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,

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

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.

The hazardous air quality in Los Angeles is largely a result of smoke from the Pacific Palisades Fire, intensified by strong Santa Ana winds.