Particulates or aerosols Come from lots of natural and man-made sources Natural sources Salt from ocean spray Dust from fields Volcanic eruptions Forest fires It is worth noting that natural sources can often be far worse than man-made sources

Particulates or aerosols Man-made sources Fly ash from coal combustion Ash from petroleum, but it occurs at 1/20 coal ash Iron and steel mills Cement manufacturing Burning of wood and other materials Coal dust from mining of coal (Black Lung) Measured in terms of the number of micrograms of particulates per cubic meter Standard is no more than 50 ug/m3 for particles with sizes greater than 10 microns in a year, but this does not account for chemical composition of the particulates

Map of particulate matter levels

Natural Dust

Volcanic eruptions Eruptions put large amounts of sulphur dioxide, hydrochloric acid and ash into the stratosphere. Hydrochloric acid is rained out of the atmosphere Sulphur dioxide reacts with water and forms sulphuric acid. The sulfuric acid condenses, forming aerosols. On the surface of the aerosols, chemical reactions occur which increase levels of chlorine which reacts with nitrogen and causes destruction of ozone in the stratosphere. This aerosol layer also reflects sunlight, and can cool the atmosphere.

Fly Ash Residue of coal burning Contains silicon dioxide, calcium oxide, arsenic, beryllium, boron, cadmium, chromium, chromium VI, cobalt, lead, manganese, mercury, molybdenum, selenium, strontium, thallium, and vanadium, along with dioxins and PAH compounds

Fly Ash In the past, was released into the atmosphere. In the US, it is now it is captured and stored at the coal plants or in landfills 43% is recycled and used in cement, grout, roofing tiles, paints, metal casings, filler in wood and plastic products.

Storage problems Kingston TN, Dec 23, 2008. Containment failure at the TVA plant. Not classified as a hazardous waste by the EPA Some concern that the level of radioactivity in the fly ash is equal to or more than you receive living near a BWR nuclear facility.

Effects of particulate matter Size is critical Your body has mechanisms designed to filter out particles with sizes larger than 1 um. (nose, mucous membranes, sneezing and coughing. However, smaller particles can pass into the lungs and cause problems

Effects of particulate matter Respiratory problems Lung cancers Particles can carry other toxic substance Health begins to deteriorate for long term exposure at levels of 80 ug/m3 . Decrease in sunlight-cities with high levels of population and industry receive 20% less sunlight than areas with less population and industry. Buildings and clothing damaged Toxic substances in the particulates can contribute to decay of masonry and corrosion of metals

Removal of particulates Natural processes –particles stay in the atmosphere days to years Gravity Precipitation small particles for nuclei around which raindrops form Rain washes out particulates Natural processes cannot keep up with the rate of man made particulate pollution

Removal of particulates Removal of ash from coal burning 2 types of ash Bottom ash-heavy, sinks to the bottom of the boilers Fly ash –light goes up the stack and released in to the atmosphere Bag house- air passes through a set of vibrating filters. The vibrations shake the particles out of the filter and they sink to the bottom for collection

Removal of particulates Electrostatic precipitators Gas molecules are ionized in a high electric field. Ions stick to particulates, giving them a charge. They are attracted to the metal plates which are at a high electric potential and stick

Removal of particulates Cyclone separators Gas is circulated in a circular motion Particles hit the walls and settle out Not very efficient for small particles

Removal of particulates Scrubbers Gas is sprayed with water, and the spray collects the particulates and is fed out the bottom. The waste water needs further treatment to remove the particulates.

Black Lung Disease Also called coal workers' pneumoconiosis Coal dust particles are too small to be filtered by the bodies natural filtration systems Once in the body, it cannot be removed or destroyed In the lungs, it is engulfed by white blood cells known as macrophages and it stays in the lungs or lymph nodes Aggregations of these carbon filled macrophages form which cause inflammation, fibrosis and lesions Lung efficiency is reduced, leading to other complications such as respiratory or heart failure http://www.courier-journal.com/cjextra/blacklung/index.html -A Louisville Courier Journal article on the state of Black Lung Disease in KY Responsible for 1500 deaths in the US each year

Black Lung Disease