D9017 The Durham Light Infantry(8190815683)

Diesel exhaust is the gaseous exhaust produced by a diesel type of

internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...

, plus any contained

particulates Particulates – also known as atmospheric aerosol particles, atmospheric particulate matter, particulate matter (PM) or suspended particulate matter (SPM) – are microscopic particles of solid or liquid matter suspended in the air. The ...

. Its composition may vary with the fuel type or rate of consumption, or speed of engine operation (e.g., idling or at speed or under load), and whether the engine is in an on-road vehicle, farm vehicle, locomotive, marine vessel, or stationary generator or other application. Diesel exhaust is a

Group 1 carcinogen A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic id ...

, which causes

lung cancer Lung cancer, also known as lung carcinoma (since about 98–99% of all lung cancers are carcinomas), is a malignant lung tumor characterized by uncontrolled cell growth in tissues of the lung. Lung carcinomas derive from transformed, malign ...

and has a positive association with

bladder cancer Bladder cancer is any of several types of cancer arising from the tissues of the urinary bladder. Symptoms include blood in the urine, pain with urination, and low back pain. It is caused when epithelial cells that line the bladder become ma ...

. It contains several substances that are also listed individually as human carcinogens by the IARC. Methods exist to reduce nitrogen oxides (NO_x) and particulate matter (PM) in the exhaust. So, while diesel fuel contains slightly more carbon (2.68 kg CO₂/litre) than petrol (2.31 kg CO₂/litre), overall CO₂ emissions of a diesel car tend to be lower due to higher efficiency. In use, on average, this equates to around 200 g CO₂/km for petrol and 120 g CO₂/km for diesel.

Composition

The primary products of petroleum fuel combustion in air are carbon dioxide, water, and nitrogen. The other components exist primarily from incomplete combustion and

pyrosynthesis {{Short pages monitor in PM emitted during hot idling were greater than those from cold idling; reasons for PM reduction in biodiesel emissions were suggested to result from the oxygenated structure of biodiesel fuel, as well as arising from changes in technology (including the use of a

catalytic converter A catalytic converter is an exhaust emission control device that converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction. Catalytic converters are usuall ...

in this test system). Other studies concluded that while in certain specific cases (i.e. low loads, more saturated feedstocks, ...), NOx emissions can be lower than with diesel fuel, in most cases NOx emissions are higher, and the NOx emissions even go up as more biofuel is mixed in. Pure biodiesel (B100) even ends up having 10-30% more NOx emissions compared to regular diesel fuel.

Specific effects

Exposures have been linked with acute short-term symptoms such as

headache Headache is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of depression in those with severe headaches. Headaches can occur as a resul ...

dizziness Dizziness is an imprecise term that can refer to a sense of disorientation in space, vertigo, or lightheadedness. It can also refer to disequilibrium or a non-specific feeling, such as giddiness or foolishness. Dizziness is a common medical ...

, light-headedness,

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. While not painful, it can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the ...

coughing A cough is a sudden expulsion of air through the large breathing passages that can help clear them of fluids, irritants, foreign particles and microbes. As a protective reflex, coughing can be repetitive with the cough reflex following three ph ...

, difficult or labored breathing, tightness of chest, and irritation of the eyes, nose, and throat. Long-term exposures can lead to chronic, more serious health problems such as

cardiovascular disease Cardiovascular disease (CVD) is a class of diseases that involve the heart or blood vessels. CVD includes coronary artery diseases (CAD) such as angina and myocardial infarction (commonly known as a heart attack). Other CVDs include stroke, ...

, cardiopulmonary disease, and

. Elemental

carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon makes ...

attributable to traffic was significantly associated with

wheezing A wheeze is a continuous, coarse, whistling sound produced in the respiratory airways during breathing. For wheezes to occur, some part of the respiratory tree must be narrowed or obstructed (for example narrowing of the lower respiratory tract ...

at age 1 and persistent wheezing at age 3 in the Cincinnati Childhood Allergy and Air Pollution Study birth cohort study. The NERC-HPA funded Traffic Pollution and Health in London project at King's College London is currently seeking to refine understanding of the health effects of traffic pollution. Ambient traffic-related air pollution was associated with decreased cognitive function in older men. Mortality from diesel soot exposure in 2001 was at least 14,400 out of the German population of 82 million, according to the official report 2352 of the ''Umweltbundesamt Berlin'' (Federal Environmental Agency of Germany). The study of nanoparticles and

nanotoxicology Nanotoxicology is the study of the toxicity of nanomaterials. Because of quantum size effects and large surface area to volume ratio, nanomaterials have unique properties compared with their larger counterparts that affect their toxicity. Of th ...

is in its infancy, and health effects from nanoparticles produced by all types of diesel engines are still being uncovered. It is clear, that diesel health detriments of fine particle emissions are severe and pervasive. Although one study found no significant evidence that short-term exposure to diesel exhaust results in adverse extrapulmonary effects, effects that are correlated with an increase in

, a 2011 study in ''

The Lancet ''The Lancet'' is a weekly peer-reviewed general medical journal and one of the oldest of its kind. It is also the world's highest-impact academic journal. It was founded in England in 1823. The journal publishes original research articles, ...

