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 This website is no longer updated and links to external websites and some internal pages may not work.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

Sulfur Dioxide (SO2) Pollution

  • Sulfur Oxides

    Sulfur Dioxide (SO2) is one of a group of gases called sulfur oxides . The other gases in the group are much less common in the atmosphere .

    12.10.2024 - EPA completes review of secondary standards. 

Sulfur Dioxide Basics

  • What is SO2 and how does it get in the air?
  • What are the harmful effects of SO2?
  • What is being done to reduce SO2 pollution?

Other Common Air Pollutants

  • Ground-level Ozone Pollution
  • Particulate Matter (PM)
  • Carbon Monoxide (CO)
  • Lead (Pb)
  • Nitrogen Dioxide (NO2)

See information on all criteria pollutants .

Setting and Reviewing the Standards

  • What are sulfur dioxide standards?
  • How are they developed and reviewed?
  • What scientific and technical information supports reviews?

Implementing the Standards

  • Designations: how do we know if an area is not meeting SO2 standards?
  • What are the state implementation plan (SIP) requirements?
  • How do states develop SIPs and start attaining the standards?
Contact Us about Sulfur Dioxide (SO2) Pollution to ask a question, provide feedback, or report a problem.
Last updated on December 11, 2024
  • 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.