Perpetual drought + constant wildfires.
I am not knowledgeable about the stats you provided but since the fires (over a year now) LA has been consistently red except for some rainy days, although it’s even been red during the rain. We can figure it out but we are leaving LA!
Little deceptive using the WHO interim targets there, those are way lower than the US EPA AQI standard. Show me Europe during the same time …
Out here on the US West Coast we have been under the influence of a strong inversion that has been trapping air near the surface for the last several days. In addition to stagnant air us up in the Pacific Northwest have had persistent fog. Get up above 1500’ and the weather is clear and warm!
I believe what might be happening in California the last few months is related to what was observed for the first time in history in 2025 — the unprecedented suppression of Panama’s Pacific upwelling in 2025. Here is the study:
https://www.pnas.org/doi/10.1073/pnas.2512056122#supplementary-materials
As the ocean warms I believe there is more water vapor coming from the ocean getting stuck over California as a high pressure system blocks particulates from leaving the area. We have a warmer ocean due to the increasing amount of energy trapped on the planet as greenhouse gases increase. This leads to more water vapor coming off the ocean and getting stuck as the high pressure system causes increasing Arctic amplification due to melting ice in the North Pole.
Further work from Francis and Vavrus that year suggested that amplified Arctic warming is observed as stronger in lower atmospheric areas because the expanding process of warmer air increases pressure levels which decreases poleward geopotential height gradients. As these gradients are the reason that cause west to east winds through the thermal wind relationship, declining speeds are usually found south of the areas with geopotential increases
– Quote from Wiki on Polar amplification