The 1930's apartment I live in could be best described as "drafty", with a noticeable amount of warm and cool air (including the dust it brings in) fluctuating throughout the days and seasons. This means occasionally the combination of humidity and heat can make even our often cleaned bedroom smell a little ripe...
Japanese white charcoal, also known as binchō-tan or binchō-zumi, is a traditional Japanese charcoal originating from the Edo period, made from ubame oak (Quercus phillyraeoides) through a carbonizing process using moderately low temperature, then blasting the wood at the end to a blistering 1000 °C into a super hardened (yet very light) state. The blackened shiny-sheen wood pieces are then mixed with a concoction of sand, earth, and ash onto it; the light coating of dust is where the name "white charcoal" originates.
Binchotan is already commonly marketed as water purification medium, but the kiln hardened charcoal is also very effective at absorbing humidity and odors from ambient air, especially in small spaces. My mother came upon a cache of binchō-tan in Koreatown for a reasonable price here in Los Angeles and gave me a few pieces to call my own.
I placed a small stack inside a wire basket, situating the collection near our bed, where the charcoal has done a noticeable job of reducing the humidity levels and absorbing any light odors. The room smells neutral and unscented, much better than any product masking smells with perfume. Every 2-3 weeks, I take the pieces outside to "recharge" in the sunlight for a few hours, and the pieces are ready to work their magic again.
(Images: Gregory Han; Rikumo)