Documents diesel engine 53 results

"Diesel engine exhaust is a complex mixture of gaseous and particulate compounds produced during the combustion of diesel fuels. The gas phase includes carbon dioxide, nitrogen oxides (NOX), carbon monoxide and small amounts of sulphur dioxide and various organic compounds. Diesel exhaust particles (DEP) contain elemental carbon (EC), organic compounds, sulphates, nitrates and trace amounts of metals and other elements. New technology diesel engines are characterised by a significant reduction of the DEP mass emissions. Occupational exposure to diesel exhaust occurs in mining, construction work, professional driving, agri-culture and other activities where diesel-powered vehicles and tools are applied. The critical health effects of diesel exhaust are considered to be pulmonary inflammation and lung cancer. For older technology diesel engines, pulmonary inflammatory responses were observed in human volunteers after single exposure at 100
g DEP/m3 (~ 75
g EC/m3), and in rats after long-term exposure at 210
g DEP/m3 (~ 160
g EC/m3). Development of lung tumours was seen in rats at 2 200
g DEP/m3 (~ 1 650
g EC/m3). For new technology diesel engines, pulmonary inflammatory changes were reported in rats after 13 and 130 weeks of exposure at 3.6 and 4.2 ppm NO2 (12–13
g DEP/m3, ~ 3
g EC/m3). The effect was absent at 0.9–1.0 ppm NO2 (4–5
g DEP/m3, ~ 1
g EC/m3). No indication of tumour development was detected. Epidemiological studies associate occupational exposure to exhaust from older technology diesel engines with increased lung cancer risk. Based on a log-linear meta-regression model, 45 years of occupational exposure to diesel exhaust at 1, 10 and 25
g EC/m3 was estimated to result in 17, 200 and 689 extra lung cancer deaths per 10 000 individuals, respectively, by the age of 80 years. Although data allowing a direct comparison of the carcinogenic potential of exhaust from new and older technology diesel engines are not available, the significant reduction of the DEP mass concentration in the new technology diesel engine exhaust is expected to reduce the lung cancer risk (per kWh). In addition to the critical effects, human and animal inhalation studies associate exposure to older technology diesel engine exhaust with sensory irritation, increased airway resistance, cardiovascular effects, genotoxicity and adjuvant allergenic effects. There are also animal studies indicating neuroinflammatory effects, developmental effects and effects on the male reproductive function. When evaluating the health risk of diesel exhausts it is important to take into account that the transition from “old” to “new” technology diesel engines is expected to take a long time. Keywords: cancer, cardiovascular, diesel engine, diesel exhaust, elemental carbon, inflammation, nitrogen dioxide, occupational exposure limit, particles, pulmonary, review, risk assessment, toxicity."

"Diesel engine exhaust fumes are a mixture of gases, vapours, liquid aerosols and particles created by burning diesel fuels. Diesel fumes may contain over 10 times the amount of soot particles than in petrol exhaust fumes, and the mixture includes several carcinogenic substances, meaning they have the potential to cause cancer. Breathing in high quantities of diesel exhaust fumes can cause irritation in the respiratory tract within a few minutes of exposure, but prolonged exposure over many years may be more harmful. The health effects will depend on the type and quality of diesel fuel being used (for example, whether it's low sulphur), the type and age of the engine, where and how it's used and maintained, and whether a combination of different diesel-powered engines are contributing to overall exposure."

"Diesel engine exhaust is a complex mixture of particles and gasses. If you work around diesel engines you can see and smell the exhaust and so it is immediately apparent when you are exposed to these high concentrations. However, the exhaust emissions disperse into the surrounding air and are no longer easily detected, but this does not mean that there is no risk; low levels of diesel engine exhaust can still increase your risk for cancer and other serious diseases."

"Conflicting evidence on the carcinogenicity of diesel exhaust (DE) and coal mine dust in occupational settings exist. Exposure measurement in most studies is inferred on the basis of job classifications and may lead to misclassification. Confounding behavioral factors (i.e., smoking) and occupational risk factors (exposure to asbestos, arsenic, radon) need to be considered. We evaluated the epidemiological evidence and current findings of the carcinogenicity of DE and coal mine dust in occupational settings. Pertaining literature was identified through Medline search and recent review articles. Strengths and limitations of recent approaches are discussed. Many epidemiological studies have addressed the question of carcinogenicity in workers exposed to DE, and most showed a low-to-medium increase in the risk of bronchial carcinoma. The pooled relative risk (RR) estimates lie between 1.33 and 1.47, and a consistent rise in risk across various job categories and study designs point to a causal relationship. Data on the carcinogenicity of coal mine dust are less consistent and the potential for confounding by unmeasured risk factors (arsenic, radon, DE) are higher. While silica as one of its components has been evaluated as carcinogenic, there is inadequate evidence for the carcinogenicity of pure coal dust according to the International Agency for Research on Cancer (IARC).There is sufficient evidence for a causal relationship between DE and lung cancer in occupational settings. The evidence for coal mine dust is less convincing, but individual studies show an increase in risk of lung cancer in exposed workers."

"Objectives:To begin to elucidate the mechanisms of particle toxicity to the lung, the bioreactivity of four carbon black (CB) and diesel exhaust particles ((DEPs), a surrogate for particulate matter of aerodynamic diameter <10 m (PM[10]), were examined with primary cultures of Clara and type II epithelial cells. Methods:The particles were extensively characterised by surface chemistry, size, and aggregation properties. Toxicity of the particles was assessed by determining cell attachment to an extracellular matrix substratum.Results:The spherulite size range for the particles ranged from 50, 40, 20, 20, and 30 nm for CB1-4 and DEPs. All particle samples had different surface chemical compositions. CB1 was the least toxic to Clara (170 g) and type II cells (150 g) and CB4 was the most toxic (55 g and 23 g respectively). DEPs stored for 2 weeks were equally toxic to both epithelial cell types (27-28 g). DEPs became progressively less toxic to type II cells with time of storage. Both primary epithelial cell types internalised the particles in culture.Conclusions:Bioreactivity was found to be related to CB particle spherulite size and hence surface area: the smaller the particle and larger the surface area, the more toxic the particles. Also, CB particles with the most complicated surface chemistry were the most bioreactive. Freshly prepared DEPs were equally toxic to type II and Clara cells and they became progressively less toxic to the type II cells with time. With all CB and DEPs, the primary epithelial cells internalised the particles, although this was noted most in cells of low functional competence."

This study reviews 3498 male cases of lung cancer in relation to occupation and diesel exhaust emissions exposure. Drivers of trucks, buses, taxis, diesel locomotives and forklift trucks, bulldozers, graders, excavators, and tractors, were considered as exposed to diesel fumes and their cumulative exposure was estimated. Results of this study provide further evidence that occupational exposure to diesel motor emissions is associated with an increased lung cancer risk.