Module 3: Air and Air Pollution

Atmosphere

It is the gaseous envelope surrounding the earth

Yes, the concentration in air can vary drastically in each location.

Is water excluded from the table of Composition of Dry Air at Sea Level?

Troposphere

What layer of the atmosphere is this?

• Closest to the Earth’s surface (7-18 km above the equator)

• Most active region, where all the dramatic events of weather (rain, lightning, and hurricanes) occur

• Contains almost 80% of the total mass of air and practically all the atmosphere’s water vapor (forms clouds and rain)

• Thinnest layer of the atmosphere (10km)

• Temperature decreases with increasing altitude

Stratosphere

What layer of the atmosphere is this?

• Consists of nitrogen, oxygen, and ozone

• 19-50 km above the equator

• Air temperature increases with altitude due to the exothermic reactions triggered by UV radiation from the sun

• One of the products of this reaction sequence is ozone (O₃), which serves to prevent harmful UV rays from reaching Earth’s surface

Mesosphere

What layer of the atmosphere is this?

• 30-50 km above the equator

• The concentration of ozone and other gases is low

• The temperature decreases again with increasing altitude

Thermosphere or Ionosphere

What layer of the atmosphere is this?

• 50-400 km above the equator

• Temperature increases with altitude - as the result of the bombardment of molecular O₂ and N₂ and atomic species by energetic particles, such as electrons and protons, from the sun

• In reverse, these processes liberate the equivalent amount of energy, mostly heat

• Ionized particles are responsible for the reflection of radio waves back toward Earth

Exosphere

What layer of the atmosphere is this?

• ≈ 400 km above the equator

• The outermost layer of our atmosphere

• This layer separates the rest of the atmosphere from outer space - 10,000 km thick

• There is a lot of empty space in between of very spread out hydrogen and helium gases

• There is no air to breathe and it is very cold

Aurora(s)

• It is a spectacular celestial light showing in the sky as a result of the ejection of myriad electrons and protons in space during solar flares or violent eruptions on the surface of the sun

• These electrons and protons collide with the molecules and atoms in Earth’s upper atmosphere, causing them to ionize and be electronically excited

• The excited molecules and ions return to the ground state with the emission of light

• An excited oxygen atom emits photons at wavelengths of 58 nm (green) and between 630 and 636 nm (red)

• The blue and violet colors often observed in _____ result from the transition in the ionized nitrogen molecule. The wavelengths for this transition fall between 391 and 470 nm

Atmosphere

This part of the Earth performs several ecosystem services:

• Protects Earth from most of the radiation from the sun and space: X-rays, Cosmic rays, and Ultraviolet (UV). Without its radiation shield, life as we know would cease to exist

• Naturally occurring greenhouse gases absorb some reradiated heat. It keeps surface temperature within a habitable range for life to exist

• It is modified and partially maintained by living organisms: Photosynthesis contributes O₂, cellular respiration produces CO₂

Ozone Layer (O₃)

• __________ in the stratosphere prevents UV radiation emitted by the Sun from reaching the Earth’s surface

• Reactive O atom combines with molecular oxygen (O₂) to form __________

• Formed __________ absorbs UV light

Health Effects

• Irritates eyes and respiratory tract

• Produces chest discomfort

• Aggravates respiratory conditions such as asthma and chronic bronchitis

• Can lead to sore throat, cough, breathing difficulty

Environmental Effects

• Reduces air visibility

• Stresses plants and reduces their vigor

• Chronic ozone exposure lowers crop yields

• Forest decline

• Greenhouse gas associated with global climate change

Greenhouse Effect

It’s the term for the trapping of heat near Earth’s surface by gases in the atmosphere, particularly CO₂.

Primary Air Pollutant

What category of air pollution is this?

Chemicals or substances emitted directly into the air from a source (natural processes and human activities) at concentrations high enough to cause harm

Natural Sources

What kind of air pollutant source is this?

• Wind-blown dust

• Pollutants from wildfires and volcanic eruptions

• Volatile organic chemicals released by some plants

It can spread out over the globe, removed by chemical cycles, precipitation, and gravity, and some chemicals emitted by volcanic eruptions or forest fires can temporarily reach harmful levels

Human (Anthropogenic) Sources

What kind of air pollutant source is this?

