Gaseous Air Pollutants

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Toxic air pollutants are gaseous pollutants that are carcinogenic and can cause serious health issues.

There are many different toxic air pollutants but we will be focusing on

  1. Carbon monoxide
  2. Sulfur dioxide
  3. Lead
  4. Ozone
  5. Nitrogen dioxide

CARBON MONOXIDE

Chemical formula: CO
Molar Mass: 28.010 g/mol
Appearance : Colourless 
Odour: Odourless

Carbon Monoxide, CO, is a covalent compound made up of a carbon and an oxygen atom connected with a triple bond. 

It is a common air pollutant produced in motor vehicles and anything that burns hydrocarbon fuels like natural gas and petrol. In vehicles, when carbon reacts with insufficient supply of air (oxygen) it will undergo incomplete combustion hence forming carbon monoxide instead of carbon dioxide.

Image result for incomplete combustion reaction

A common tale about Carbon monoxide poisoning is about a person falling asleep inside a car, only to lose consciousness and pass away due to the carbon monoxide poisoning.

Carbon monoxide is an odourless and colourless gas, making it all the more lethal since it cannot be easily detected. CO kills by replacing oxygen within the bloodstream, quickly become fatal within minutes. Early symptoms of CO poisoning includes headache, dizziness and nausea. Even at low concentrations, CO can still cause fatigue in healthy people.


SULFUR DIOXIDE

Chemical formula: SO2
Molar Mass: 64.066 g/mol
Appearance : Colourless 
Odour: Pungent

 

Sulfur Dioxide, SO2, is a covalent compound consist of a sulfur atom and 2 oxygen atoms covalently bonded via double bond.

It is another toxic gas that is produced by the burning of fossil fuels by industrial facilities. It is also a part of a group of harmful gases known as Sulfur Oxides and SO2 is of greater concern among the gases in this group.

Sulfur Dioxide causes breathing difficulties in humans, particularly for young children, elderly and asthmatics. High concentrations of SO2 also leads to the formation of other Sulfur Oxides, hence creating additional air pollution. Apart from health problems to humans, SO2 also harms the environment by damaging plants and contributing to acid rain. Apart from that, SO2 reacts with other substances to become small particles that can lead to haze.

Image result for sulfur dioxide form acid rain equation

Formation of SO2 leads to further reaction and formation of sulfuric acid, H2SO4


LEAD

Related image

 

Chemical formula: Pb
Molar Mass: 207.2 g/mol
Appearance : dull grey (upon exposure to air)

Lead, Pb, is a natural heavy element found within the Earth’s core and is largely released into the air due to metal and ore processing activities. Silver-Lead ore processing will release the production of lead into our environment.

Image result for metal and ore processing forms lead

Lead, once ingested into the body, accumulates within human bones. The accumulated lead causes problems to the nervous system, kidneys, immune system, reproductive systems and developmental system. Young children are particularly susceptible to lead and it can affect their growth, development and intelligence. Lead pollution also causes a decreased growth in plants.


OZONE

Image result for ozone molecule

Chemical formula: O3
Molar Mass: 48.000 g/mol
Appearance : Colourless to pale blue gas
Odour: Pungent

Ozone, O3, is a covalent bond composed of 3 oxygen atoms. From what we are familiar with, ozone is formed when O2 reacts with the ultraviolet light in the strastosphere (one of the Earth’s atmosphere layer).

However, in this context of gaseous air pollutant, ozone as an air pollutant is referred to as ground level ozone which is formed when oxides of Nitrogen (NOx) reacts with volatile organic compounds (VOC) in the presence of sunlight. Sources of these emissions are based from industrial facilities, vehicle exhausts, electric utilities and many more.

Image result for ground level ozone chemical equation

Ozone in air will cause heath effects especially for people with lung diseases like asthma. Apart from affecting humans and animals, it has a direct effect on sensitive vegetation and ecosystems.


NITROGEN DIOXIDE

Chemical formula: NO2
Molar Mass: 46.005 g/mol
Appearance : Reddish-brown gas
Odour: pungent

Nitrogen Dioxide, NO2, is a covalent compound consist of a nitrogen atom and 2 oxygen atoms covalently bonded. It is formed from combustion of Nitrogen monoxide (NO) in air.

Like Sulfur Dioxide, Nitrogen Dioxide is also a part of a group of toxic gases known as Nitrogen Oxides and is of greater concern among the group. Nitrogen Dioxide is mainly emitted by the burning of fuel.

Nitrogen Dioxide affects humans’ respiratory system as well as reacting with other substance to form particulate matter and ozone which also causes other health problems. It is also a contributor to acid rain and haze.

Image result for nitrogen dioxide burning fuel


Image References:

http://www.labmuffin.com/labmuffin/wp-content/uploads/2013/12/incomplete-combustion.jpg 

http://www.gravitatechnomech.com/images/Lead-atoms.jpg

http://www.worstpolluted.org/files/FileUpload/pics/2011/WWPP_top%2010_mining-lead_615wide.jpg

https://upload.wikimedia.org/wikipedia/commons/3/33/Nitrogen-dioxide-3D-balls.png

http://media.whatsyourimpact.org/graphs/natural-sources-of-nitrous-oxide-emissions.png

Content References:

https://www.epa.gov/NO2-pollution

http://www.greenfacts.org/en/nitrogen-dioxide-no2/

https://www.epa.gov/ozone-pollution/ozone-basics#effects

https://www.tceq.texas.gov/airquality/sip/criteria-pollutants/sip-lead

https://www.epa.gov/lead-air-pollution/basic-information-about-lead-air-pollution

http://www.environment.gov.au/protection/chemicals-management/lead

https://www.epa.gov/so2-pollution/sulfur-dioxide-basics

http://www.webmd.com/first-aid/tc/carbon-monoxide-poisoning-topic-overview

https://www.cdc.gov/co/faqs.htmhttps://www.epa.gov/indoor-air-quality-iaq/carbon-monoxides-impact-indoor-air-quality