APES Chapter 15 Atmospheric Pollution and Stratospheric Ozone Depletion

Modules 46-50

Air Pollution

The introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, or to alter ecosystems.

Usually occurs in the troposphere (16k up); aka ground pollution.

Criteria Air Pollutants

Six polutants with limits put on them under the clean air act. They are: sulfur dioxidem nitrogen oxides, carbon monoxide, particulate matter, tropospheric ozone, and lead.

Carbon dioxide was not included, but added later. VOCs are still not a part of it, but still widely known and considered.

S.N.C.P.T.L super nasty crap pollutes the land

Sulfur Dioxide

SO₂

A corrosive gas that comes primarily from combustion of fuels such as coal and oil, as well as natural volcanic eruptions.

It is a respiratory irritant and can also hurt plant tissue.

Nitrogen Oxides

NO_x NO₂ is a pungent, reddish-brown gas, and NO is a colorless, odorless gas, NO₂ turns into NO.

Come from any combustion in the atmosphere, usually motor vehicles and fossil fuel combustion. Natural forest fires and lightning also contribute.

Helps to form ozone.

Carbon Oxides

CO and CO₂

Carbon Monoxide (CO) is a colorless, odorless gas that is formed during incomplete combustion, a common pollutant of vehicle exhaust. Very dangerous as an indoor pollutant, especially with poor ventilation.

Carbon Dioxide (CO₂) is a colorless, odorless gas formed during complete combustion of most matter.

Particulate Matter

PM or particulates/ particles

Solid or liquid particles suspended in air. It comes from combustion of wood, animal manure, and other biofuels, coal, oil, and gasoline.

Sizes range from .01 micrometers to 100 micrometers. Anything larger than10 is usually filtered out. Particles of PM_2.5 are of greater concern because they are harder to filter out.

Cause haze (reduced visibility)

Photochemical Oxidants

Oxides are reactive compounds that remove electrons from other substances. Photochemical Oxidants are formed as a result of sunlight reacting with chemical oxides.

There are many kinds but Ozone (O₃) is a big focus.

Smog

A mixture of oxidants and particulate matter, coming from the words smoke and fog.

Photochemical Smog: called Los Angeles-type smog or brown smog. Dominated by oxidants like ozone.

Sulfurous Smog: called London-type smog, gray smog, or industrial smog. Dominated by sulfur dioxide and sulfate compounds.

Lead and Mercury

Pb and Hg

Lead is a trace material that occurs naturally in rocks and soils, present in small concentrations in fuels including oil and coal. Was added to vehicle fuels for years.

Mercury is toxic to the nervous system. Often gained in humans through seafood.

Volatile Organic Compounds

VOCs

Hydrocarbons (compounds that contain hydrogen-carbon bonds) like gasoline, lighter fluid, perfumes, oil paints, etc. VOCs can also be naturally given off by trees in a non-harmful form.

Primary vs Secondary Pollutants

Primary: A polluting compounds that comes directly out of a smokestack, exhaust pipe, or natural emission source. Includes CO, CO₂, SO₂, NO_x, and most particulate matter.

Secondary: a primary pollutant that has undergone transformation in the presence of sunlight, water, oxygen, or other compounds. Includes ozone, (NOx and VOCs), SO_3, and more.

Ozone should non exceed .075 parts of ozone per million for more than 4 days in the US

yeah

The “Black Triangle”

Hugely polluted areas in Germany, Poland, and the Czech Republic.

Thermal Inversion

A situation in which a relatively warm layer of air at mid-altitude covers a layer of cold, dense air below, opposite of what it should be.

Inversion Layer: the layer of warm air that traps emissions in a thermal inversion.

Methods to Control Sulfur and Nitrogen Oxide Emissions

• Fluidized bed combustion: granulated coal is burned close to granulated calcium carbonate, which absorbs sulfur and releases calcium sulfate, a less harmful and actually useful counterpart.

• Controlling oxygen levels and heat carefully

• Catalytic converters in cars

Methods to Control Particulate Matter

• Gravitational settling, where particles settle at the bottom and can be disposed of.

• Fabric filters/ baghouse filters allow gas to pass but not PM. Some can remove 100% of PM.

• Electrostatic precipators remove PM using electrical charges, causing particles to coalesce.

• Scrubbers use water and air to seperate and remove particles. Remaining sludge needs to be disposed of. Can also remove sulfur dioxide

How does Stratospheric Ozone Breakdown?

When chlorine is introduced into the atmosphere, it bonds with oxygen, forming ClO, and then returns to chlorine again when that oxygen bonds with another oxygen. Chlorine acts as a catalyst, as it speeds up the reaction but is not used up. One chlorine molecule can breakdown 100,00 ozone molecules before the process is stopped.

Indoor Air Pollutants

• Carbon Monoxide: mostly comes from natural heating sources. It bonds with hemoglobin easier than oxygen, leading to oxygen deprivation and death.

• Asbestos: Thin fiber good for insulation. Becomes an issue when fine fibers become airborn.

• Radon 222: a radioactive gas that occurs naturally from the breakdown of uranium. Attatches to dust and is inhaled.

• VOCs n products: often found in furniture, household products like glue, and building materials. One of the most toxic is formaldehyde, which emits gas over time, and can burn eyes and hurt lungs over long periods.

C.A.R.V

Sick Building Syndrome

A buildup of toxic pollutants in an airtight space, as seen in newer buildings.

Has four causes: inadequate or faulty ventilation (traps pollutants inside), chemical contamination from indoor sources (i.e. glues), chemical contamination from outside sources (i.e. exhaust fumes), or biological contamination (i.e. mold).

What percent of deaths are caused by indoor air pollution in developing countries?

90%

Off-gassing

Gasses given off by materials, often VOCs, like formaldehyde.