• Combustion of fossil fuels

• Industrial byproducts

• Mobile sources such as cars, buses, planes, trucks, and trains

• Stationary sources such as power plants, oil refineries, industrial facilities, and factories

Ozone (O₃)

What major air pollutant is this?

• Has a sharp odor that you may have detected around electric motors or welding equipment

• Can be found in the troposphere and stratosphere. In the troposphere, it is as major part of smog and in the stratosphere, it is a protective layer against UV radiation (_____ layer)

• Formed when nitrogen oxides (NOx) and volatile organic compounds (VOCs) combine chemically with oxygen in sunlight

Carbon Monoxide (CO)

What major air pollutant is this?

• It is often referred to as “the silent killer” - no color, taste, nor smell

• __________ is released when engines burn fossil fuels - automobile exhause, charcoal fires, propane pumping stoves

• When inhaled, __________ passes into the bloodstream and interferes with the ability of the hemoglobin to carry oxygen

Health Effects

• Reduces the amount of oxygen reaching the body’s organs and tissues.

• Acute exposure: dizziness, headache, decreased physical performance, vomiting, nausea and death

• Chronic exposure: stress on cardiovascular system, fatigue at low levels, heart attack

• Mental impairment due to high exposure levels (CO poisoning)

Environmental Effects

• Contributes to climate change and global warming (greenhouse gas)

• Damage to plants and crops exposed

Carbon Dioxide (CO₂)

What major air pollutant is this?

• Colorless, odorless, tasteless gas

• Greenhouse gas

• Major sources: 93% of __________ in the atmosphere is the result of the natural carbon cycle; human activities - burning of fossil fuels, clearing of __________ - absorbing forests and grasslands

Environmental Effects

• Causes climate change and global warming (greenhouse gas)

Nitrogen Oxides (NO_x)

What major air pollutant is this?

• Refer to a binary compound of nitrogen and oxygen, or a mixture of such compounds

  • NO: Nitric Oxide

  • NO₂: Nitrogen Dioxide

  • N₂O: Nitrous Oxide

  • N₄O: Nitrosylazide

• Formed when N in the fuel is burned or when N in the air reacts with O at a very high temperature. Examples are vehicle engines and coal-fired power plants

Health Effects

• Acute exposure: lung irritation

• Chronic exposure: bronchitis

• Can cause cough, shortness of breath, respiratory infections, and aggravate asthma

• Cause chronic lung disease (High exposure)

• Affect the senses (e.g. ability to smell an odor)

Environmental Effects

• Damage to vegetation (including leaf damage, decreasing growth)

• Involved in the production of photochemical smog (NO and NO₂)

• Reacts with surfaces

• Can fade and discolor fabrics and furnishings

• Harms historical buildings and structures made of limestone and marble (involved in acid deposition)

• Contributes to acid rain which can corrode metals

• Associated with global warming and ozone depletion in the stratosphere

• Reduces visibility (N₂O)

Nitrogen Monoxide (NO)

What major air pollutant is this?

• Common name or also known as: Nitric oxide

• A colorless gas

Nitrogen Dioxide (NO₂)

What major air pollutant is this?

• __________ is a reddish-brown gas that comes from the burning of fossil fuels

• Has a strong smell at high levels

• Primarily visible component of urban smog

• Can also react in the atmosphere to form ozone, acid rain, or particles

• Can combine with the moist tissue in lungs to produce an acid

Dinitrogen Monoxide (N₂O)

What major air pollutant is this?

• Common name or also known as: nitrous oxide

• Greenhouse gas emitted from fertilizers and animal wastes, and is produced by the burning of fossil fuels

• It is the largest cause of ozone layer depletion

Sulfur Oxides (SO_x)

What major air pollutant is this?

• Refer to a binary compound of sulfur and oxygen, or a mixture of such compounds

  • SO: Sulfur Monoxide

  • SO₂: Sulfur Dioxide

  • SO₃: Sulfur Trioxide

  • S₂O: Disulfur Monoxide

  • S₂O₂: Disulfur Dioxide

  • Lower sulfur oxides (S₇O₂, S₆O₂)

  • Higher Sulfur Oxides (SO₃, SO₄, etc.)

