AH 3175E M2: Air Quality

What is the leading environmental cause of DALYs for both females and males?

Air pollution

What is the significance of air exposure compared to food and drink consumption?

Person inhales 30 m³ (35 pounds) of air/day = 6x more than amount of food & drink consumed

• Significant opportunity for exposure to agents in air through inhalation pathway

Can air be polluted both outdoors and indoors?

Yes - air may be polluted both outdoors & indoors

• Homes draw outdoor air in

• Some northeast apartments do not have forced air in

What is the significance of bad air quality on health?

Lung disease = leading cause of death in U.S.

Chronic Obstructive Pulmonary Disease (COPD) = major cause of disability in U.S.

Asthma = most chronic illness in children

• Leading cause of hospital admissions for children

• Bad air quality → exacerbates symptoms

What is a major historical air quality event in the UK that occurred in 1952?

What was it a result of?

How many acute deaths did it lead to?

Great London Fog of 1952

Result of industrial activity + atmospheric conditions

4000 acute (sudden) deaths

What disaster resulted from the release of highly toxic methyl isocyanate in India in 1984?

How many acute deaths did it lead to?

Bhopal Disaster of 1984

4000-16000 acute deaths

What is the normal movement of warm air?

What is a temperature inversion?

How does it affect pollution?

Warm air = close to surface + cold air = above → warm air rises as altitude increases

Temperature inversion = layer of cold air trapped at surface w/ warm air layer above

Prevents vertical movement of air → pollution kept near surface

What type of landform is especially susceptible to temperature inversions?

Valleys → due to absence of crosswinds dissipating clouds

• No circulation to push clouds away

What season are temperature inversions more frequent?

What usually warms up the ground air?

What happened in Great London Fog?

Winter = ground cools down → cools air close to ground → temperature inversion

Morning sun = breaks through mist & heats ground → warms air close to ground → breaks temperature inversion

Too much smoke (black soot, stick particles of tar, gaseous sulfur dioxide) accumulated close to ground → sun unable to break through → air stayed cool & static

What is smog?

Smog = fog w/ soot = “smokey fog”

Explain what is happening in this graph depicting the number of deaths and levels of smoke during the days in December 1952 during the Great London Fog

Increased sulfur dioxide + smoke → increased deaths

What 2 groups were most affected during the Great London Fog?

Elderly & Infants

What were 2 factors that contributed to major historical air quality events?

During what season(s) did they most often occur?

• Home heating

• Industrial activity

During Fall/Winter times

What happened to lead to the 1984 Bhopal Disaster?

How many tons of methyl isocyanate was released into surrounding areas?

How many deaths and injuries did the methyl isocyanate exposure lead to?

Union Carbide = pesticide manufacturing plant in Bhopal, India

• Methyl isocyanate = intermediate compound in pesticide synthesis → stored 40 tons

• Poor factory condition → water introduced to methyl isocyanate tank → increased pressure in storage tank

30 tons released → surrounding areas

3000 deaths + 200,000 injuries

What act of federal legislation was enacted in 1955 to address air pollution?

What was the issue with this act?

Air Pollution Control Act (1955) = authorized U.S. Public Health Service:

• Conduct air pollution research & control measures

• Technical assistance → communities facing air pollution

• Collect air quality data

Air Pollution Control Act did NOT have federal powers to enforce air quality standards

What book captured public’s attention to chemical pollution in 1962?

Silent Spring by Rachel Carson

What river caught on fire in 1969?

Cuyahoga River caught fire → caught public attention

What agency was established by President Richard Nixon in 1970?

Environmental Protection Agency (EPA) = protect human health by protecting air, water, and land

What act in 1970 led to a major shift in U.S. air pollution regulation?

What standards did the act set?

What are the 5 individual pollutants that the standards include?

Clean Air Act of 1970 → dramatic expansion of air quality standard enforcement

National Ambient Air Quality Standards (NAAQS) → standards for stationary pollution sources

Carbon monoxide (CO), lead (Pb), nitrogen dioxide (NOx), ozone (O3), Particulate Matter (PM) and PM2.5, and sulfur dioxide (SO2)

What did the Clean Air Act of 1970 improve?

