Question

Most hazardous metal pollutant of automobile exhaust is
a. Mercury
b. Lead
c. Cadmium
d. Copper

Answer 1

Hint: Hazardous metal pollutant is also used as an anti knocking agent by combining with organic compounds. It is used for blocking radiation and also used in batteries. It is also used for the soldering of metals but is highly hazardous to human health.

Complete answer
The most hazardous metal pollutant of the automobile industry is lead. Lead might enter inside the human body and lead accumulation can lead to several diseases. Lead poisoning can occur which can cause damage to our internal organs. It can retard the mental and physical growth of children. It can cause great damage to the nervous system of children.

Additional Information:
Several other pollutants are also released by automobiles and for the reduction of the automobile, pollution steps have been taken by the government.
One of the major steps that were taken by the government of Indian was compulsory PUC certification of petrol-driven vehicles which tests for CO and hydrocarbons. The new fuel policy given by the government was mentioned under Euro II norms. The following instruction and guideline were given:
- The maximum sulphur content in diesel should not exceed 350 ppm.
- The maximum sulphur content in petrol should be limited to 150 ppm.
- The aromatic hydrocarbon content of fuel should be limited to 42% of the fuel used and not more than that.
The Euro II norms applied to only 11 cities initially but from April 2005 these norms were to be followed throughout the country. Several norms that were established are given below:

- From April 2005 the eleven cities that were earlier following Euro II norms were shifted under Euro III norms. The eleven cities were Delhi, Agra, Kanpur, Ahmedabad, Surat, Mumbai, Pune, Hyderabad, Bangalore, Chennai, and Kolkata.
- From April 2010 Euro IV norms were made compulsory in those eleven cities and Euro III was applicable for the rest of the country.
- In 2017 Euro IV norms were established nationwide.
- The use of unleaded petrol was made compulsory so that motor vehicles equipped with catalytic converters can function optimally. The lead inside petrol can deactivate the catalyst.

So, the correct answer is,” Most hazardous metal pollutant of automobile exhaust is lead.”

Note:
Even though lead is the most hazardous, other metals and non-metals can also be poisonous and cause several diseases like:
- Minamata Disease: Caused by mercury accumulation within the body.
- Black-Foot Disease: Is caused due to arsenic
- Itai-Itai disease: Can occur due to cadmium poisoning.
- Fluorosis or Knock Knee disease