[Exhaust Smoke of Non-Road Vehicles in Typical Cities of Eastern China]

In typical cities of East China, more than 900 non-road vehicles were tested for exhaust smoke. Based on the investigation of the properties of these non-road vehicles, exhaust smoke intensities for different kinds of non-road vehicles are recommended. We also quantitatively study the differences in smoke intensity among vehicle age, vehicle power, test conditions, and fuels. The results showed that smoke intensity of non-road vehicles was (1.02±0.57) m^-1 and that Ringelmann smoke was 2.10±0.19. In comparison to Chinese national standard (GB 36886), approximately 12%-25% of tested non-road vehicles' smoke intensity exceeded the standard limit. The smoke intensity of 80% of tested non-road vehicles was higher during start-up than under free acceleration. In comparison to ordinary diesel, the smoke intensities of tested non-road vehicles that used automotive diesel were lower. The instantaneous increase in fuel injection during start-up, as well as poor fuel quality, can directly affect the exhaust smoke of non-road vehicles.

[Treatment Status and Emission Characteristics of Volatile Organic Compounds from Typical Industrial Sources]

The status of treatment equipment, the emission characteristics, and the ozone formation potential (OFP) of volatile organic compounds (VOCs) for 11 typical enterprises, which were categorized into the 8 major VOC emission industries identified by the emission inventory of a typical city in the Yangtze River Delta, are discussed in this paper. There was a large difference in the removal efficiency of non-methane hydrocarbon (NMHC) between different treatment techniques, and even an increase in concentration occurred after some of the treatments. The current treatment equipment for VOCs needs further optimization. The emissions of NMHC, benzene, toluene, and xylene in most of the surveyed enterprises exceeded their corresponding standards, with toluene the worst offender. The most abundant compounds in the eight emission industries were aromatic hydrocarbons and oxygenated VOCs, whereas aromatic hydrocarbons contributed the most to ozone formation potential. There were large differences in emission characteristics of VOCs from different industries. Priority should be placed on the industries that have large OFP when control strategies of VOCs are considered.

[Emission Inventory and Pollution Characteristics of Industrial VOCs in Hangzhou, China]

For the 2022 Asian Games, a series of major events were held in Hangzhou City in 2016 at the international summit, where research on VOC emission inventories, especially on industrial VOCs, has attracted the attention of local residents and management departments. By taking a bottom-up approach, 3518 enterprises in more than 30 industries in Hangzhou were investigated and an industrial VOCs emission inventory for Hangzhou was established. Based on the data on regional emissions, emissions intensity, and spatial distribution, the industrial VOCs emissions in Hangzhou were systematically analyzed. The VOC emissions from industrial sources in Hangzhou amounted to 36839.5 tons in 2015. Printing and reproduction of recorded media; chemical raw materials and chemical products manufacturing; and the metal, textile, rubber, and plastics products industries were the most important sources of industrial VOC emissions in Hangzhou. The largest industrial VOC emissions were measured in Xiaoshan District, followed by Fuyang District and Dajiangdong Industrial Agglomeration Area. The highest VOC emissions intensity was detected in Fuyang District, Jiande City, and Lin'an City. Industrial VOC emissions were mainly concentrated in more intensive industrial areas in Xiaoshan, Fuyang, Yuhang, and Dajiangdong Districts.

[Air Pollutant Emission Inventory of Non-road Machineries in Typical Cities in Eastern China]

Based on site investigation of non-road vehicles in Shanghai and Hangzhou located in east China, non-road vehicle emission inventory in 2014 was established in these cities as well as its emission inventory technology. Characteristics of non-road vehicle were also analyzed, including classification, type of fuel, power and emission standard. The results showed that diesel consumed by non-road vehicles was 6.1×10⁵ t in Shanghai and 3.2×10⁵ t in Hangzhou; NO_x emission was 3.09×10⁴ t in Shanghai and 1.72×10⁴ t in Hangzhou; PM_2.5 emission was 1.41×10³ t in Shanghai and 8.1×10² t in Hangzhou, 2014. Emissions from excavators and other construction equipment contributed the most in non-road vehicle emission inventory. Non-road vehicle has become one of the important sources of urban air pollution, whose NO_x emissions accounted for 11.1% of all urban sources in Shanghai and 16.1% in Hangzhou, and accounted for 18.5% of mobile sources in Shanghai and 32.2% in Hangzhou.