'' concluded that traffic exposure is the single most serious preventable trigger of

heart attack A myocardial infarction (MI), commonly known as a heart attack, occurs when blood flow decreases or stops to the coronary artery of the heart, causing damage to the heart muscle. The most common symptom is chest pain or discomfort which m ...

in the general public, as the cause of 7.4% of all attacks.: "Taking into account the OR and the prevalences of exposure, the highest PAF was estimated for traffic exposure (7.4%)... " :"... ds ratios and frequencies of each trigger were used to compute population-attributable fractions (PAFs), which estimate the proportion of cases that could be avoided if a risk factor were removed. PAFs depend not only on the risk factor strength at the individual level but also on its frequency in the community. ... e exposure prevalence for triggers in the relevant control time window ranged from 0.04% for cocaine use to 100% for air pollution. ... Taking into account the OR and the prevalences of exposure, the highest PAF was estimated for traffic exposure (7.4%) ... It is impossible to tell how much of this effect is due to the stress of being in traffic and how much is due to exposure to exhaust. Since the study of the detrimental health effects of nanoparticles (

) is still in its infancy, and the nature and extent of negative health impacts from diesel exhaust continues to be discovered, it remains controversial whether the public health impact of diesels is higher than that of petrol-fuelled vehicles.

Variation with engine conditions

The types and quantities of nanoparticles can vary according to operating temperatures and pressures, presence of an open flame, fundamental fuel type and fuel mixture, and even atmospheric mixtures. As such, the resulting types of

nanoparticle A nanoparticle or ultrafine particle is usually defined as a particle of matter that is between 1 and 100 nanometres (nm) in diameter. The term is sometimes used for larger particles, up to 500 nm, or fibers and tubes that are less than 10 ...

s from different engine technologies and even different fuels are not necessarily comparable. One study has shown that 95% of the volatile component of diesel nanoparticles is unburned lubricating oil. Long-term effects still need to be further clarified, as well as the effects on susceptible groups of people with cardiopulmonary diseases. Diesel engines can produce black soot (or more specifically diesel particulate matter) from their exhaust. The black smoke consists of carbon compounds that have not burned because of local low temperatures where the fuel is not fully atomized. These local low temperatures occur at the cylinder walls, and at the surface of large droplets of fuel. At these areas where it is relatively cold, the mixture is rich (contrary to the overall mixture which is lean). The rich mixture has less air to burn and some of the fuel turns into a carbon deposit. Modern car engines use a

diesel particulate filter A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine.Tom Nash (May 2003) "Diesels: The Smoke is clearing", ''Motor '' Vol.199 No. 5, p. 54, Hearst Business Publ ...

(DPF) to capture carbon particles and then intermittently burn them using extra fuel injected directly into the filter. This prevents carbon buildup at the expense of wasting a small quantity of fuel. The full load limit of a diesel engine in normal service is defined by the "black smoke limit", beyond which point the fuel cannot be completely burned. As the "black smoke limit" is still considerably lean of stoichiometric, it is possible to obtain more power by exceeding it, but the resultant inefficient combustion means that the extra power comes at the price of reduced combustion efficiency, high fuel consumption and dense clouds of smoke. This is only done in high performance applications where these disadvantages are of little concern. When starting from cold, the engine's combustion efficiency is reduced because the cold engine block draws heat out of the cylinder in the compression stroke. The result is that fuel is not burned fully, resulting in blue and white smoke and lower power outputs until the engine has warmed. This is especially the case with indirect injection engines, which are less thermally efficient. With electronic injection, the timing and length of the injection sequence can be altered to compensate for this. Older engines with mechanical injection can have mechanical and hydraulic governor control to alter the timing, and multi-phase electrically controlled glow plugs, that stay on for a period after start-up to ensure clean combustion; the plugs are automatically switched to a lower power to prevent their burning out. Wärtsilä states that there are two ways of forming smoke, on large diesel engines, one being fuel hitting metal and not having time to burn off. The other being, when too much fuel is in the combustion chamber. Wärtsilä have tested an engine and compared smoke-output, when using conventional fuel system and common rail fuel system, the result shows improvement on all operation conditions when using the common rail system.

