I am curious about your opinions. California has many fires and air quality index is 58 in San Francisco today. New Delhi is often more than 100. Do you pay attention to the air quality and whether you should bicycle or not?
No. There is no alternative, I don't drive a car. When I'm out of supplies, time to shop! Low air quality is no longer my fault.
OTOH I don't have asthma. I do carry a 3m M95 mask if smoke gets too bad. Which I wear in stores, these days.
You would be shocked by what I spit up after shifts fighting chip fryer or bake oven fires. City fire department would come, but stand there and watch us maintenance men work. Shoveling out burning chips onto concrete floor & spraying water on them, mostly. Lungs & trachia are lined with cilia, and if you're not a smoker, they do their job pushing out bad particles.
Remember native Americans used to burn the prairies to keep down the weeds & tree saplings. Kansas ranchers still do. It's a tradition still be be adopted by California.
During a severe smoke season in 2018 I made the mistake of being stubborn and foolish and rode several times during heavy smoke (the AQI was over 200). It took a most of the following winter before I felt like I was breathing right.
In general it is an extremely Bad Idea to exercise in severely polluted air. I would think hard about doing anything outside if the AQI is higher than 100.
From the following map I see that several places in CA right now have unhealthy, very unhealthy, or hazardous air: