Southern California was full of smoke on Saturday as wildfires continued to wreck havoc with little containment.

The August Complex Fire, which on Thursday became the California's largest ever, has merged to cover 875,059 acres (about 3,541 square km), with only 25 percent contained, the California Department of Forestry and Fire Protection (Cal Fire) said on Saturday.

In the San Bernardino Mountains, the 14,212 acre (57.5 square kilometers) El Dorado Fire which occurred on Sept. 5 was contained by 41 percent Saturday noon, according to Cal Fire.

A smoke advisory remains in effect Saturday in most of Los Angeles County and parts of Orange, Riverside and San Bernardino counties due to the Bobcat Fire burning in the Angeles National Forest which had scorched 29,245 acres (118.4 square kilometers) with only 6 percent containment.

The White House announced Saturday that U.S. President Donald Trump will visit California on Monday for a briefing with emergency response officials on the devastating wildfires racing through the region, according to local media.

Air quality affected

A map updated by the South Coast Air Quality Management District (SCAQMD) showed air quality in the region during this weekend is expected to range from moderate to unhealthy for sensitive groups, such as children, elderly, and people with respiratory or heart disease.

In some areas near the wildfire scenes, the air quality is forecast as "unhealthy" level.

"Breathing in smoke can aggravate lung disease, cause asthma attacks, cause acute bronchitis, and increase the risk of respiratory infections," the National Weather Service warned on its official website.

The SCAQMD issued a smoke advisory every day since the El Dorado and Bobcat fires erupted last weekend and brought ash, dust and debris across the region. Additionally, smoke from wildfires in Northern and Central California is making its way south.

Meanwhile, evacuation warnings remained in the cities of Duarte, Bradbury, Monrovia, Arcadia, Sierra Madre, Pasadena and Altadena, which stand along the foothill of Santa Ana Mountain where the Angeles National Forest is located.

These cities have hundreds of thousands of residents, with a high percentage being Chinese Americans.