Calculating air pollution from wildfires and other events has become more complicated. That doesn’t mean it’s necessarily more accurate.

Air quality in wildfire-stricken Los Angeles improved on Thursday from hazardous peaks hit earlier this month, as tiny soot particles that can penetrate the lungs and brain dropped to moderate levels,

Wildfire ash carries many carcinogens that could cause short- and long-term health problems, including asthma attacks and difficulty breathing.

The fresh air came after days of acrid smoke from wildfires, but officials warned that conditions could rapidly worsen again.

On Friday, the South Coast Air Quality Management District issued a smoke advisory for the fourth consecutive day, largely due to the elevated levels of unhealthy pollution billowing from the Eaton Fire in Altadena.

Wind gusts and dry conditions will linger throughout the day on Thursday in Los Angeles where firefighters hope to gain on their momentum against two major wildfires that have ravaged everything in their path.

Los Angeles is now a week removed from the day that multiple devastating wildfires erupted to torch tens of thousands of acres. But still, the question remains if people should wear masks to limit their exposure to toxins in the air.