Nitrogen Dioxide (NO2) Pollution

Nitrogen Dioxide (NO₂) is one of a group of gases called nitrogen oxides (NO_x). While all of these gases are harmful to human health and the environment, NO₂ is of greater concern.

April 2018: EPA takes final action to retain the NO2 standards. Learn more

Nitrogen Dioxide (NO2) Pollution

Nitrogen Dioxide Basics

What is NO₂and how does it get in the air?
What are the harmful effects of NO₂?
What is being done to reduce NO₂ pollution?

Setting and Reviewing
the Standards

What are NO₂ standards?
How are the standards developed and reviewed?
What scientific and technical information supports reviews?

Implementing the Standards

Designations: how do we know if an area is not meeting NO₂ standards?
What are the state implementation plan (SIP) requirements?
How do states develop SIPs and start attaining the standards?

Nitrogen Dioxide (NO2) Pollution

Nitrogen Dioxide (NO2) Pollution

Nitrogen Dioxide Basics

Other Common Air Pollutants

Setting and Reviewingthe Standards

Implementing the Standards

Setting and Reviewing
the Standards