Temperature inversion and air pollutants

Temperature inversion refers to a situation where the normal temperature profile of the atmosphere is inverted or reversed. In a typical atmosphere, the temperature usually decreases with increasing altitude. However, during a temperature inversion, warm air is trapped above cooler air, resulting in a layer of warm air sitting on top of a layer of cooler air.

Impact of temperature inversion on air pollutants

During a temperature inversion, the movement of air near the surface becomes restricted. This has significant implications for air pollutants, as they tend to behave differently in these conditions. The following points explain the impact of temperature inversion on air pollutants:

1. Accumulation above the inversion layer: Air pollutants, being heavier than the surrounding air, tend to accumulate above the inversion layer. This is because the inversion layer acts as a lid, preventing the vertical mixing of air. As a result, pollutants emitted near the surface are trapped below the inversion layer, leading to their accumulation.

2. Accumulation below the inversion layer: While pollutants tend to accumulate above the inversion layer, there can also be instances where certain pollutants accumulate below the inversion layer. This can happen when the pollutants are lighter than the surrounding air or when they undergo chemical reactions that alter their properties. Under these circumstances, pollutants can get trapped below the inversion layer and accumulate in the lower atmosphere.

3. Lateral dispersion: Although the vertical movement of air is limited during a temperature inversion, pollutants can still disperse laterally. This means that pollutants can spread horizontally within the layer of trapped air. However, their horizontal movement is also restricted to a certain extent due to the stable atmospheric conditions created by the inversion.

Conclusion

In summary, during a temperature inversion, air pollutants tend to accumulate both above and below the inversion layer. The inversion layer acts as a barrier, preventing the vertical mixing of air and leading to the accumulation of pollutants. However, lateral dispersion is still possible within the trapped air mass. Therefore, the correct answer is option 'D' - all of the above.