Regional Ground-level Ozone Strategy

Ground-level ozone is a health harming contaminant that affects the air we breathe

Unlike the protective ozone layer in the atmosphere, ground-level ozone – the main part of smog – forms near the surface where people live and spend time outdoors. It is created when nitrogen oxides (NO_x) and volatile organic compounds (VOC) react in sunlight. Ground-level ozone can affect human health, our ecosystems, and agricultural crops.

The Regional Ground-Level Ozone Strategy was developed jointly by Metro Vancouver, the Fraser Valley Regional District, the Ministry of Environment and Parks, Environment and Climate Change Canada, and the Vancouver Fraser Port Authority. The Strategy summarizes the scientific understanding of ground-level ozone formation in the region and outlines policy directions to reduce ground-level ozone exposure.

Why managing ozone matters in our region

Ground-level ozone can irritate the respiratory system, worsen asthma symptoms, and reduce lung function. This can lead to increased school absences, doctor and emergency room visits, and hospital admissions. Ground-level ozone also affects the health of our ecosystems by slowing plant growth, increasing plants’ risk of disease, and reducing crop yields. Managing ozone levels helps protect both public health and the environment.

How ozone forms in our region

Ground-level ozone forms when NO_x and VOC emissions from vehicles, industry, and everyday products react in sunlight. Ozone levels tend to rise on hot, sunny days in our region.

Policy directions in the Regional Ground-Level Ozone Strategy

Understanding how ozone forms helps to guide effective actions to reduce exposure. The strategy outlines coordinated actions to reduce ozone formation and exposure in our region. The approach focuses on both short term conditions during the hottest summer days and year round emissions management.

Key policy directions

Maintain existing ozone warning programs during high ozone days.
Reduce NO_x emissions during peak summer periods in areas where they contribute most to ozone formation.
Reduce VOC emissions throughout the year, with a focus on the most reactive VOCs and on areas where VOC reductions are most effective.

Ongoing research and monitoring

Metro Vancouver and its partners continue to monitor ozone levels in the region and take action to protect air quality.

Ongoing work includes:

Monitoring long term ozone trends.
Studying how climate change may affect ozone formation and the frequency of hot, stagnant conditions.
Tracking emissions of NO_x and VOC across the region.
Investigating the use of modelling to assess how emissions in different parts of the region influence ozone levels across the airshed.