Pollution Can be Reduced with the Help of Simulation

Pollution Can be Reduced with the Help of Simulation - SimScale

Photography by Kim Daniel

Every year, across the globe, air pollution causes 2.5 million premature deaths. Most of these deaths occur in Asia and India, but no region of the world is spared. Two primary pollutants are responsible for these deaths: 1) ozone, and 2) fine particulate matter.


Roughly 500,000 deaths are caused by ozone (O3). Ozone as discussed here is called “low level ozone” and is to be distinguished from the higher level ozone layer. Low level ozone is formed when hydrocarbons and nitrogen oxides which have been emitted from vehicles, power plants, and industrial plants, react with sunlight. The reaction with sunlight can occur directly at the source of the emissions or many kilometers down wind.

Ozone has a very sharp and distinctive odor similar to chlorine bleach. Exposure to very low concentrations of ozone (.1 to 1 μmol/mol) produces headaches, burning eyes and irritation to the respiratory passages. Even low concentrations of ozone in air are very destructive to organic materials such as latex, plastics and animal lung tissue.

Particulate Matter

Roughly 2,000,000 deaths are caused by particulate matter. Particulate matter is a mixture of extremely small solid particles and liquid droplets and is made up of a number of components, including acids (such as nitrates and sulfates), organic chemicals, metals, and soil or dust particles.

The size of particles is directly linked to their potential for causing health problems. Particles that are 10 micrometers in diameter or less are of special concern because they are able to pass through the throat and nose and enter the lungs. Once inhaled, these particles can affect the heart and lungs and cause serious health effects.

In 2013, a study involving 300,000 people in nine European countries revealed that there was no safe level of particulate matter concentration. For each 10 μg/m3 increase in concentration of 10 micrometer diameter particles, the lung cancer rate rose 22%. The smaller 2.5 micrometer particles were even more deadly. Each 10 μg/m3 increase in concentration caused a 36% increase in lung cancer because they can penetrate deeper into the lungs.

Concentration Levels and Dispersion

For both ozone and particulate matter, the higher the concentration, the more dangerous to humans; therefore, to reduce the harmful effects, concentration must be decreased. Decreasing concentration can be accomplished in many ways: one of these is dispersion.

Dispersion is affected by many factors including wind direction, wind speed, type of terrain and heating effects. These effects can be described as either stable or unstable, where stability is determined by wind (which stirs the air) and heating effects (which cause convection currents).

In unstable conditions (moving air and convection currents), ground level concentrations will decrease around sources. For elevated emissions such as those released from a chimney, concentration levels will increase.

In stable conditions (stagnant air and convection currents), ground level concentrations will increase around sources. For elevated emissions, once again, such those released from a chimney, the concentration levels will decrease.

How Engineering Simulation can Help Study and Reduce Pollution

Engineers and scientists can use simulation software to study pollution dispersion and concentration levels. Simulation software like SimScale, allows to set air movement and convection currents as the background conditions. Then a pollution source can be added on top of these conditions. The dispersion and concentration of pollution around the source can then be visualized.

For example, air movement and convection currents around a chimney can be set according to differing degrees of stability, and then pollution dispersion and concentration levels can then be observed at different positions relative to the chimney. Using the same stability assumptions, the design of the chimney can be changed, and the resulting dispersion and concentration levels re-observed until an optimum configuration is discovered.

Using this approach can aid in the construction of more effective structures (such as chimneys) to better disperse and reduce pollution concentration, thereby, benefiting the health of all of us.

See this project and find out how SimScale can help you create more effective structures to reduce pollution.

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