Health Effects

• Difficulty in breathing

• Acute exposure: Inflammation of respiratory tract, aggravation of asthma

• Chronic Exposure: Emphysema, bronchitis

Environmental Effects

• Main contributor to acid rain

• Secondary main contributor to particulate matter

• Harms historical buildings, structures, statues and monuments made of lomestone or marble

• Corrode metals

• Damage paints, paper, leather

• Damage to plants and crops (e.g. leaf damage), soils and aquatic life in lakes

• Decreasing growth to plants

Sulfur Dioxide (SO₂)

What major air pollutant is this?

• __________ is a corrosive gas that cannot be seen or smelled at low levels but can have a “rotten egg” smell at high levels

• Mostly comes from burning of coal or petroleum in power plants; also comes from factories that make chemicals, paper or fuel

• Like NO₂, it reacts in the atmosphere to form acid rain

• SO₂ exposure can affect people with asthma or emphysema by making it more difficult to breathe

• Also irritates the eyes, nose, and throat

• Can harm trees and crops, as well as damage buildings

Sulfur Trioxide (SO₃)

What major air pollutant is this?

• A secondary air pollutant that forms when sulfur dioxide reacts with oxygen in the air

• Reacts with water to form sulfuric acid

Particulate Matter (PM)

What major air pollutant is this?

• Solid or liquid matter that is suspended in the air

• To remain in the air, particles must be less than 0.1 mm wide and can be as small as 0.00005 mm

• Divided into 2 types: coarse particles and fine particles

• Can enter the lungs - asthma attacks, respiratory problems, premature death

• Reduces visibility and corrodes metals

Health Effects

• Heart disease, irregular heartbeat, reduced lung function, tightness of the chest

• Premature death in people with heart or lung diseases

• Asthma

• Increased respiratory symptoms (irritation, coughing or breathing difficulty)

• Severe respiratory diseases

• Chronic exposure: bronchitis

Environmental Effects:

• Poor visibility

• Making lakes and rivers acidic

• Damage to agricultural crops

• Imbalance of nutrients in coastal waters and river banks

• Contributes to acid rain

Particulate Matter: Coarse Particles

Is this coarse or fine?

Road dust, sea spray, construction

Particulate Matter: Fine Particles

Is this coarse or fine?

Burning of fuels in power plants and automobiles

Particulate Matter (PM): PM₁₀

What particulate matter number is this?

Particles with an average diameter of 10 μm (1.0 × 10⁴ nm), length on the order of 4 × 10^-4 (0.0004) inches or one-fifth of the width of a human hair

Particulate Matter (PM): PM_2.5

What particulate matter number is this?

Includes particles with an average diameter of (2.5 × 10³ nm) or less

Lead (Pb)

What major air pollutant is this?

• Blue-gray metal that is very toxic and found in a number of forms and locations

• From cars in areas where leaded gasoline is used; from power plants and other industrial sources

• _____ paint (peeling paint) and _____ in old pipes (drinking water)

• High amounts can be dangerous for small children that may cause lower IQ and kidney problems

• In adults, increased chances of heart attack and/or stroke

Health Effects

• Damages the nervous system

• IQ loss; change in behavior; impacts on learning and memory

• Risk in high blood pressure, heart disease, and kidney disease

• Reduced fertility

Environmental Effects

• Body functions of phytoplankton can be disturbed

• Imbalance in nutrients of soil

• Damages to internal organs of animals resulting to breaking of food chain

Toxic Air Pollutants (TAPs) or Hazardous Air Pollutants (HAPs)

What major air pollutant is this?

• Each toxic air pollutant comes from a slightly different source, but many are created in chemical plants or are emitted when fossil fuels are burned

• Chlorine, formaldehyde, arsenic, asbestos, benzene, and dioxin

• It can also enter food and water supplies

• Some can cause cancer

• Some can cause birth defects (teratogenic). A teratogen is a mutagen which causes birth defects

• Some can cause skin and eye irritation and breathing problems

Asbestos and Formaldehyde

What major air pollutant is this?

_____ and _____ can be found in building materials and can lead to indoor air problems

Asbestos

What major air pollutant is this?

According to the World Health Organization (WHO), _____ can cause mesothelioma (rare cancer of the lung), as well as other lung, laryngeal, and ovarian cancer. The material can also cause fibrosis of the lungs - a scarring or thickening of the lung lining, both of which cause shortness of breath. _____ was used for wall insulation, mixed with plastic, sealed into floors and built into cars. It is resistant to heat and corrosion

Dioxins

What major air pollutant is this?