Ecological effects

Experiments in 2013 showed that diesel exhaust impaired

bees Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfam ...

' ability to detect the scent of

oilseed rape Rapeseed (''Brassica napus ''subsp.'' napus''), also known as rape, or oilseed rape, is a bright-yellow flowering member of the family Brassicaceae (mustard or cabbage family), cultivated mainly for its oil-rich seed, which naturally contains ...

flowers.

Remedies

General

With

emission standard Emission standards are the legal requirements governing air pollutants released into the atmosphere. Emission standards set quantitative limits on the permissible amount of specific air pollutants that may be released from specific sources over ...

s tightening,

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-ca ...

s are having to become more efficient and have fewer pollutants in their

exhaust Exhaust, exhaustive, or exhaustion may refer to: Law * Exhaustion of intellectual property rights, limits to intellectual property rights in patent and copyright law ** Exhaustion doctrine, in patent law ** Exhaustion doctrine under U.S. law, i ...

. For instance, light duty truck must now have

NOx In atmospheric chemistry, is shorthand for nitric oxide () and nitrogen dioxide (), the nitrogen oxides that are most relevant for air pollution. These gases contribute to the formation of smog and acid rain, as well as affecting tropos ...

emissions less than 0.07 g/mile, and in the U.S., by 2010, NOx emissions must be less than 0.03 g/mile. Moreover, in recent years the United States, Europe, and Japan have extended emissions control regulations from covering on-road vehicles to include farm vehicles and locomotives, marine vessels, and stationary generator applications. Changing to a different fuel (i.e.

dimethyl ether Dimethyl ether (DME; also known as methoxymethane) is the organic compound with the formula CH3OCH3, (sometimes ambiguously simplified to C2H6O as it is an isomer of ethanol). The simplest ether, it is a colorless gas that is a useful precurs ...

, and other bioethers as

diethyl ether Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liq ...

) tends to be a very effective means to reduce pollutants such as NOx and CO. When running on dimethyl ether (DME) for instance, particulate matter emissions are near-nonexistent, and the use of diesel particulate filters could even be omitted. Also, given that DME can be made from animal, food, and agricultural waste, it can even be carbon-neutral (unlike regular diesel). Mixing in bioether (or other fuels such as hydrogen) into conventional diesel also tends to have a beneficial effect on the pollutants that are emitted. In addition to changing the fuel, US engineers have also come up with two other principles and distinct systems to all on-market products that meet the U.S. 2010 emissions criteria,

selective non-catalytic reduction Selective non-catalytic reduction (SNCR) is a method to lessen nitrogen oxide emissions in conventional power plants that burn biomass, waste and coal. The process involves injecting either ammonia or urea into the firebox of the boiler at a locati ...

(SNCR), and

exhaust gas recirculation In internal combustion engines, exhaust gas recirculation (EGR) is a nitrogen oxide () emissions reduction technique used in petrol/gasoline, diesel engines and some hydrogen engines. EGR works by recirculating a portion of an engine's exhaust ...

(EGR). Both are in the exhaust system of diesel engines, and are further designed to promote efficiency.

Selective catalytic reduction

Selective catalytic reduction Selective catalytic reduction (SCR) is a means of converting nitrogen oxides, also referred to as with the aid of a catalyst into diatomic nitrogen (), and water (). A reductant, typically anhydrous ammonia (), aqueous ammonia (), or a urea ...

(SCR) injects a reductant such as ammonia or urea — the latter aqueous, where it is known as diesel exhaust fluid, DEF) — into the exhaust of a diesel engine to convert nitrogen oxides (NO_x) into gaseous

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seve ...

and water. SNCR systems have been prototyped that reduce 90% of the NO_x in the exhaust system, with commercialized systems being somewhat lower. SCR systems do not necessarily need particulate matter (PM) filters; when SNCR and PM filters are combined, some engines have been shown to be 3-5% more fuel efficient. A disadvantage of the SCR system, in addition to added upfront development cost (which can be offset by compliance and improved performance), is the need to refill the reductant, the periodicity of which varies with the miles driven, load factors, and the hours used. The SNCR system is not as efficient at higher revolutions per minute ( rpm). SCR is being optimized to have higher efficiency with broader temperatures, to be more durable, and to meet other commercial needs.

