Unit 8: Pollution: module 4.42: Air pollution

Module 4.42 (module 42, 4th edition text)

Big ideas: 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"

What is a "criteria"? good/bad

6 major pollutants: “criteria pollutants”

Mnemonic: SOX/NOX, CO/O3, PM/Pb

Added in 2007: CO2, VOC, Hg

From your text:

Context and relevance:

SOx: Sulfur Dioxide (SO2) and other SOx versions

From 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)

NOx: Nitric oxide (NO2) and other NOx versions

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

CO: Carbon monoxide

Emission from car exhaust, or other incomplete combustion: C + O2 —> CO2
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 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.

Ozone

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?

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

PM: Particulate Matter

Look up 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 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.

Pb: Lead

In the old days, there was leaded gasoline, and highly leaded gasoline (called "super" or "ethyl" because they used tetraethyl lead 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
Decreases mental capacity (e.g. Roman insanity theory)
Coal smoke contains lead, along with Mercury and other heavy metals. Sludge from mining is worse.

VOC: Volatile Organic Compounds

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
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 (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.

Air Quality monitoring: Purple Air: note the PM 2.5 graphs

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