The Health of our Air Document in PDF Format Please direct all questions and comments to Barry Grace Aerosols Aerosols are solid particles in atmosphere, either formed in the air by reactions among gases or injected into the air by processes on the ground. The main sources of aerosols are natural events like volcanoes, sea spray, forest fires, and soil erosion. But some aerosols are also produced by human activity, like combustion of fossil fuel. Particles smaller than 2.5 mm are a serious concern for both visibility and human health.
Aerosols absorb and reflect light, producing the haze in cities.
They can also be breathed in and stay in the respiratory system causing respiratory illness and even cancer. Aerosols also have an important effect on global climate. They also reflect solar radiation, thereby cooling the earth. The amount of aerosols produced by Canadian agriculture has not been measured routinely but is probably small. The most common aerosol from Canadian farms is probably dust from soil erosion.