• Group of chemically-related compounds that are persistent organic pollutants (POPs).

• Found throughout the world in the environment and they accumulate in the food chain, mainly in the fatty tissues of animals.

• More than 90% of human exposure is through food, mainly meat and dairy products, fish and shellfish.

• Dioxins are highly toxic and can cause reproductive and developmental problems, damage the immune system, interfere with hormones and may cause cancer.

• Burning of municipal and/or hospital waste, backyard burning and automobile emissions contribute to the release of low levels of dioxins into the environment.

Stratospheric Ozone Depletion

What major air pollutant is this?

• Chemicals that can destroy ozone in the atmosphere

• Include chlorofluorocarbons (CFCs e.g. CFCl3, CF2Cl2, C2F3Cl3 and C2F3Cl3), hydrochlorofluorocarbons (HCFCs), halons and other compounds containing Cl or Br

• CFCs are used in air conditioners & refrigerators as coolants, aerosol cans and fire extinguishers

• Other ozone depleters are used as solvents in industry

• Stratospheric ozone thinning is the accelerated destruction of ozone in the stratosphere by human produced clorine and bromine containing chemicals

Harmful Effects

• Exposure to any amount of UV radiation increases the risk of skin cancer and genetic mutations.

• Linked to ocular cataracts and weakened immunity

• Damage ecosystems, crops, materials and finishes

Volatile Organic Compounds (VOCs)

What major air pollutant is this?

• Diverse group of organic compounds emitted as gases from certain solids or liquids

• Concentration of many __________ are consistently higher indoors (>10x) than outdoors

• Variety of health effects, depending on the individual chemical

• Many are respiratory tract irritants and carcinogenic

• Most contribute to photochemical smog

Health Effects

• Eye, nose and throat irritation

• Headaches, loss of coordination and nausea

• Damage to kidney, liver and central nervous system (CNS)

• Some organics may can cause cancer in animals, some are suspected or known to cause cancer in humans

Pollens

What major air pollutant is this?

• _____ from trees, weeds and grass can cause allergies and hay fever

• _____ pollution is expected to increase with global warming as growing seasons lengthen

Molds

What major air pollutant is this?

• _____ is a problem affecting indoor air quality

• Some _____ produce toxins that bring on allergies and asthma

• _____ occur in damp buildings or those with high humidity

Urban Air Pollution

• Air pollution in an urban area is referred to as smog or industrial smog

• Industrial smog is generally worse during the winter months

• Smog is composed of sulfur oxides and particulate matter

• Industrial smog has significant problems in developing countries due to the lack of pollution-control laws that developed countries have in place

Photochemical Smog

• A brownish-orange haze formed by chemical reactions involving sunlight, nitrogen oxide and hydrocarbons is referred to as __________.

• Photochemical smog was first noted in Los Angeles in the 1940s - Worse in the summer months

• Ozone is a principal component of photochemical smog

• Results in eye irritation, aggravates respiratory illness, and harms plant tissue

• Sources include car exhaust, dry cleaners, and bakeries

• Primary pollutants: NO, CO and unburned hydrocarbons

• Secondary pollutants: NO₂ and O₃

• A catalytic converter is a unit that fits into the front part of exhaust system of a vehicle, close to the engine, to reduce the emission of gaseous pollutants, such as carbon monoxide (CO), nitrogen oxides (NO_x) and hydrocarbons (HCs).

Acid Deposition

• Sulfur dioxide and nitric oxide emissions react with water vapor in the atmosphere to form acids that return to the surface as either dry or wet deposition.

• Wet deposition - includes sulfuric acid and nitric acid in precipitation

• Dry deposition – dry particles of sulfuric acid and nitric acid that settle out of the air

• Acid rain can corrode limestone and marble (CaCO₃)

• SO₂ directly reacts with CaCO₃

Harmful Effects

• Damages statues and buildings

• Contributes to human respiratory diseases

• Leach toxic metals (such as lead and mercury) from soils and rocks into lakes used as sources of drinking water

• Harms aquatic ecosystems

• Affects forests in two ways:

  • Leaching essential plant nutrients suchas calcium and magnesium from soils

  • Releasing ions of aluminum , lead, cadmium, and mercury, which are toxic to the trees

Montreal Protocol

• A global agreement to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS). It was finalized in 1987 in this place in Canada.

