# Unit 8: Pollution: module 4.42: Air pollution

## <span style="font-weight: bold;">Module 4.42 (module 42, 4th edition text)</span>

<span style="font-weight: bold;">Big ideas: </span>air is shared by everyone on the planet, crosses international borders without consent, impacts innocents with little power.

Contrast this with solid, toxic or radioactive waste: usually disposed of on your own land, or with rivers, which demonstrate "continuity downstream"

<span style="font-weight: bold;">What is a "criteria"? good/bad</span>

<span style="font-weight: bold;">6 major pollutants: “criteria pollutants”</span>

- Sulfur dioxide: SO2 (could also be SOx)
- Nitrogen oxides: NOx (could be NO, NO2, or NO3)
- Carbon monoxide: CO
- Particulate matter: PM (PM 2.5, PM 5, PM10)
- Ozone: O3
- Lead: Pb

<span style="font-weight: bold;">Mnemonic:</span> SOX/NOX, CO/O3, PM/Pb

<span style="font-weight: bold;">Added in 2007: CO2, VOC, Hg</span>

<span style="font-weight: bold;">From your text:</span>

<div class="sandbox" id="bkmrk--6"><div id="bkmrk--7"><div id="bkmrk--8"><div><div class="container"><div class="frontside"><div class="iframe">![](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/p4XnKENw6xGTtEmX-screen-shot-2023-02-26-at-4-48-53-pm-sbnsmvjp.png)</div></div></div></div></div></div></div><div class="sandbox" id="bkmrk--12"><div id="bkmrk--13"><div id="bkmrk--14"><div><div class="container"><div class="frontside"><div class="iframe">![](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/e1Fj2JziGTuurcGf-criteria-pollutants-sources-mupsmy00.png)</div></div></div></div></div></div></div><span style="font-weight: bold;">Context and relevance:</span>

<span style="font-weight: bold;">SOx: Sulfur Dioxide (SO2) and other SOx versions</span>

- From [Methionine](https://en.wikipedia.org/wiki/Methionine) (amino acid in living things) in fossil fuels (look up the structure of this)
- Combines with water in the air to make H2SO4 (sulfuric acid, acid rain)
- When you breathe it, it burns your lungs, stings your eyes
- May look like "yellow smog"
- One example is VOG: sulfur dioxide and ash (volcanic glass)

<span style="font-weight: bold;">NOx: Nitric oxide (NO2) and other NOx versions</span>

- Various forms of oxidized nitrogen, which alone is inert and makes up 78% of the atmosphere at sea level
- From high temperature combustion (e.g. auto engines, esp. high efficiency ones, which burn at higher temps)
- Also from decomposition of fertilizers (e.g. Ammonium Nitrate)
- Combines with water to make HNO3 (nitric acid) which also burns your lungs and eyes

<span style="font-weight: bold;">CO: Carbon monoxide</span>

- Emission from car exhaust, or other incomplete combustion:  <span style="font-weight: bold;">C + O2 —&gt; CO2</span>
- Many people die camping by burning stoves in their tent without enough oxygen, forming carbon monoxide
- If not enough O2, then CO forms, like in a closed space (tent, hut, cold house in Texas)
- Toxic, permanently attaches to your [hemoglobin](https://en.wikipedia.org/wiki/Hemoglobin) rendering it useless for respiration. (30 day life cycle for your hemoglobin)
- Imagine the town van, but nobody gets off. The bus still goes, but nobody goes to town.
- For 30 days (until your red blood cells are replaced) no seats on the bus, no oxygen.

<span style="font-weight: bold;">Ozone</span>

- Ozone is formed by sunlight, splitting O2 into O which then joins another O2 to make O3
- Ozone in stratosphere is good, in troposphere bad
- Ozone (O3) blocks UV radiation, while Oxygen (O2) does not
- Stratospheric ozone is necessary to filter UV radiation. CFC (chloro-fluro-carbons) destroy this layer
- This caused an ozone hole over Antarctica: Why there?
- 

