indoor air pollution

• indoor air pollution: pollution found inside buildings and cars

  • can cause disease, headaches, coughing, nausea, burning eyes, chronic fatigue

  • can result in absenteeism, reduced productivity, cost of healthcare

• source of indoor pollutants

  • our focus will be on radon, formaldehyde, carbon monoxide, and asbestos

• radon: a radioactive gas that comes from the ground through cracks in the foundation

  • causes lung cancers

• formaldehyde: a volatile organic compound (VOC) found in plywood, particle board, paneling, drapes, upholstery, dry-cleaned clothing

  • worse in new buildings

• asbestos: a heat-resistant mineral that does not burn or conduct electricity

  • used for insulation

  • not harmful unless exposed or crumbling

  • causes lung cancer and mesothelioma

  • april 2022: EPA proposed ban of ongoing use of asbestos

• carbon monoxide (CO): the product of incomplete combustion of wood, gas, coal, natural gas, and kerosene; has no smell

  • reduces the ability of blood to carry oxygen

• indoor pollution in schools

  • investing in quality would help with COVID, flu and colds, asthma and allergies, student attention (poorer when hot)

• action items

  • test for radon

  • don’t buy furniture/appliances with formaldehyde

  • remove shoes when entering home

  • avoid houses build pre-1980 (may contain lead, asbestos)

  • don’t store solvents, gasoline, other VOCs in house

  • don’t smoke inside

  • install and check carbon monoxide detectors

acid deposition

the pH scale

• pH: a measure of how acidic or basic a solution is

• pH7: the neutral pH level of pure water

  • <7 — acidic

  • 7 — basic (or alkaline)

acid deposition

• the normal pH of rainfall is slightly acidic (pH 5-6) because as rain falls, it dissolves CO2 and creates carbonic acid

• acid deposition = acid rain + acid snow + acid particles

• affects buildings, forests (plants, soil), aquatic life, human health (asthma, bronchitis)

solutions to indoor air pollution

aesthetic degradation

• aka aesthetic pollution

• aesthetic degradation: undesirable changes in physical or chemical characteristics of the atmosphere

  • eg. noise, odors, light pollution

• don’t kill, but decrease quality of life

the Clean Air Act (1963, amended 1990)

• regulates emissions from stationary and mobile sources

• sets primary standards to protect health and secondary standards to protect crops, climate, visibility, etc.

• EPA establishes and monitors natural ambient air quality standards (NAAQS)

• constantly being litigated

technical solutions

• since the 1990’s, we’ve been burning cleaner gasoline

  • lead was phased out

  • sulfur content was reduced

  • cars have catalytic converters, which reduce pollutants in exhausted gases

  • emission standards for cars have been established

• other innovations — electrostatic precipitators in ducts, scrubbers in chimneys

marketing pollution rights

• an industrial plant that emits less than its limits receives pollution credits

  • such credits may be

    • used in another facility

    • banked for further expansion

    • sold to other utility or environmental groups

• allow survival of older companies that can’t modernize

• outside the US

  • air pollution has become the second-largest cause of death in Africa

    • 1.1 million deaths per year have been linked to air pollution across Africa, according to a Global Burden of Disease study

    • within 2 years, signatories to the declaration will establish baseline levels and ambitious reduction targets for air pollutants that meet or exceed national commitments

indoor air pollution and the ozone layer

the ozone layer

formation and composition of ozone

• oxygen (O2) + UV light = ozone (O3)

• ozone is normally present in the stratosphere → constantly being formed and destroyed

the ozone layer

• located in the stratosphere (10-15 miles above Earth’s surface)

• layer rich in ozone, but not pure ozone

• the electromagnetic spectrum

  • electromagnetic spectrum: the range of wavelengths of electromagnetic energy

the effects of ultraviolet (UV) radiation

• UV radiation is necessary in small quantities for human health, specifically vitamin D synthesis

• large quantities of UV radiation are harmful to humans and other organisms

  • causes skin cancer and cataracts

  • negatively affects immune system

  • introduces mutations in DNA of all living organisms

  • reduces crop yield and productivity

ozone depletion

chlorofluorocarbons

• aka CFCs, freons

• discovered in 1930 by a chemist working for general motors

• properties

  • chemically stable

  • odorless

  • nonflammable

  • non-toxic

  • non-corrosive

  • inexpensive to make

• common uses

  • plastic foams

  • solvents

  • air conditioning

  • refrigeration

  • medical sterilants

  • aerosols

• relationship with climate change

  • 1974 — chemists sherwood rowland and mario molina predicted that CFCs would rise to the stratosphere where they would destroy ozone molecules

  • proposed a mechanism of action for CFCs

  • early 1980’s — scientists in antarctica noticed abnormally low levels of ozone in the stratosphere

CFCs: mechanism of action

• can lose a chlorine atom under UV light

  • atom attacks the ozone molecule which then becomes oxygen

  • Cl atom is not destroyed during this reaction, is ready to attack again

• each CFC molecule lasts 65-100 years

• each Cl atom released can convert 100,000+ molecules of O3 to O2

• other ozone-depleting substances

  • halons (CFCs); present in fire extinguishers

loss of the ozone layer

• there is no such thing as an ozone hole, but a thinning of the stratospheric ozone layer

• the thickness of the ozone column is measured in dobson units

  • blue = less ozone

  • red = more ozone

• measuring ozone

protecting the ozone layer

polar vortexes

• polar vortex: a large area of cold air surrounding the Earth’s poles

• form high altitude clouds when broken

  • these clouds contain air crystals which accumulate CFCs

  • specifically, this happens in the southern hemisphere in the spring when more sunlight is present

the montreal protocol (1987)

• international treaty which phases out the use of ozone-depleting CFCs

• signed by 70+ countries (including the US)

• goal: reduce CFC production by 20% by 1993 and by 50% by 1998

  • amended in London (1990) and Copenhagen (1992)

  • amendments strengthened deadlines for elimination of CFCs and regulations for other ozone-depleting chemicals

alternatives to CFCs

• CFCs are relatively easy to replace, so there are several alternatives

• refrigerators and ACs: CFCs replaced by hydrofluorocarbons (HFCs)

  • HFCs, however, are greenhouse gases