According to the Environmental protection Agency, there are six major pollutants which can impact on human health and well-being.
Particulate matter: Particulate matter is the term for a mixture of solid particles and liquid droplets found in the air.
These particles come in many sizes and shapes and can be made up of hundreds of different chemicals.
Some are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires.
Fine particles (2.5 parts per million)are the main cause of reduced visibility (haze) in parts of the United States, including many of our treasured national parks and wilderness areas.
Carbon monoxide: Breathing air with a high concentration of CO reduces the amount of oxygen that can be transported in the blood stream to critical organs like the heart and brain.
At very high levels, which are possible indoors or in other enclosed environments, CO can cause dizziness, confusion, unconsciousness and death.
Nitrogen dioxide: Nitrogen dioxide primarily gets in the air from the burning of fuel. NO
It forms from emissions from cars, trucks and buses, power plants, and off-road equipment.
Breathing air with a high concentration of NO can irritate airways in the human respiratory system. Such exposures over short periods can aggravate respiratory diseases, particularly asthma, leading to respiratory symptoms (such as coughing, wheezing or difficulty breathing).
Sulfur dioxide: The largest source of Sulfur dioxide in the atmosphere is the burning of fossil fuels by power plants and other industrial facilities.
Short-term exposures to SO can harm the human respiratory system and make breathing difficult. Children, the elderly, and those who suffer from asthma are particularly sensitive to effects of SO.
Ground-level Ozone: The ozone layer in the lower area of the lower portion of the stratosphere, approximately 12 to 19 miles above the surface of the planet (20 to 30 km).
Although ozone protects us against UV radiation, when it is found at ground level it can cause health problems for vulnerable people who suffer from lung diseases such as asthma.
It is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) – that are found in exhaust fumes – in the presence of sunlight.
Lead: Major sources of lead in the air are ore and metals processing and piston-engine aircraft operating on leaded aviation fuel.
Other sources are waste incinerators, utilities, and lead-acid battery manufacturers. The highest air concentrations of lead are usually found near lead smelters.
Depending on the level of exposure, lead can adversely affect the nervous system, kidney function, immune system, reproductive and developmental systems and the cardiovascular system.
Infants and young children are especially sensitive to even low levels of lead, which may contribute to behavioural problems, learning deficits and lowered IQ.
Source: EPA