARS-CoV-2 around the bed,public areas,and air inlets of exhaust vents fluctuated and was closely related to the positivity rate among patients at corresponding sampling *** surface samples of different personal protective equipment from medical staff had high positivity *** sequences of joined ORF1ab and spike genes obtained from sixty samples represented two main clusters of Omicron *** was consistency in virus sequences from the same patient and their environment,and the detected virus sequences matched those of virus strains in circulation during the collection periods,which indicated a high likelihood of cross-contamination in the Fangcang shelter *** summary,the results provide a quantitative and real landscape of the aerosol transmission of SARS-CoV-2 and a patient-centered view of contamination in large and enclosed spaces and offer a useful guid
Calculations indicate that aerosols are not directly responsible for the present increase in ice abundance in the Northern Hemisphere. Indeed it appears that aerosols cause heating of the atmosphere near the poles. Th...
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Calculations indicate that aerosols are not directly responsible for the present increase in ice abundance in the Northern Hemisphere. Indeed it appears that aerosols cause heating of the atmosphere near the poles. The present background aerosol density at 85°S latitude causes a temperature increase of ∼ 0.2°K, while that at 85°N causes an increase of ∼ 0.05°K.
Aerosol samples collected from the April 17, 1979 eruption plume of Soufrier, St. Vincent, at altitudes betlow 1.8-5.5 km were physically and chemically similar to the ash that fell on the island. Higher altitude samp...
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Aerosol samples collected from the April 17, 1979 eruption plume of Soufrier, St. Vincent, at altitudes betlow 1.8-5.5 km were physically and chemically similar to the ash that fell on the island. Higher altitude samples (7.3 and 9.5 km) had a lower ash contents but comparable concentrations of sulfate, which were above the background concentration found at these altitudes.
The mass concentration and size distribution of aerosols in Tokaimura were investigated using a high-volume and a low-volume Andersen sampler. A difference was found using the two samplers： the concentration of total...
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The mass concentration and size distribution of aerosols in Tokaimura were investigated using a high-volume and a low-volume Andersen sampler. A difference was found using the two samplers： the concentration of total aerosols determined with the high-volume sampler is smaller than that of the low-volume sampler by 70-90% throughout the year. Compared to the high-volume sampler, low-volume sampler gave lower concentration for aerosols 〉7 μm, higher concentration for aerosols of 3.3-7.0 μm and 〈 1.1 μm, though similar results for aerosols of 1.1-3.3 μm. The low-volume sampler was found to have better separation efficiency and higher accuracy.
Two air ingress tests (AIT) were performed to model a severe reactor accident. Some modifications of the test conditions were done in second test compared with the first test. The morphological features and the elemen...
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Two air ingress tests (AIT) were performed to model a severe reactor accident. Some modifications of the test conditions were done in second test compared with the first test. The morphological features and the elemental composition of the aerosol particles were studied to compare with the ones collected in the first test.
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