Enduring Understanding:

• Human activities have physical, chemical, and biological consequences for the atmosphere.

Learning Objective:

• Identify indoor air pollutants.

• Describe the effects of indoor air pollutants.

Essential Knowledge:

• Carbon monoxide is an indoor air pollutant that is classified as an asphyxiant.

• Indoor air pollutants that are classified as particulates include asbestos, dust, and smoke.

• Indoor air pollutants can come from natural sources, human-made sources, and combustion.

• Common natural source indoor air pollutants include radon, mold, and dust.

• Common human-made indoor air pollutants include insulation, Volatile Organic Compounds (VOCs) from furniture, paneling and carpets; formaldehyde from building materials, furniture, upholstery, and carpeting; and lead from paints.

• Common combustion air pollutants include carbon monoxide, nitrogen oxides, sulfur dioxide, particulates, and tobacco smoke.

• Radon-222 is a naturally occurring radioactive gas that is produced by the decay of uranium found in some rocks and soils.

• Radon gas can infiltrate homes as it moves up through the soil and enters homes via the basement or cracks in the walls or foundation. It is also dissolved in groundwater that enters homes through a well.

• Exposure to radon gas can lead to radon-induced lung cancer, which is the second leading cause of lung cancer in America.

Sources

• Indoor air pollution can come from natural sources, human-made sources, and combustion

• Mold, dust, and radon all come from natural sources

• Asbestos and combustion (most of the time) are human-made sources

Types

Mold

• Mold can be found in homes, schools, and buildings with poor ventilation

• When water leaks and/or there is too much humidity, mold can grow undetected

  • This may occur after flooding damage

• Mold can infect respiratory passageways

  • This results in eye, nose, and throat irritation

Dust

• Dust can contain particulates of different sizes

  • Particulates are minute separate particles

  • Particles are identified by their size in nanometers

  • The two main categories are PM10, coarse matter, and PM2.5, fine matter

• Home heating and cooling systems have filters that should be changed regularly

  • This keeps particulate matter and dust from cycling through the house and irritating the eyes, nose, and throat

Smoke

• Spoke produces particulates that irritate and damage respiratory systems

• Sources of smoke include candles, fireplaces, cookstoves (wood, charcoal, animal dung), unvented space heaters or kerosene heaters, cigarette smoke, and smoke from nearby wildfires

• Most are anthropogenic but wildfires can be natural

Radon

• Radon is a gas that results from decaying uranium, and it is odor- and color-less

• Some rocks and soils contain uranium, which decays into radon-222

  • As it does, the gas seeps into the atmosphere

• Some gas can get into houses or buildings built on these soils due to cracks in building foundations or basement walls and floors

• The Environmental Protection Agency estimates that 1 in 15 homes in the US will have elevated radon levels

• Water can also carry radon gas into homes and buildings

  • People who get their water from a well should test it at least once for radon

• Radon decays into radioactive particles, which are inhaled and then deposited in the lungs

  • The cells of lung tissue become irradiated, damaging the DNA

  • This is the second leading cause of lung cancer in America

• Radon tests can be performed to determine the risk

• Monitoring and remediation can reduce the risk of exposure

• Sealing cracks and venting easily reduced the risk

Asbestos

• Asbestos was originally used as insulation but has been found to cause lung cancer

• It is comprised of many small fibers; small enough to get into and clog the blood flow in the alveoli in the lungs

• Asbestos works well in the walls and isn’t very dangerous, but once the walls are opened or disturbed, it becomes a problem

Building and Furnishing

• There are a number of products we use/d to build and furnish buildings that have negative consequences

• For example, lead can be found in older paints and is very dangerous

• Volatile Organic Compounds (VOCs) can be found in furniture, paneling, carpets, cleaning supplies, fabric softener, and dryer sheets

• Formaldehyde can be found in building materials like treated woods, carpets, glues, and resins

• Insulation can contain asbestos in older homes and buildings

• Some have been found and are now regulated, but others we are still finding out about

Combustion

• Combustion releases a number of air pollutants such as nitrous oxides (NOx), sulfur dioxide (SO2), particulates, smoke, and carbon monoxide

• Carbon monoxide is produced when fuel is burned

  • Certain household items can produce these and other flames that can poison humans and animals

  • These household items include small engines, stoves, lanterns, grills, fireplaces, furnaces, and cars

• Carbon monoxide is considered an asphyxiant, impairing the ability to red blood cells to carry oxygen through the body

  • CO reacts with hemoglobin in red blood cells to create a molecule that can no longer carry oxygen

  • This can result in dizziness, nausea, and suffocation in small amounts

  • In larger amounts, it can kill you, and since CO is odorless and colorless, you wouldn’t know before you’re too weak and disoriented to do anything