Smog Alert: Millions Urged Indoors This Weekend

Millions of residents across Southern California and Arizona are under air quality advisories due to expected unhealthy levels of ozone pollution, commonly known as smog. These alerts are in effect through Sunday evening.

Areas particularly affected include California's Imperial Valley, encompassing cities like El Centro and Calexico, and Arizona's Phoenix metro area and wider Maricopa County. The National Weather Service warns that heat and stagnant air conditions are trapping pollutants near the ground, leading to accumulations.

Ozone pollution forms when vehicle exhaust and industrial emissions react in sunlight and heat. Weather conditions, including warm temperatures and intense sun, exacerbate the issue. Exposure can cause respiratory problems, including shortness of breath and asthma attacks, with sensitive groups at higher risk.

Authorities are urging residents to limit outdoor activities, especially during peak pollution hours in the afternoon and early evening. They also encourage actions to reduce pollution, such as limiting vehicle use and avoiding gasoline-powered lawn equipment. Air quality alerts are becoming more frequent in the Southwest due to a combination of extreme heat and urban emissions.