Smog

The increase in the levels of SO₂, SO₃, NO_x, and suspended particulate matter creates havoc with the surrounding atmosphere. Out of these, SO₂ is the most potent as it causes bronchitis spasms. O₃ causes inflammations of the inner lining of air passages. A cocktail of these lethal substances narrows and inflames the air passages leads to smelling in the lining of the throat and finally wheezing and difficulty in breathing.

Figure 11.26 Effect of load on NOx emission for four-stroke normally and turbo-charged engines

2 Control of Emission from Diesel Engine

The main pollutants from the diesel engine as mentioned earlier are HC, CO, NO_x smoke, odour, and SO₂. The methods of reducing HC, CO, and NO_x from petrol engine are already discussed in detail and the same methods are also used for reducing the pollutants from a diesel engine. Therefore, the methods used to reduce smoke and odour which are additional pollutants from diesel engine are discussed here.