Carbon Monoxide (CO)
This pollutant is very common in urban settlements where there is a lot of combustion from autos and other equipment that use fossil fuels. CO is a colorless, odorless and can very deadly if inhaled, with symptoms of headaches, dizziness, nausea, breathlessness, collapse and loss of consciousness — as it works to reduce the amount of oxygen that is in the body, depriving the brain and other tissue of oxygen. CO is also an indoor pollutant and a CO detector can help to detect the presence of CO in your home.
Ozone comes in two types, Ground Level Ozone (bad ozone) and Stratospheric Ozone (good ozone). Bad ozone is a secondary air pollutant, which means it is a reaction of oxides of nitrogen and volatile organic compounds in the presence of sunlight. The chemicals in this reaction come from emissions from autos, industrial facilities, gasoline vapors and chemical solvents. The effects of breathing in bad ozone include chest pain, coughing, throat irritation and congestion. It can also trigger all sorts of lung-related conditions including bronchitis, emphysema, and asthma. It also has effects on ecosystems, plants and water life.
This pollutant has its source from smelters (metal refineries) and other metal industries. Lead particles can also be found in the combustion of leaded gasoline in piston engine aircraft; waste incinerators (waste burners), and battery manufacturing. The use of lead products in gasoline for vehicles has been reduced in recent time, as there are strong laws against its use. Lead usually ends up in the bone and can interfere badly with blood production. Lead is high in many slums where they are constantly burning metal, iron and aluminium waste.
Nitrogen Dioxide (NO2)
NO2 affects respiratory functions of animals and humans. It causes problems such as wheezing, coughing, colds, flu and bronchitis. About 1% of NO2 exists naturally, from soils and plants, and also by the action of lightning. The bulk of NO2 in the atmosphere is from the burning of fossil fuels, coal, oil and gas. Food processing, metals and other manufacturing industries also produce lots of NO2, which also reacts with other chemicals to form photochemical smog.
Particulate Matter (PM)
These include all the very tiny solid and liquid particles that find their way into the atmosphere. All pollutants that are not gaseous in nature qualify as particulate matter. They may be primary or secondary in nature. Examples include particles from industrial processes, farming (ploughing, field burning), and unpaved roads or during road constructions. They also include common things like pollens and other particles dispersed into the air by plants during spring and summer. Small particulate matter measures up to about 2.5 micrometres. Big particulate matter measures up to 10micrometers. PMs exposures worsen heart or lung diseases and cause respiratory problems. Long-term exposures can cause heart or lung disease and sometimes premature deaths.
Sulfur Dioxide (SO2)
SO2 is a colorless gas, with a smell that resembles burnt matches. SO2 comes mainly from smelters, utilities, petroleum and cement/concrete work. SO2 is detrimental to trees and green plants. It also reacts with moisture in the atmosphere to form acid rain. It causes acidification in water bodies, causing harm to life forms that depend on such water bodies. SO2 exposure causes respiratory and cardiovascular problems to humans too.