Air, Noise, and Radiation Notes

Air, Noise, and Radiation

Introduction

Air pollution is a national and global threat due to:
- Industrial emissions (e.g., carbon dioxide) contributing to global warming.
- Chlorofluorocarbons potentially depleting stratospheric ozone.
- Acid deposition.
Air pollution poses threats to:
- Human health (asthma, bronchitis, emphysema, cancer, respiratory infections, cardiovascular disease).
- Living plants and human-made structures (forest decline, corrosion, soiling, degradation of materials).
History:
- Early air pollution control: Edward I and II of Great Britain punished air polluters.
- Before the 1930s: Air pollution was mainly considered a nuisance.
- Air pollution episodes: Meuse Valley (Belgium), Donora (PA), London, Los Angeles, New York City led to increased public awareness due to numerous deaths.

The Atmosphere and Methods of Dispersion

Chemical characteristics:
- Nitrogen (N2): 78%
- Oxygen (O2): 21%
- Argon (Ar): 0.9%
- Human impact: Technology and population growth could alter the atmospheric balance and jeopardize sustainability.
Physical Characteristics
- Solar Radiation
  - More than 99% of the sun's energy is within the spectral range of 150 to 4,000 nanometers (0.15 to 4.0 $µm$ ).
  - Solar energy absorbed by the ground radiates back as heat in longer, lower-energy infrared wavelengths.
- Greenhouse Effect
  - Infrared energy is absorbed by gases (CO2, water vapor), trapping warmth and reflecting it back to Earth.

Vertical Temperature Differences and Atmospheric Regions

Troposphere: Temperature declines with altitude at a rate of about -6.5°C/km.

Atmospheric Pressure and Density

Atmospheric mass:
- 99% below 30 km (18 miles).
- 90% below 12 km.
- 75% below 10 km.
Boiling point: Water boils at lower temperatures at high altitudes due to lower pressure.
Air flow: Air flows into low-pressure regions in a cyclonic motion and rises; cool air descends and radiates outward in an anticyclonic motion (clockwise in the Northern Hemisphere).

Atmospheric Inversions

Warmer air rises more rapidly.
Normal lapse rate, adiabatic lapse rate, and environmental lapse rate.
Types of inversions:
- Radiation inversion: Occurs at night, short-lived.
- Subsidence inversion: Occurs in fall and winter, can persist for days.

The History of Air Pollution Control in the United States

1955: Congress authorized the Public Health Service in DHEW.
1963: Clean Air Act.
1967: Comprehensive Air Quality Act.
1970: Clean Air Act Amendments (CAAA).
1977: More amendments.
1990: Clean Air Act Amendments.

Titles of the 1990 Clean Air Act Amendments

Title I: Provisions for Attainment and Maintenance of the NAAQS
- Strengthened provisions protecting against criteria pollutants (seven most widespread pollutants). See Table 10-1:
  - Carbon monoxide (CO): Transportation sources; 9.0 ppm (8-hour average).
  - Hydrocarbons: Transportation, industrial processes; 160 $µg/m^3$ (3-hour average, 6-9 am).
  - Nitrogen dioxide (NO2): Stationary source fossil fuel combustion, transportation; 0.05 ppm (annual average).
  - Sulfur dioxide (SO2): Stationary source fossil fuel combustion; 0.03 ppm (annual average).
  - Particulates:
    - PM10: Multiple sources; 50 $µg/m^3$ (annual arithmetic mean).
    - PM2.5: Multiple sources; 15 $µg/m^3$ (annual arithmetic mean), 65 $µg/m^3$ (24-hr average).
  - Ozone: Secondary pollutant; 0.12 ppm (1-hour), 0.08 ppm (8-hour).
  - Lead: Food, dust, older houses with lead paint; 1.5 $µg/m^3$ (3-month average).
- National Ambient Air Quality Standards (NAAQS).
- Non-attainment areas.
- Air quality control regions (BACT).
Title II: Provisions Relating to Mobile Sources
- Automobiles are major contributors to carbon monoxide, hydrocarbons, and nitrogen oxides.
- Strategies include: SOVs, recapture nozzles, reformulated gasoline (methyl-t-butyl ether).
Title III: Air Toxics
- Response to events like Bhopal, India (1984).
- SARA "Right to Know".
- Maximum Achievable Control Technology (MACT).
Title IV: Acid Deposition Control
- Nitrogen and sulfur oxides convert to nitric and sulfuric acids, returning to earth as acid deposition.
- Market-based principles: Emission banking and trading.
- Allowance: The right to emit one ton of sulfur dioxide.
Title V: Permits
- Regulated sources must obtain permits.
- Based on the National Pollution Elimination Discharge System (NPDES).
- State programs must be approved by the USEPA.
- Fees are charged to cover permitting costs.
Title VI: Stratospheric Ozone and Global Climate Protection
- Mario Molina, Sherwood Rowland, and Max Planck: Nobel Prize in Chemistry (1995) for establishing that CFCs destroy the ozone layer.
- CFCs are released from air conditioners, refrigerators, and industrial uses and rise to the stratosphere where UV light breaks the chlorine free which attacks ozone molecules.
- Montreal Protocol: Phase out CFCs, use substitutes; CFC production is down, but Antarctic ozone levels are expected to decline for years.
- The World Meteorological Organization reports that the ozone hole over Antarctica peaked at 7.7 million square miles and lasting for 50 days.

