Toxic substances list: ozone

Ground-level ozone is a colourless gas found in the lower atmosphere. Virtually none of the ground-level ozone measured in air is directly emitted from biogenic (natural) or anthropogenic (human) sources. Ozone is the product of a complex series of chemical reactions primarily involving sunlight and two precursor pollutants: nitrogen oxides (NOx) and volatile organic compounds (VOCs). These precursor gases are emitted from combustion processes often associated with industry and the transportation sector, and from various commercial and industrial processes and solvent use. Some NOx and VOCs may be produced by biogenic sources, especially in summer when VOC emissions from vegetation (agricultural crops and forests) are greatest. Ozone and the precursor gases can be transported over long distances. This phenomenon is often found in the north-eastern United States and in eastern Canada where large weather patterns are not impeded by major geographical features.

CAS (Chemical Abstract Service) registry number: 10028-15-6

Risk assessment

• National Ambient Air Quality Objectives For Ground Level Ozone
• Order Adding Toxic Substances to Schedule 1 to the Canadian Environmental Protection Act, 1999
• CEPA 1999 Schedule 1 - List of Toxic Substances - This substance has been added to the List of Toxic Substances. It is entering or may enter the environment in a quantity or concentration or under conditions that:
  a) have or may have an immediate or long-term harmful effect on the environment or its biological diversity.
  c) constitute or may constitute a danger in Canada to human life or health.
• Full life cycle management of the substance (Track 2) under the Toxic Substances Management Policy

Sources

This substance is entering the environment from the following sources:

• Electric Power Generation Sector (Fossil Fuel)
• Vehicles, Engines and Fuels

Risk management strategy

Click on the following link to view strategies and actions recommended to manage risks associated with the substance:

• Interim Plan 2001 on Particulate Matter and Ozone

Risk management tools

Tools developed to manage risks associated with the substance:

• New Source Emission Guidelines for Thermal Electricity Generation
• Canada-wide Standards for Particulate Matter (PM) and Ozone
• On-Road Vehicle and Engine Emission Regulations
• Off-Road Small Spark-Ignition Engine Emission Regulations
• Off-Road Compression-Ignition Engine Emission Regulations
• Environmental Code of Practice for Integrated Steel Mills
• Environmental Code of Practice for Non-Integrated Steel Mills

Consultation

Consultation (past and present) on the substance:

• Federal Agenda on Cleaner Vehicles, Engines and Fuels
• Preliminary Consultation on a Discussion Draft of the Off-Road Compression-Ignition Engine Emission Regulations (archived consultation document)
• Federal Agenda for the Reduction of VOCs from Consumer and Commercial Products

Other information

• Clean Air in Canada: 2003 Progress Report on Particulate Matter and Ozone
• Volatile Organic Compounds in Consumer and Commercial Products
• Air pollution

Contact

Substances Management Information Line
Chemicals Management Plan
Environment and Climate Change Canada
Gatineau, QC K1A 0H3

Telephone: 1-800-567-1999  (in Canada) or 819-938-3232
E-mail: substances@ec.gc.ca

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