Where do HC and CO in car exhaust come from?

Mech4cars.com – Where do HC and CO in car exhaust come from? – Cars with internal combustion engines do present a challenge for car makers. Engines must be able to minimize the toxic compounds that come from their exhaust gases. This is most important is the problem of passing emissions testing which is a strict regulation even in developing countries.

Where do HC and CO in car exhaust come from?

In the process, the emission test does not take a long time, one that is tested is the content of hydrocarbons or HC and carbon monoxide or CO. It is interesting to ask, where do HC and HO come from?


HC and CO in car exhaust

The HC and CO content comes from the combustion process in the combustion chamber. The combustion of fuel and air in the combustion chamber will result in an oxidation process or reaction. If this process does not take place completely, the CO and HC content will appear.

The imperfection of this process can be from the insufficient amount of oxygen carried by air entering the combustion chamber. But a small spark plug flame can also be another consequence. A bad spark plug condition results in misfiring and increases the HC compound as a result.

There is something else besides a lack of oxygen and a lack of good work that causes the (high) content of HC and CO in the exhaust gas, namely engine oil. Under certain conditions, for example, due to engine age, components such as valve seals and piston rings will experience wear. From these two parts, oil can enter the combustion chamber. The oil will also burn and result in even more incomplete combustion.

From this condition, the carbon scale will form in the combustion chamber in addition to the increase in HC and CO.

If we look at the problem of high HC and CO, the tips for passing the emission test seem important for us to look carefully. We can also overcome the full carbon combustion chamber with engine load and are part of the exhaust emission pass test tips.

Definition of Emissions

The increasing number of motorized vehicles has a major influence on increasing air pollution. The remaining exhaust gas of motorized vehicles that comes out through the exhaust plays a major role in air pollution. There are many harmful substances in the exhaust gas or vehicle emissions to health, especially emissions from incomplete combustion.

The definition of emission or exhaust gas is the result of burning fossil fuels such as oil, natural gas, or coal which is wasted into the air. The things that affect are the composition, type, and size of the boiler and the fuel used.

Emissions play a major role in air pollution today and have a huge impact on health and also the environment both in the short and long term. However, to determine this, further studies must be carried out. The aim is none other than to take precautionary measures regarding the impact and how far it spreads.

Definition of Vehicle Gas Emissions

To be more specific on motorized vehicles, vehicle gas emissions are the residue of combustion in the internal combustion engine. The rest of this combustion will come out through the exhaust system or muffler.

Obviously, this is very dangerous because this emission contains quite a lot of harmful substances, including:

  1. CO (Carbon Monoxide), this gas has no color or odor. However, this gas is very toxic if it is inhaled by humans. The most fatal consequences will result fainting to death.
  2. CO2 (Carbon Dioxide), this gas has a very dangerous impact because it is very influential on global warming.
  3. NOX (Nitrogen Oxide), this gas can cause respiratory tract disorders and is very painful in the eyes.
  4. HC (Hydrocarbon), this gas comes from incomplete combustion in a car engine, so in this gas, there are still remnants of unburned gasoline vapor and exits through the exhaust.

To anticipate the harmful effects of vehicle emissions, synergy is needed between Brand Holder Agents (APM) and the government. It is very important to take steps and actions to reduce exhaust emissions from motorized vehicles.

Steps that have been taken by the government at this time are improving the quality of fuel and tightening emission test standards. Meanwhile, Brand Owners’ Agents increase EURO 2 standards so that the cars produced can meet emission test standards.

The second step will not work properly if there is no awareness from car owners to reduce exhaust emissions. To do this, there are several things that we must do as car owners, including:

  1. Carry out emission tests of cars within a certain period of time.
  2. Perform periodic servicing on a regular basis.
  3. Immediately check if the exhaust gas from the muffler smells and smokes unnaturally.
  4. Use fuel that has been recommended by APM.
  5. Just 2-3 minutes to warm up the car engine.

