What is it?
A gas that forms when sunlight reacts with pollution from cars, power plants, and industrial sources. Different from the protective ozone layer high in the atmosphere; this is the ozone you breathe.
Why it matters
Short-term exposure triggers asthma attacks and reduces lung function. Long-term exposure is associated with increased respiratory mortality.
Reference value
EPA's standard is 70 ppb (parts per billion) over an 8-hour average. Above 70 is non-attainment.
Related health outcomes
- Asthma
- COPD
- Reduced lung function
Data source
EPA Air Quality System (AQS) · View source →