What are the most common compounds found in fire residues (e.g. PAHs, soot, VOCs)?

The most frequent compounds we find after a fire are PAHs, soot particles, and VOCs.

PAHs are toxic organic chemicals created when carbon-based materials burn without enough oxygen. Some are known carcinogens, so even trace levels matter.
Soot is mainly carbon but can carry absorbed metals and tars, which irritate the lungs and eyes.
VOCs, or volatile organic compounds, include formaldehyde, benzene, and toluene — chemicals that easily vaporise and cause lingering odours and respiratory irritation.

Together, these compounds can create poor indoor air quality long after visible damage is cleaned. That’s why post-fire air and surface testing are essential before returning a space to use.