Once inhaled they penetrate deep into the lung and deposit there more easily than larger particles. There is also some evidence that long-term exposure to particles may be linked with cancer. Particulate matter is often contaminated with other pollutants such as ozone, sulfur dioxide or carbon monoxide. US EPA concluded that premature deaths can result from both chronic and acute exposure to particulate matter. Smoke from various sources in the community is a major source of particulate matter.
Wood burning produces fine particulate matter and is very dangerous.
They occur naturally and are all potent carcinogens. Toxic compounds such as PAH's and carbon monoxide are produced as a result of incomplete combustion of fuel. Carbon monoxide reduces the oxygen carrying capacity of the blood. VOC's including benzene, aldehydes, phenols and organic acids emanate from wood smoke. High concentrations of hydrocarbon odours are obnoxious to some people and can cause eye and lung irritation.