Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Emergency

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2025. This website is no longer updated and links to external websites and some internal pages may not work. More information »

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Climate Change
    • Emergency Response
    • Environmental Information by Location
    • Environmental Justice
    • Greener Living
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History
    • Staff Directory

Nitrogen Dioxide (NO2) Pollution

  • Nitrogen Oxides

    Nitrogen Dioxide (NO2) is one of a group of gases called nitrogen oxides. 

    12/10/2024 - EPA completes review of secondary standards. 

Nitrogen Dioxide Basics

  • What is NO2 and how does it get in the air?
  • What are the harmful effects of NO2?
  • What is being done to reduce NO2 pollution?
Other Common Air Pollutants
  • Ground-level Ozone
  • Particulate Matter (PM)
  • Carbon Monoxide (CO)
  • Lead (Pb)
  • Sulfur Dioxide (SO2)

See information on all criteria air pollutants.

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?
Contact Us about Nitrogen Dioxide (NO2) Pollution to ask a question, provide feedback, or report a problem.
Last updated on January 16, 2025
  • Assistance
  • Ayuda
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • Aide
  • Asistans
  • Korean
  • Assistência
  • Russian
  • Tulong
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions

Follow.