The National Ambient Air Quality Standards (NAAQS) are limits on the amount of pollutants that can be present in outdoor air without harming public health or the environment.

 The National Ambient Air Quality Standards (NAAQS) are limits on the amount of pollutants that can be present in outdoor air without harming public health or the environment. The U.S. Environmental Protection Agency (EPA) sets the standards and reviews them periodically to determine if changes are needed. 

Here are some key facts about NAAQS: 

Criteria pollutants

The Clean Air Act requires the EPA to set standards for six criteria pollutants: carbon monoxide, lead, nitrogen dioxide, ozone, particulate matter, and sulfur dioxide. 

Primary and secondary standards

There are two types of standards: primary standards protect public health, while secondary standards protect the environment. 

Review process

The EPA periodically reviews the science behind the standards to determine if changes are needed. For example, the ozone standard was lowered from 75 ppb to 70 ppb in 2015. 

Air Quality Index

The Air Quality Index is linked to the NAAQS, so the cutoff for the Code Orange threshold also changes when the standards are revised. 

India's NAAQS

India is developing new, stricter air quality standards because the current standards are 14 years old. IIT Kanpur was given the task of reviewing the NAAQS and sug

gesting changes.