The EPA's AQI quantifies air pollution, sets out ranges of pollution, and associates health risks with each range. Quoting from PurpleAir: "101-150: Members of sensitive groups may experience health effects if they are exposed for 24 hours. The general public is not likely to be affected."
This is just the description of one single AQI range, but all the descriptions from all the sources I've been able to find for all the ranges detail health effects on 24-hour timescales.
Living in California, every year for the past several years has seen serious wildfires and dramatic corresponding drops in air quality. It seems reasonable to avoid going outside without an N95 mask when the AQI is 201+. However, assume that such wildfires continue every single year for the rest of my lifetime. What cumulative effects, if any, would such periodic exposure to air pollution have? For example: an AQI of 101-150 seems innocuous enough, but does it become something to worry about if one is exposed to it several months out of the year, every year?
Secondary, but related question: if there are any dangers of cumulative effects, do those dangers increase in smaller creatures? For example, do small children or pets face more significant dangers than human adults?