<div class="sandbox" id="bkmrk--25"><div id="bkmrk--26"><div id="bkmrk--27"><div><div class="container"><div class="frontside"><div class="iframe">![](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/XN1GSGfLEqXhrgHd-cfcs-ozone-hole-7lyjumvf.png)</div></div></div></div></div></div></div><div class="sandbox" id="bkmrk--28"><div id="bkmrk--29"><div id="bkmrk--30"><div><div class="container"><div class="frontside"><div class="iframe">![](https://bookstack.kamuela.org/uploads/images/gallery/2026-09/cJ2Sm4HUxWaZb1UC-montreal-protocol-xaig6bol.png)</div></div></div></div></div></div></div>

- How did we solve this? The 1987 Montreal Protocol:
- Tropospheric ozone causes lung and eye irritation, and is toxic to some organisms
- You may have heard of ozone generators used in hotel rooms to absorb smoke
- 

<span style="font-weight: bold;">PM: Particulate Matter</span>

- Look up [alveolus](https://en.wikipedia.org/wiki/Pulmonary_alveolus) in your lungs
- Particulate Matter (PM) is basically soot (carbon)
- PM2.5 is 2.5 microns in size, PM10 is 10 microns in size (there is also PM5)
- PM2.5 is most dangerous, smaller particles lodge deep in the lungs, beyond ability of [pulmonary cilia](https://en.wikipedia.org/wiki/Mucociliary_clearance) to flush out
- PM5, PM10 larger particles, get caught by cilia
- Main cause: coal fired power plants, diesel engines, oil fired power plants (carbon soot)
- See also vog: PM2.5 particles of ash (glass shards) with SO2 dissolved in water droplets (sulfuric acid): physical abrasive + corrosive acid = respiratory damage
- Fun fact: smokers get colds more often because tar in tobacco gums up the cilia, so they can't brush away germs and viruses.

<span style="font-weight: bold;">Pb: Lead</span>

- In the old days, there was leaded gasoline, and highly leaded gasoline (called "super" or "ethyl" because they used [tetraethyl lead](https://en.wikipedia.org/wiki/Tetraethyllead) as an additive to improve power)
- Gasoline additive (tetraethyl lead improves octane rating cheaply), replaced by other worse carcinogenic (cancer causing) chemicals like MTBE: [https://en.wikipedia.org/wiki/Methyl\_tert-butyl\_ether](https://en.wikipedia.org/wiki/Methyl_tert-butyl_ether)
- Decreases mental capacity (e.g. Roman insanity theory)
- Coal smoke contains lead, along with Mercury and other heavy metals. Sludge from mining is worse.

<span style="font-weight: bold;">VOC: Volatile Organic Compounds</span>

- Volatile organic compounds, e.g. gasoline vapors (why your gas cap must be on or you get a dashboard warning): [https://en.wikipedia.org/wiki/Volatile\_organic\_compound](https://en.wikipedia.org/wiki/Volatile_organic_compound)
- Aerosol vaporizers are also VOC generators (indoor air pollution)
- Remember water striders sitting on water, due to surface tension?
- Your alveoli are surrounded by water (blood) so they need a [surfactant](https://en.wikipedia.org/wiki/Pulmonary_surfactant) (detergent) to break the surface tension so they can expand you can breathe.
- If you breathe in VOC's (siphoning gasoline, vaping, or in the case of premature babies), the surfactant is gone, and you cannot breathe.
- Vaping is a concentrated version of VOCs, dissolving the surfactant in your lungs, causing "chemical pneumonia", only seen before in anesthesia and people siphoning gasoline or premature babies.

<div id="bkmrk-air-quality-monitori"><span style="font-weight: bold;">Air Quality monitoring:</span> Purple Air: note the PM 2.5 graphs

[https://www.purpleair.com/map?&amp;zoom=12&amp;lat=20.03156357084113&amp;lng=-155.69287088607177&amp;clustersize=30&amp;inc=313230\|313232&amp;orderby=L&amp;latr=0.28062097322957413&amp;lngr=0.3714752197265625](https://www.purpleair.com/map?&zoom=12&lat=20.03156357084113&lng=-155.69287088607177&clustersize=30&inc=313230|313232&orderby=L&latr=0.28062097322957413&lngr=0.3714752197265625)

Check out other locations...

<span style="font-weight: bold;">Vog forecast: </span>[http://weather.hawaii.edu/vmap/new/](http://weather.hawaii.edu/vmap/new/)

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