South Coast AQMD Issues Ozone Advisory Due to Heat Wave

Valid Monday June 14, 2021 through Saturday June 19, 2021

This advisory is in effect through Saturday. South Coast AQMD will issue an update if additional information becomes available.

The National Weather Service has issued Excessive Heat Watches and Warnings for much of the South Coast Air Basin and the Coachella Valley, increasing the likelihood of poor air quality in many areas. This heat wave is expected to last through at least Saturday.

Levels of ground-level ozone (smog) – the predominant summertime pollutant – are likely to reach the Unhealthy or higher Air Quality Index (AQI) levels throughout most of the South Coast Air Basin and the Coachella Valley. Very Unhealthy AQI levels are expected in favored locations such as Southwestern San Bernardino County. Areas near the coast may reach Unhealthy for Sensitive Groups or higher AQI levels.

Atypically poor air quality is due to a strong high pressure ridge located over the Desert Southwest. The National Weather Service forecasts that temperatures will be highest Tuesday through Saturday, with temperatures 10-20 degrees F above average. Elevated temperatures, which enhance ozone formation rates and increase emissions of chemicals leading to ozone formation, coupled with predicted light winds may cause unusually high and persistent levels of ozone pollution.

Ozone air pollution can cause respiratory health problems, including trouble breathing, asthma attacks, and lung damage.  Research also indicates that ozone exposure can increase the risk of premature death.  Children, older adults, and people with asthma or COPD may be more sensitive to the health effects of ozone.

When air quality is Unhealthy and reaches an air quality index (AQI) range of 151 to 200, everyone may begin to experience some adverse health effects, and residents with higher sensitivity to air pollution may experience more serious effects.  People with heart disease, pregnant women, children and older adults, and people with lung disease, such as asthma should avoid prolonged time outdoors.

When air quality is Very Unhealthy with an AQI range of 201 to 300, everyone in the region may experience more serious health effects. People with heart disease, pregnant women, children and older adults, and people with lung disease, such as asthma should avoid all outdoor physical activity. Everyone else should avoid prolonged or heavy outdoor activity.

South Coast updates can be found at www.aqmd.gov/advisory.

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