• Health-based approach

• Engineering/technical controls & economic considerations

• Stationary & mobile sources

• Monitoring & modeling activities

• Federal & state permit programs

• Economic incentives & emission trading

• Special topics - acid rain, ozone depletion, catastrophic releases

What are Title 3 “Hazardous air pollutants”?

List of toxic air pollutants (188) regulated by industry categories

• Consideration of residual risk & susceptible populations

What are the 2 broad classes of air pollutants the Clean Air Act of 1970 establish?

• Criteria Pollutants (CAPs)

• Hazardous Air Pollutants (HAPs)

What are 3 important properties of criteria pollutants?

• Ubiquitous = emitted from variety of sources (from both mobile & stationary sources)

• Omnipresent = pose greatest overall threat to human health

• Presupposition = adverse health effects = NOT cancerous & dose-response relationship exhibits threshold dose

What are the 6 major criteria pollutants?

1. Particulate matter (PM)

2. Sulfur dioxide (SO2)

3. Nitrogen Dioxide (NO2)

4. Ozone (O3)

5. Carbon monoxide (CO)

6. Lead (Pb)

What is the difference between primary standards and secondary standards of National Ambient Air Quality Standards (NAAQS)?

What have these standards led to?

Primary standards = protect public health w/ adequate safety margin + health of sensitive populations (asthmatics, children, & elderly)

Secondary standards = protect public welfare from adverse effects (visibility impairment, environmental effects on vegetation, soils, wildlife)

National improvements in air quality based on [criteria pollutants]

What is the number 1 source of the following?

1. Carbon Monoxide

2. Nitrogen Oxides

3. VOCs (not a criteria pollutant!)

4. Sulfur Oxides

5. Particulates

1. CO → Transportation

2. NO2 → Transportation

3. VOCs → Transportation

4. SO2 → Fuel combustion stationary sources

5. PM & PM25 → Fuel combustion stationary sources

What are State Implementation Plans (SIPs)?

What does it outline?

What can the EPA use if the state fails to meet the SIP?

State Implementation Plans (SIPs) = must be submitted by individual states once EPA establishes/revises NAAQs

• Outlines specific local emission controls, permits, & rules to be enforced

• Fails to meet plan → EPA steps in with Federal Implementation Plan (FIP)

What are “Market-Based” Trading of Pollution Credits?

“Market-Based” Trading of Pollution Credits = system of earning “credits'“ for releasing low pollution levels

• Sold through brokers to older/more polluting companies that have not made sufficient capital investment → upgrade pollution control technologies

What is the overall trend for the following since 1970:

1. GDP

2. Vehicle miles

3. Population

4. Energy Consumption

5. CO2 emissions

6. Aggregate emission

1. GDP → increased

2. Vehicle miles → increased

3. Population → increased

4. Energy Consumption → increased

5. CO2 emissions → increased (small)

6. Aggregate emission → decreased

How do Hazard Air Pollutants compare to Criteria Pollutants in:

• Sources

• Toxicity?

• More toxic

• Carcinogenic

What are some examples of Hazardous Air Pollutants?

Benzene, Formaldehyde, Cadmium, Vinyl chloride, Methyl isocyanate

Are strategies used to regulate Criteria Pollutants & Hazardous Air Pollutants the same?

No - due to differences in sources and toxicity

What type of air pollution is the Great London Fog an example of?

Criteria Pollutants → Particulate matter + Sulfur oxide emissions

What type of air pollution is the Bhopal Disaster an example of?

Hazardous Air Pollutants → Methyl isocyanate

How is pollution transported?

What direction across the U.S. do pollutants travel in?

What system does this follow?

Pollution transported by weather systems

West → East (Also applies to China → South Korea)

Storm Systems

What does the EPA monitor for Criteria Air Pollutant Standards?

