Air Quality Standards and Legislation Questions and Answers

Answer: A

It is expressed as a concentration averaged over a stated period and applies to the general atmosphere rather than to any single source. Emission standards, control efficiencies and stack heights are all means of achieving it rather than the standard itself.

Answer: B

It is derived from the exposure at which health effects appear, with a margin of safety for children, older people and those with respiratory disease. Secondary standards address welfare effects such as damage to materials, crops and visibility.

Answer: C

It limits what a chimney, vent or tailpipe may release, usually as a concentration or a mass per unit of production. It is enforceable against an identifiable operator, which is why regulators use it as the working instrument.

Answer: D

The Water Act of 1974 came first and created the pollution control boards, the Air Act of 1981 extended their remit to the atmosphere, and the Environment (Protection) Act of 1986 provided the umbrella legislation after Bhopal.

Answer: A

The Environment (Protection) Act was passed in 1986, in the aftermath of the Bhopal disaster, as umbrella legislation giving the central government wide powers to set standards and issue directions. The other dates belong to separate statutes: the Air Act is 1981 and the Water Act 1974, both of which predate it and are narrower in scope. Most current emission and ambient standards, including the National Ambient Air Quality Standards, are notified as rules under the 1986 Act rather than under those earlier laws.

Answer: B

The board examines the proposed site, process and control equipment before construction begins, so that unacceptable projects are stopped early. Consent to operate is a separate approval sought once the plant is built and the controls are in place.

Answer: C

Correct answer: An area notified by a state board where the Act's controls apply

Under the Air Act a state board, with the state government's approval, declares an area to be an air pollution control area, and the Act's operative provisions - consent requirements, emission standards, restrictions on fuels and appliances - then apply within it.

Notification is therefore the trigger that turns a general statute into an enforceable regime in a particular place. It does not prohibit industry, and it has nothing to do with monitoring station coverage or factory boundaries.

Answer: D

Correct answer: Central Pollution Control Board

The Central Pollution Control Board lays down the national ambient air quality standards, which apply uniformly across the country.

The division of labour is deliberate: the CPCB sets standards and co-ordinates, the state boards implement them - granting consents, monitoring and enforcing locally. The Bureau of Indian Standards writes product standards and the National Green Tribunal adjudicates disputes; neither sets ambient limits.

Answer: A

A short peak and a long low exposure can carry very different risks, so a pollutant often carries both an annual and a twenty-four hour value. Comparing a one-hour reading against an annual standard is the classic misuse of the numbers.

Answer: B

Correct answer: One number covering several pollutants

The index computes a sub-index for each monitored pollutant against its own breakpoint scale, and reports one figure so that air quality can be communicated without the public interpreting several concentrations in different units.

It is a communication device rather than a measurement: the reported value is the worst sub-index, and the prominent pollutant is named alongside it. It is neither a sum nor a ratio of emission to concentration, both of which would obscure what it exists to convey.