Automobile Emission Hazards – HC and CO in car exhaust

From the explanation above, we can know that emissions are very dangerous for health and the environment because they contain various hazardous substances. We are never aware that exposure to these hazardous substances enters the blood circulation and respiratory system so that they can cause long-term damage to the body.

HC and CO in car exhaust

The following are the dangers of car emissions on health:


Even though currently fuel has a much lower level of pollution, it is still dangerous because the number of vehicles is increasing from year to year. Even in small amounts, exposure to these carcinogenic substances can cause organ damage and trigger cancer.

There are two hazardous chemicals that have carcinogenic properties in vehicle exhaust, namely:

  • Benzene is an aromatic compound in basic fuel mixtures. This compound comes out together with vehicle exhaust gas and it is very easy to enter the body when inhaled or when it comes into contact with the skin. High levels of benzene in the blood will interfere with the formation of red blood cells.
  • Lead is a metal compound that comes from vehicle exhaust. Lead is very dangerous because it can settle on the surface of any object. These accumulated deposits can enter the body when there is interaction with the skin. High levels of lead can increase the risk of anemia and result in impaired brain performance.

Causes of Respiratory System Damage

The first part of the body that can be dangerously affected by exhaust emissions is the respiratory system, the dangerous effects that lurk are as follows

Oxygen levels in the body will decrease, and red blood cells will more easily bind CO (Carbon Monoxide) content in vehicle exhaust than O2 (Oxygen), thus reducing oxygen levels in the blood in the body. This is very dangerous because it can cause long-term brain damage and cause shortness of breath.

Damage to the respiratory tract, vehicle dust particles including lead that comes out of the exhaust gas can cause long-term damage to the respiratory tract such as asthma and lung cancer.

Damage to the Circulatory System

High exposure to CO (Carbon Monoxide) in the blood will increase blood viscosity and inflammatory protein levels, which will result in the development of atherosclerosis. This situation will get worse with exposure to sulfates which can trigger damage to blood vessels. Even more dangerous is the content of polycyclic aromatic hydrocarbons (PAHs) which can cause heart attacks and a high risk of death.

Car Emission Test

One of the anticipatory steps that we can take to overcome the problem of vehicle exhaust emissions is to conduct an emission test. An emission test is an action to measure the exhaust gas of motorized vehicles in order to monitor the performance of the car engine.

By carrying out an emission test, you will be able to find out how much the level of harmful substances is from the vehicle exhaust gas so that health and the environment can be better maintained. What we can get from this emission test is how effective the combustion process in car engines is by analyzing the levels of carbon dioxide and hydrocarbons contained in the exhaust gases. By carrying out this emission test, car owners can also adjust the fuel and air mixture even better.

The following are important benefits of a vehicle emission test:

  1. Able to know with certainty how effective the combustion process is through analysis of CO2 and HC content
  2. Able to adjust the fuel and air mixture properly
  3. Know with certainty the condition of the vehicle engine
  4. Ensures fuel effectiveness while maximizing power
  5. The environment is much better with cleaner air
  6. Able to find out the damage to the car engine more quickly.

Hazardous Substances Contained in Exhaust Emissions – Including HC and CO in car exhaust

The following is a discussion regarding the hazardous substances contained in exhaust emissions. Anything? This is who we mean!

Carbon monoxide

This substance has neither color nor smell but is a very dangerous substance. This gas can make a person faint to death if inhaled in large quantities.

carbon dioxide

This one gas is actually a gas that we will release when we do the breathing process. However, if this gas is produced by vehicles in large quantities, it can increase global warming. There are also rare trees that can convert this substance into oxygen.

Nitric oxide

This gas can cause a person’s eyes to sting and also interfere with the respiratory system. If you inhale too much of this one substance, you can feel short of breath.


Hydrocarbons are usually found from incomplete combustion in a vehicle. We can find this gas in the unburned gasoline chamber and will later come out through the exhaust.

1 thought on “Where do HC and CO in car exhaust come from?

  1. Pingback: Why Does Water Come Out Of The Exhaust When The Car Engine Is Running? | Hi-tech for Future

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