Health and Welfare Impacts of Ozone Depletion

Increases in basal and squamous cell skin cancer.
Suppression of the human immune response system.
Damage to the cornea and conjunctiva of the eye.
Reduction in plant leaf size, total dry weight, and stunting of plant growth.
Decreased amounts of phytoplankton and zooplankton.

Revised Ozone and Particulate Standards

Ground-level ozone: Major smog component, secondary pollutant from sunlight, nitrogen oxides, and hydrocarbons.
Standards:
- Ozone: 0.12 ppm (1 hr, 1979), 0.08 ppm (8 hr, 1997).
- Particulates: 65 $mg/m^3$ (24 hr PM2.5), 50 $mg/m^3$ (Annual PM10).

The Issue of Global Warming

Kyoto Protocol (1997): Asked Western nations to reduce greenhouse gases to pre-1990 levels by 2010.

Global Warming: The Controversy

Human activities may have upset the balance of atmospheric carbon dioxide through:
- Combustion of fossil fuels (releases carbon oxides).
- Burning of forests (produces CO2, removes a CO2 consumer).
- Destruction of phytoplankton (by ocean pollution).
Greenhouse effect: Carbon dioxide traps infrared energy, warming the earth.
Concerns:
- Icebergs breaking off the Antarctic ice shelf.
- Average global temperature increase: ~0.5°C (1°F) since the 19th century.
- Rising global sea levels (3 mm/yr).
- Warmest years: 1990, 1995, and 1997 (in the last 600 years).
- Rapidly retreating mountain glaciers.
Climate is affected by:
- Increases in atmospheric gases that absorb energy.
- Changes in the earth's orbital geometry.
- Changes in oceans temperature.
- Volcanic activity.
- Variations in solar radiation.

Factors Affecting Global Climate Change

Orbital Geometry:
- Mean global temperatures have fluctuated widely.
- Milankovitch theories: Eccentricity and obliquity.
- Ocean currents and Brodkerad and Denton's research.
El Nino:
- Changes in ocean temperatures and atmospheric conditions in the tropical Pacific, affecting global weather patterns.
- Example effects: Heavy rains in Eastern Africa, blizzards in the Western U.S., droughts in Brazil and Indonesia.
Volcanic Activity:
- Localized effects on land, short-term global changes in weather due to sunlight inhibition.
Solar Radiation:
- Sunspot cycles (11 and 22 years) correlate with nearly half of the global warming evidenced over the last 100 years.