Coronary artery stenoses: a phantom study using contrast enhanced three-dimensional electron beam tomography

This paper evaluated the accuracy of electron beam tomographic angiography (EBA) with conventional coronary arteriography (CCA) using four graded artificial stenoses in a postmortem swine coronary phantom model. The sensitivity, specificity, and accuracy of EBA for diagnosing significant stenosis (> or =50% stenosis) were 94.3%, 96.7%, and 95.8%, respectively. The diagnostic accuracy of EBA had no significant difference with CCA (chi(2)=0.0162; P>.05). EBA three-dimensional (3D) procedures had high interobserver reproducibility (k=.92-.95, P>.05). Maximum intensity projection (MIP) was the most sensitive and curved planar reformation (CPR) was the most accurate 3D procedure for quantitatively identifying coronary stenosis. EBA yields promising results concerning the visualization of coronary artery stenosis with high accuracy for stenoses >50%.

Electron beam tomography with three-dimensional reconstruction in the diagnosis of aortic diseases

BACKGROUND

This study was performed to evaluate the protocols of electron beam tomographic angiography and three-dimensional reconstruction for assessing the diagnostic value of aortic diseases.

METHODS

EXPERIMENTAL DESIGN

Retrospective and comparative study.

SETTINGS

University hospital.

PATIENTS

Between 1996 and 1998, 189 cases who underwent electron beam tomographic angiography and diagnosed with aortic diseases were analyzed retrospectively. The results were compared with surgical and pathological findings in 68 cases. Electron beam tomographic angiography was used single-slice-scanning with ECG-triggering for screening of the thoracic aorta, continuous-volume-scanning, permitted by continuous X-ray exposure with table incremention, was performed for the abdominal aorta scanning without ECG-triggering. Three-dimensional reconstructions were performed with shaded-surface display, multiplanar reformatting and/or maximum intensity projection methods.

RESULTS

Electron beam tomography angiography with ECG-triggered sections of single-slice-scanning improved the image quality of the ascending aorta without motion artifacts. Continuous-volume-scanning was suitable for screening of the abdominal aorta because of minimizing exposure time (10-14 sec) and saving contrast media (total contrast material of 45.5+/-6.6 ml was needed). One hundred eighty-nine cases were diagnosed with aortic dissection (97 cases), aortic aneurysm (26 cases), pseudoaneurysm (8 cases), Marfan's syndrome (39 cases), Takayasu's arteritis (5 cases) and congenital aortic malformations (14 cases). Electron beam tomography results were compared with the findings of surgery (as gold standard) in 68 cases, the diagnostic accuracy was 97% (2 cases with aortic aneurysm were erroneously diagnosed with pseudoaneurysm).

CONCLUSIONS

Electrocardiographically triggered, contrast-enhanced electron beam tomography is feasible for the diagnosis of all kinds of aortic diseases, with excellent three-dimensional images competitive in quality with conventional selective aortic angiography or digital subtraction angiography.

Evaluation of coronary artery bypass graft patency using three-dimensional reconstruction and flow study on electron beam tomography

OBJECTIVES

To establish and evaluate two protocols for the noninvasive visualization and assessment of coronary artery bypass graft (CABG) patency on electron beam tomography (EBT).

METHODS

Two hundred fourteen consecutive patients who underwent CABG surgery were scanned using both EBT angiography with three-dimensional reconstruction and EBT flow study with time-density curve analysis.

RESULTS

There was a total of 589 CABGs evaluated in this study (10 grafts were excluded because of artifacts); 133 (98.5%) of 135 arterial grafts were patent, 345 (77.7%) of 444 saphenous vein grafts were patent. Within 5 years or 5-10 years after surgery, arterial graft patency exceeded venous graft patency (p<0.001). Three-dimensional EBT angiography achieved higher sensitivity, specificity, and accuracy (97.7%, 94.1%, and 96.7%, respectively) than EBT flow study (88.4%, 82.4%, and 85.2%, respectively) for evaluating occlusion or patency of CABGs. The intragraft flow of patent arterial and venous grafts were 4.9+/-2.2 ml/min/g and 6.9+/-2.8 ml/min/g, respectively (p<0.001).

CONCLUSION

The combination of EBT three-dimensional reconstruction and flow study can be more effectively performed in the assessment of CABG anatomy and quantification of patent CABG flow.