Area Under Air Quality Alert Sunday as Fireworks Smoke Raises Health Risk

The National Weather Service has issued an air quality alert for Pasadena and the rest of the San Gabriel Valley, warning of harmful fine particle pollution from fireworks that is expected to last until 3 p.m. Sunday, July 5.

The alert, based on a South Coast Air Quality Management District (AQMD) advisory, covers most of Los Angeles County.

Particle pollution levels can vary by time and location depending on emissions and local weather conditions, meaning some areas of Pasadena and surrounding communities could see worse air quality than others during the alert period.

Fine particle pollution can get deep into the lungs and cause serious health problems, including heart attacks, bronchitis, asthma attacks and difficulty breathing, the alert states.

Health officials say everyone can be affected, but sensitive groups face greater risk. Those groups include people with lung or heart disease, older adults, people who are pregnant, children and anyone who spends significant time outdoors.

The AQMD outlined precautionary guidance based on the Air Quality Index (AQI), urging residents to check air quality levels and adjust their activity accordingly:

• Unhealthy for Sensitive Groups (orange): Sensitive groups should limit extended or intense outdoor activity.
• Unhealthy (red): Everyone may experience health impacts. Sensitive groups should avoid extended time outdoors.
• Very Unhealthy (purple): Sensitive groups should avoid all outdoor physical activity. Everyone else should avoid extended or intense outdoor activity.
• Hazardous (maroon): Everyone should avoid all outdoor physical activity.

To help keep indoor air clean while pollution levels are elevated, the alert recommends several precautions. Residents should keep windows and doors closed and run an air conditioner or air purifier where possible.

The alert specifically advises against using whole-house fans or swamp coolers that draw in outside air, since these systems can pull polluted air into homes rather than filtering it out. Additional sources of indoor and outdoor pollution — including fireplaces, candles, incense, grilling and gasoline-powered lawn and garden equipment — should also be avoided during the alert period, according to the NWS.

The advisory does not specify particular Pasadena neighborhoods or issue separate guidance for different parts of the city; the alert applies broadly across most of Los Angeles County, with the acknowledgment that conditions may shift depending on local weather and the timing and volume of fireworks activity in a given area.

Residents can monitor current and forecasted air quality conditions by visiting aqmd.gov/alertinfo, the source recommended in the alert.