Particulate emissions are emissions characterized by the presence of small particles of solids and liquids. These common byproducts of combustion are a major health and environmental concern in many regions of the world, and steps have been taken to reduce particulate emissions and to educate people about their risks. These emissions are also known as particulate pollution or particulate matter, with the vast majority of such emissions coming from factories, and around 10% coming from vehicles on the road.
Sometimes, particulate emissions are visible in the form of soot or smoke, because the particles are so large. Most are not visible, however, which is part of what makes them dangerous, because people do not realize that the emissions are occurring. Small particles are also more dangerous because they are less likely to be trapped in the mucus linings of the nose and throat.
For animals, particulate emissions pose a threat to cardiovascular and lung health. In the lungs, particulates can block or rupture the aveoli, interfering with lung function. A number of respiratory conditions including asthma and cancer are linked to exposure to particulate emissions. The heart muscle and blood vessels can also be damaged by particulates if they enter the bloodstream through the lungs, causing widespread medical problems.
Plants can also be damaged by particulate emissions; the particulates may block their leaves so that they cannot photosynthesize properly. The climate as a whole can be heavily impacted by such emissions, as they can block the sunlight so that it cannot reach the Earth. Haze caused by particulates can interfere with visibility, react with other pollutants to produce dangerous forms of pollution, interfere with air quality to the point that people have difficulty breathing, cause a decrease in crop yields, and contribute to global warming trends.
The only way to address particulate emissions is to reduce the production of particulates and improve filtering so that when they are produced, they are less likely to be released. Many fuel efficiency standards which are designed to improve air quality address this, and factories and motor vehicles are required to use filtration systems for emissions to scrub particles from the air. While there is little to be done about the particulate matter which has already been released, people can take steps to minimize the production of additional materials, and avoid incidents like the infamous Great Smog of 1952 which killed thousands of people in London, England.