The Criteria Pollutants

Nearly 46 million people live in counties not meeting air quality standards for criteria pollutants.
Examples (Table 10-2):
- Carbon monoxide: -31% change in ambient concentrations from 1970-1996
- Nitrogen dioxide: +8%
- Sulfur dioxide: -39%
- Particulates (PM10): -73%
- Ozone: -38%
- Lead: -98%
Criteria pollutants, sources, health and welfare effects (Table 10-3):
- Carbon Monoxide:
  - Sources: Incomplete combustion of fossil fuels.
  - Health Effects: Interferes with oxygen transport in blood.
  - Welfare Effects: Not evident.
- Nitrogen Dioxide:
  - Sources: Combustion of fossil fuels.
  - Health Effects: Increased risk of respiratory infections.
  - Welfare Effects: Reddish-brown haze, yellowing of leaves.
- Sulfur Dioxide:
  - Sources: Fossil fuel combustion.
  - Health Effects: Throat and lung irritation.
  - Welfare Effects: Corrosion of metals, damage to plants, acid deposition.
- Particulates:
  - Sources: Fossil fuel combustion, industrial processes.
  - Health Effects: Aggravates asthma and lung disease.
  - Welfare Effects: Soiling of materials, reduced visibility.
- Ozone:
  - Sources: NOx emissions, hydrocarbons, sunlight.
  - Health Effects: Breathing difficulty, irritation of mucous membranes.
  - Welfare Effects: Corrodes rubber, paint, weakens fabrics, leaf damage.
- Lead:
  - Sources: Historically from leaded gasoline.
  - Health Effects: Damage to the nervous system, blood-forming tissues, kidneys.
  - Welfare Effects: No known effect on vegetation or materials.
Particulate Matter:
- Range in size from >100 $µm$ to 0.005 $µm$ . Table 10-4 further breaks it down into course and fine particles.
 - Coarse Particles (1-100 $µm$ ):
 - Sources: Industrial and mechanical processes, agriculture, forestry, dust.
 - Chemistry: Silicon, aluminum, iron, potassium, calcium. Alkaline.
 - Fine Particles (<1 $µm$ ):
 - Sources: Combustion of fossil fuels, secondary particles, oxidation.
 - Chemistry: Elemental and organic carbon, sulfates, nitrates, oxyhydrocarbons, trace metals. Acidic.
Ozone and Photochemical Oxidants:
- Oxidant: A substance that readily gives up an oxygen atom or removes hydrogen from a compound.
- Photochemical: Initiated by sunlight.
- Good vs. Bad Ozone: The bad ozone is formed on the troposphere (nose-level). Reactions are shown in the following steps:
 - $NO_2 + h u ightharpoonup NO + O$
 - $O2 + O ightharpoonup O3$
 - $O3 + NO ightharpoonup O2 + NO_2$
 - $RO2 + NO ightharpoonup NO2 + RO$
Carbon Monoxide:
- Produced from the incomplete combustion of fossil fuels.
- Combines with hemoglobin to form carboxyhemoglobin.
- Leads to oxygen deficiency.
Lead:
- Associated with behavioral problems and reduced intellectual ability.
- Phase-out of leaded gasoline has been the predominant control strategy.
- Lead emissions from highways have decreased 99% since 1987.
Sulfur Oxides:
- Primary source: Electric utilities.
- Health concerns include respiratory illness, effects on breathing, reduced lung defenses, and aggravation of cardiovascular disease.
- Acid Deposition:
  - Sulfur oxides and nitrogen oxides are precursors to acid deposition.
  - Acid deposition occurs in rain, sleet, snow, fog, clouds, and on particles.

Effects of Acid Deposition on Ecology

Long-distance transport, acidification of acid-sensitive ecosystems.
Aquatic Systems:
- Spring thawing results in shock loading of acidity.
- Recruitment failure occurs when pH falls below 5.5.
Forests and Plants:
- Directly damages leaves.
- Mobilizes toxic metals in the soil.
- Leaches nutrients from the soil.
- Excess nitrates overstimulate plants.
Current Directions in SOx Control:
- Switching to low sulfur coal.
- Using scrubbers to remove SO2 emissions.
- Washing coal (removes up to 50% of the sulfur).
- Advanced combustion technologies.

Health Implications of Air Pollutants

Fine particulates from motor vehicles and power plants may kill 64,000 Americans a year.
Major contributor to childhood asthma.
Main Mechanisms of Air Pollutant Effects on Respiratory System:
- Inhibiting and inactivating mucociliary streaming.
- Killing or neutralizing alveolar macrophages.
- Constricting airways.
- Causing vasodilation and excess mucous secretion.
- Causing changes in alveolar cell wall structure (abscesses and thickening).