EPA monitors which counties in violation of Criteria Air Pollutant standards

Describe adherence of CT and greater Northeast to ozone standards & particulate matter

Connecticut and the surrounding Northeastern states persistently fail to meet or have nonattainment of the federal health and safety limits for clean air.

What kind of system and type of terrain transport pollution?

Slide 58-62

Slide 58-62

What is “normal air” made of?

• N₂ (78%)

• O₂ (21%)

• Noble gases (He, Ne, Ar, Kr)

• CO₂ (0.04%)

What are 5 important natural sources of air pollution?

1. Windstorms → dust clouds

2. Salt evaporation along coasts

3. Production of biological materials (Ex. Organic material from plants)

4. Forest fires

5. Volcanic eruptions

What are anthropogenic sources of air pollution?

What are some examples?

What are 5 mitigating solutions?

Anthropogenic sources of air pollution = human sources of air pollution

• Agriculture

• ‘Area’ sources (Commercial, residential)

• Energy production

• Industry

• Transportation

Mitigating solutions:

• Alternate energy & conservation strategies

• Urban & industrial planning

• Process changes

• Recycling

• Top of stack/end of tail pipe

What are environmental implications of air pollution?

• Ozone/smog

• Acid rain

• Upper atmosphere ozone depletion

• Aesthetic/visibility → regional haze

• Climate/greenhouse effect

• Accidental toxic releases

• Polluted air

What are health implications of air pollution?

• Respiratory symptoms + lung disease

• Cardiovascular effects (Ex. hypertension)

• Central Nervous system effects

• Organ damage

• Death

What is carbon monoxide formed through?

What are 2 conditions that favor carbon monoxide emissions?

Incomplete combustion of hydrocarbon fuels

Conditions:

• < optimal O₂ levels

• < combustion temperatures

What are examples of carbon monoxide health effects @ low vs. high concentrations?

Low concentrations:

• Fatigue

• Chest pain in people w/ heart disease

High concentrations:

• Impaired vision & coordination

• Headaches, dizziness, & confusion

• Nausea

• Fatal @ high exposures

Describe the carbon monoxide mechanism of toxicity

CO = 200x affinity for binding Hb in blood than O₂

• Interferes blood’s ability to transport + transfer O₂

What should you do if power goes out?

DO NOT use natural gas stove to heat home

Ensure generator = outside NOT in garage

DO NOT run car in garage

What is the primary source of SO₂?

Combustion of sulfur species in coal-fire power plants

What do sulfur dioxides oxidize further into?

Sulfur dioxides → aerosols/particulate matter

What are 2 major forms of nitrogen-oxide species?

•NO and •NO₂

What is the primary source of •NO?

Combustion reactions → •NO = byproduct

What are the implications of SO_x and NO_x on acid rain?

1. SO₂ + NO₂ emissions → air

2. Pollutants → acid particles → transported long distances

3. Acid particles = fall on Earth as dust, rain, snow, and other materials

4. Acid rain particles → harmful effects on soil, forests, streams, & lakes

What does SO₂ and NO₂ cause in health?

• Throat & lung irritation

• Aggravation of asthma & chronic bronchitis symptoms

What is the difference between strastpheric and tropospheric ozone?

Stratospheric ozone = layer above, includes ozone layer

• Ozone (O₃) = protects planet from UV-B & UV-C light

• Prevents UV light from reaching Earth’s surface

Tropospheric ozone = lowest layer of Earth’s atmosphere where weather occurs

• Ozone (O₃) = potent respiratory irritant = strong oxidant = common to disinfect drinking water in water treatment plants

What is the main component of photochemical smog?

Ozone (O₃)

• From photochemical reactions b/w NO₂ + VOCs

What is our most likely scenarios of exposure to tropospheric ozone?

• Outside on low air-quality days during daylight

• Occupational exposures (Ex. water treatment plant, heavy use of old photocopiers)

How do chloro-fluoro-carbons (CFCs) destroy ozone?

CFCs = rise to stratosphere

UV light → breaks Cl free from CFC molecule

Cl destroys ozone catalytically

What is ozone catalytically destroyed by in the stratosphere?