Exhaust gas recirculation

Exhaust gas recirculation (EGR), on diesel engines, can be used to achieve a richer fuel to air mixture and a lower peak combustion temperature. Both effects reduce NO_x emissions, but can negatively impact efficiency and the production of soot particles. The richer mix is achieved by displacing some of the intake air, but is still lean compared to petrol engines, which approach the

stoichiometric Stoichiometry refers to the relationship between the quantities of reactants and products before, during, and following chemical reactions. Stoichiometry is founded on the law of conservation of mass where the total mass of the reactants equ ...

ideal. The lower peak temperature is achieved by a

heat exchanger A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct conta ...

that removes heat before re-entering the engine, and works due to the exhaust gases' higher

specific heat capacity In thermodynamics, the specific heat capacity (symbol ) of a substance is the heat capacity of a sample of the substance divided by the mass of the sample, also sometimes referred to as massic heat capacity. Informally, it is the amount of heat t ...

than air. With the greater soot production, EGR is often combined with a particulate matter (PM) filter in the exhaust.Bennett, Sean (2004). Medium/Heavy Duty Truck Engines, Fuel & Computerized Management Systems 2nd Edition, . In turbocharged engines, EGR needs a controlled pressure differential across the exhaust manifold and intake manifold, which can be met by such engineering as use of a variable geometry turbocharger, which has inlet guide vanes on the turbine to build exhaust backpressure in the exhaust manifold directing exhaust gas to the intake manifold. It also requires additional external piping and valving, and so requires additional maintenance.

Combined systems

John Deere Deere & Company, doing business as John Deere (), is an American corporation that manufactures agricultural machinery, heavy equipment, forestry machinery, diesel engines, drivetrains (axles, transmissions, gearboxes) used in heavy equipment, a ...

, the farm equipment manufacturer, is implementing such a combined SCR-EGR design, in a 9-liter "inline 6" diesel engine that involves both system types, a PM filter and additional oxidation catalyst technologies. The combined system incorporates two

turbocharger In an internal combustion engine, a turbocharger (often called a turbo) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake gas, forcing more air into the engine in order to pr ...

s, the first on the exhaust manifold, with variable geometry and containing the EGR system; and a second a fixed geometry turbocharger. Recirculated exhaust gas and the compressed air from the turbochargers have separate coolers, and air merges before entering the intake manifold, and all subsystems are controlled by a central

engine control unit An engine control unit (ECU), also commonly called an engine control module (ECM), is a type of electronic control unit that controls a series of actuators on an internal combustion engine to ensure optimal engine performance. It does this by ...

that optimizes minimization of pollutants released in the exhaust gas.

Other remedies

A new technology being tested in 2016 has been created by

Air Ink AIR-INK is a proprietary brand of ink and composites products made by condensing carbon-based gaseous effluents generated by air pollution due to incomplete combustion of fossil fuels. Founded by Graviky Labs, a spin-off group of MIT Media Lab ...

which collects carbon particles using a "Kaalink" cylindrical device that is retrofitted into a vehicle's exhaust system, after processing to remove heavy metals and carcinogens, the company plans to use the carbon to make ink.

Water recovery

There has been research into ways that troops in deserts can recover drinkable water from their vehicles' exhaust gases.

References and notes

External links

Diesel Information Hub
, AECC

EnggStudy
Diesel Particulate Matter
a case study at ''www.defendingscience.org''
Clean School Bus USA
EPA Initiative
Weight of the Evidence or Wait for the Evidence? Protecting Underground Miners from Diesel Particulate Matter
Article by Celeste Monforton. ''American Journal of Public Health'', February 2006.
Diesel exhaust – peer-reviewed studies by Health Effects InstituteSafety and Health Topics: Diesel Exhaust
U.S. Department of Labor Occupational Safety & Health Administration

U.S. Department of Labor Occupational Safety & Health Administration
Diesel Exhaust Particulates: Reasonably Anticipated to Be A Human CarcinogenImpact of Fuel Metal Impurities on the Durability of a Light-Duty Diesel Aftertreatment System

National Renewable Energy Laboratory The National Renewable Energy Laboratory (NREL) in the US specializes in the research and development of renewable energy, energy efficiency, energy systems integration, and sustainable transportation. NREL is a federally funded research and ...

Acute Inflammatory Responses in the Airways and Peripheral Blood After Short-Term Exposure to Diesel Exhaust in Healthy Human Volunteers
American Journal of Respiratory and Critical Care Medicine
Diesel exhaust: what you need to knowHealth Effects of Diesel Exhaust
- fact sheet by Cal/EPA and

American Lung Association The American Lung Association is a voluntary health organization whose mission is to save lives by improving lung health and preventing lung disease through education, advocacy and research. History The organization was founded in 1904 to figh ...

{{Authority control Air pollution Air pollution control systems Diesel engines History of the diesel engine