Indoor Air Pollution

People spend 90% of their time indoors; at-risk subgroups may spend nearly all their time indoors.
Sources:
- Acid, coal, gas, oil, cleaning products, furnishings, carpets, paints (VOCs), radon, moisture, molds.
Ventilation is effective for reducing indoor contaminants:
- Natural Ventilation
- Infiltration
- Mechanical Ventilation
Signs:
- Dirty/moldy heating or cooling equipment.
- Moisture condensation on walls and windows.
- Stuffy air or unpleasant odors.
- Water leakage and mold growth.
Health indicators:
- Immediate or acute effects: Eye irritation, dry throat, headaches, fatigue, sinus congestion, shortness of breath, cough dizziness, nausea, sneezing, nose irritation.
Sick Building Syndrome (SBS):
- When multiple occupants display acute symptoms without a pattern associated with a particular source.
Common Sources of Indoor Air Pollution:
- Environmental tobacco smoke, radon, biologicals, nitrogen dioxide, carbon monoxide, organic gases, formaldehyde, respirable particles, pesticides.

Environmental Tobacco Smoke (ETS)

Smoking contributes to nearly 500,000 deaths each year in the United States.
Main-stream smoke, side-stream smoke, environmental tobacco smoke (ETS).

Radon

Colorless, odorless gas from radium-226 decay.
Decays into radon daughters and gamma rays. The process is shown in Figure 10-21 graphically:
- $^{222}Rn ightharpoonup ightharpoonup ^{218}Po$
- $^{218}Po ightharpoonup ightharpoonup ^{214}Pb$
- $^{214}Pb ightharpoonup ightharpoonup ^{214}Bi$
- $^{214}Bi ightharpoonup ightharpoonup ^{214}Po$
- $^{214}Po ightharpoonup ightharpoonup ^{210}Pb$
Lodged in human tissue, radioactive materials increase the risk of lung cancer, causing 5,000 to 20,000 excess cancer deaths a year in the United States.
Detection: FCR > 4pCi/L calls for action; alpha track detectors.
Mitigation: Basement ventilation, sealing cracks/joints/walls.

Biological Contamination

Common contaminants: Molds, mildew, viruses, bacteria, dust mites, cockroaches, pollen, animal dander, cat saliva.
Major threat: Moisture.
Symptoms: Running nose, colds, flu-like symptoms, headaches, unexplained fatigue, digestive problems.

Organic Gases, Pesticides

Paints, strippers, disinfectants, cleaners, repellants, automotive products, hobby supplies, volatile office supplies, pesticides indoors can emit hazardous materials.

Formaldehyde (HCHO)

Found in pressed wood products.
Adverse health effects: Irritation to mucous membranes, severe allergic reactions, fatigue, wheezing, coughing.

Noise

When sound interferes with tasks, distracts, annoys, disturbs, causes hearing loss, or alters physiology negatively, it becomes noise.
The Physics of Sounds:
- Sound is energy produced by vibration, compressing and expanding air, water, or solids.
- Frequency and Amplitude
  - Soft sounds have low amplitude; loudness is characterized by large amplitudes. Measured in decibels (dB).

Physiology of Sound and Health Effects

Sound enters the ear, tympanic membrane vibrates.
Tympanic membrane connected to malleus, incus, and stapes, transmitting vibration to the cochlea's oval window.
Excessive sound pressure (loud noises) can destroy the delicate hairs in the spiral organ.
Hearing loss is known as permanent or temporary threshold shift (PTS or TTS).

Regulation of Noise

Requires measurement according to a standard.
Department of Labor: Permissible exposure limit of 90dBA for an eight-hour day, 40-hour work week.

Radiation

Atoms: Basic units of elements, consisting of a nucleus surrounded by electrons.
When a radioisotope decomposes, it releases energy as electromagnetic radiation (gamma or x-rays) and energy of motion from particles (alpha or beta).
An atom missing one or more electrons is an ion; energetic radiation capable of this is called ionizing radiation.

Radiation Exposure

Every individual comes into contact with ionizing radiation from:
- Naturally occurring sources (cosmic rays, minerals).
- Naturally occurring sources enhanced by human actions.
- Human-generated sources (fallout).

Health Impacts of Ionizing Radiation

Dose: High vs. low.
Dose rate: Time span for exposure may be more important than total dose.
Radiation-Induced Mutations, Birth Defects, and Cancer.

Radiation and Nuclear Power Generation

Involves a nuclear fuel cycle: Mining the uranium, processing, converting, enriching.

Ultraviolet Radiation

Wavelengths ranging between 40-400 nanometers.
Injury to hereditary material of cells causes lethal or mutational effects.
Three major types of skin cancer:
- Basal cell carcinoma
- Squamous cell carcinoma
- Malignant Melanoma
Some Beneficial Effects:
- Needed to produce Vitamin D
- Germicidal properties
- Treat bacterial skin diseases