Best air purifier?

I’m in the SF Bay Area of California and currently locked indoors because of the hazardous air quality from the fires (were in a red zone marked “unsafe for breathing”). My son is almost 3 weeks and I’m so concerned for his developing lungs! He already seems to be struggling to breathe and the smoke is getting more intense. Does anyone have a really good air purifier that they could recommend? I know it won’t solve the problem completely, but even if we could get a little bit of relief I would be grateful.