• The protocol sets limits on the production of chlorofluorocarbons (CFCs), halons and related substances that release chlorine or bromine to the ozone layer of the atmosphere.

Urban Buildings

What factor is this that can increase air pollution?

Slow wind speed snd reduce dilution of pollutants

Hills and Mountains

What factor is this that can increase air pollution?

Reduce flow of air in valleys, thus allowing pollutant levels to build up

High Temperatures

What factor is this that can increase air pollution?

Promote chemical reactions leading to formation of photochemical smog

Emissions of VOCs

What factor is this that can increase air pollution?

This comes from certain trees and plants that can form photochemical smog

Grasshopper Effect or Global Distillation

What factor is this that can increase air pollution?

• Occurs when air pollutants are transported at high altitudes by evaporation and winds from tropical and temperate areas through the atmosphere to the earth’s polar areas

• Are toxins involved are polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT)

• Happens mostly during winter

• Explains why pilots have reported seeing dense layers of reddish-brown haze over the Arctic

• also explains why polar bears, sharks, and other native people in remote arctic areas have high levels of various toxic pollutants in their bodies

Temperature Inversions

What factor is this that can increase air pollution?

• It is a deviation from the normal temperature distribution in the atmosphere, resulting in a layer of cold air temporarily trapped near the ground by a warmer upper air

• Normally, warm air and most of the pollutants it contains rise to mix with the cooler air above and are dispersed

• Under certain atmospheric conditions, however, a layer of warm air can temporarily lie atop a layer of cooler air nearer the ground, creating this

• Traps air pollutants on ground level and allows their concentrations to increase

Urban Heat Islands

• Heat from sunlight heated streets, rooftops, and parking lots, radiates into the atmosphere at night

• Heat from human activities is highly concentrated in urban areas

• These pockets of heat in urban areas surrounded by cooler rural and suburban areas, are called heat islands

• Can affect local air currents and weather conditions

• Cause higher concentrations of particulate matter called dust domes

• __________ encourage the formation of a dome of heated air that surrounds an urban area

• This contributes to the buildup of air pollutants, especially particulate matter

• If wind speeds increase, the polluted air spreads over rural areas

• Cities in valleys are highly susceptible to buildup of pollutants on low wind days

• Increased number of thunderstorms in summer associated with __________

Indoor Air Pollution

__________ can lead to serious health problems

• People in rural areas and developing countries use solid fuels (wood, coal, peat, and dung) to cook indoors, with poor or no ventilation

• WHO estimates 1.6 million die annually from indoor cooking smoke

• Women and children are harmed the most by indoor cooking

• In developed countries, the most common indoor air contaminants are radon, cigarette smoke, CO, NO2, formaldehyde, pesticides, cleaning agents, ozone, and asbestos

• Viruses, bacteria, fungi, dust mites, pollen, and other organisms, are frequently found in ventilation ducts

Health Effects

• Respiratory aggravators

• Potential carcinogen

• Sick building syndrome

Sick Building Syndrome (SBS)

• __________ is used to describe situations in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building, but no specific illness or cause can be identified.

• Eye irritation, nausea, headaches, respiratory infections, depression, and fatigue caused by indoor air pollution

• The Labor Department estimates that more than 20 million employees are exposed to health risks from indoor air pollution

• Homes may contain higher levels of air pollutants than outside air, even near polluted industrial sites

Radon (Rn)

• _____ is a naturally occurring, colorless, tasteless, odorless, radioactive gas the comes out of the ground all around and below us.

• _____ comes from the natural (radioactive) breakdown of uranium in soil, rock and water and gets into the air.

• _____ is ubiquitous. It can get into any type of building, homes, offices, schools, and result in high indoor _____ levels.

• The US-EPA has determined that high levels of _____ causes lung cancer more often than second-hand tobacco smoke.

• It can infiltrate houses through cracks in basement walls or floors, openings around pipes, and pores in concrete blocks provide some of the entries for this

R.A. 8749

• Philippine Clean Air Act of 1999

• Provides the policy framework for the country’s air quality management program

• It seeks to uphold the right of every Filipino to breathe clean air by addressing air pollution from mobile and stationary sources