Question

Permissible levek of emission of various gases

Answer 1

The permissible levels of emission of various gases refers to the standards and regulations set for the amount of pollutant gases allowed out of a given engine or automobile in a given period of time. These standards vary from country to country and even in the same country, there might exist different standards for various regions. The standards also vary in terms of the type of engine and fuel used. (these regulations apply for both vehicles and industries)

Here is an example using the Bharat stage emission standard with references made  to the Euro 6 standards:

For trucks and buses: CO= 4.0,HC=0.55, NOx = 3.5, PM= 0.03

Light duty petrol vehicles ( 4 wheels): CO=2.27, HC=0.16, NOx= 0.11

3-2 wheel vehicles: CO= 1-1.25,HC+NOx= 1-1.25

Note: These standards vary from region to region and also in regards to the type of engine used.