[ksab]

There is no "safe" threshold for particulate matter (PM) exposure. Our nose, mouth and throat are very inefficient at filtering particles less than 2.5 microns. As a consequence, a large proportion of these particles simply enter the respiratory tract (tracheobronchial and alveolar regions) relatively unimpeded.

Assessing indoor exposure to PM is challenging because it is highly dependent on location, the physical properties of the home, and human behaviour. Consequently, it can be difficult to clearly identify/quantify health benefits.

Even though you live in a reasonably clean city, you can still further reduce your exposure to indoor PM by changing your behaviour, filtering your air and using existing equipment in your home properly.

1) In non-smoking homes, the biggest indoor source of PM is cooking (especially frying and broiling). You can reduce your exposure by a) keeping your range hood in good working order (change filters), b) using the range hood every time your cook, c) opening a window while cooking and d)stepping away from the stove whenever possible.

2) There are multiple other sources products that can produce shocking amounts of PM through direct emission and secondary reactions involving ozone. I would describe these exposures as completely unnecessary and can be eliminated by simply not using the products in the first place: a) candles, b) incense, and c)air fresheners and cleaning products with lemon & pine scents.