Chlorine

What is the “Leaky Bucket” concept in stratospheric ozone depletion?

Leaky bucket = stratosphere = how ozone balance is maintained

• Higher [ozone-depleting substances] → Larger holes in bucket

• Equilibrium = re-established → ozone level lowers

What was the Vienna Convention for the Protection of the Ozone Layer of 1985?

Framework for efforts to protect ozone layer

• Recognized need to protect O₃ layer

• Established regular meetings for ozone layer issues

• Established framework for scientific research

Took place during same year Ozone Hole discovered

What was the Montreal Protocol on Substances that Deplete the Ozone Layer of 1987?

International agreement = supplements Vienna Convention

• Regulates production/consumption of ozone depleting substance

• Required reporting production + consumption of ozone depleting substances + re-examined control measures

• Established 4-year assessment process

Meeting took place same year Cl = cause of stratospheric ozone depletion

What is the difference between the stratospheric and tropospheric ozone layers?

Stratospheric ozone → O3 = absorbs & protect planet from UV-B (sunburns + cancer) and UV-C (germicidal) light

Tropospheric ozone = O3 = no purpose = potent respiratory irritant

What is the main component of photochemical smog?

Ozone = produced by photochemical rxns b/w NO2 + VOCs

What are VOCs?

VOCs = organic compounds w/ higher vapor pressure

• Automobiles = important source through partial fuel combustion

Explain what is happening in this diagram

VOCs combine with O2 and NO2 + photon of light → produce O3 (Ozone)

Explain what is happening in this diagram of Tropspheric Ozone Formation

• Occurs only when there is light outside (UV radiation)

What are 4 health effects of ozone exposure?

• Difficulty breathing

• Mucous membrane irritation

• Increased risk of respiratory infections

• Acute exposure → respiratory pain, bronchoconstriction, lung edema

What state and region have nonattainment of ozone and particulate matter standards?

CT and Northeast region

• EPA = monitors which counties = violation of Criteria Air Pollutant Standards

What are aerosols?

What is particulate matter (PM)?

What is the difference?

Aerosols = collection of suspended particles + surrounding gases

Particulate matter (PM) = mixture of solid particles + liquid droplets in air

• Varying sizes + chemical compositions

Aerosols INCLUDE surrounding gas

PM DOES NOT INCLUDE surrounding gas

What are 8 sources of particulate matter?

• Bubble Bursting

• Forest Fires

• Primary biological aerosols

• Dust

• Volcanic Ash

• Secondary Organic Aerosol (SOA)

• Secondary Organic Aerosol

• Combustion Aerosol

• Tire degradation → PM

What produces dramatically more particulates than gasoline vehicles?

Diesel vehicles = 20x more than gas

• Diesel vehicles sold in EU/US have diesel particle filters

Combusion particulates are _______ assemblages and can deliver numerous _________ to the lung.

Complex; toxicants

• Exposed to all compounds stuck to exterior

Our county + CT frequently exceeds NAAQS for ozone and particulate matter (True/False)

True → pollution from cities + manufacturing from Midwest + East Coast Cities + I-95

What 2 sizes are Particulate Matter divided into?

What 2 additional categories can it be divided into?

PM2.5 → diameter < or equal to 2.5 micrometers

PM10 → diameter > or equal to 2.5 micrometers, but less than or equal to 10 micrometers

Fine particles (0.1 micrometer - 2.5 micrometers)

Ultrafine particles (0.01 micrometers - 0.1 micrometers)

What size of PM is a greater health concern?

PM2.5 + smaller → can be inhaled into lungs

• If not dissolved → difficult to be cleared efficiently

• If dissolved → exposure to intoxicants

Sources of particulate matter are _________

Diverse

What are 4 ways the lead was eliminated from gasoline?

What did this also indirectly help with?

• Prevent early fuel ignition in engine

  • “Knocking”

• Protected + lubricated “valve seats” to prevent early wear

• Discovered alternative anti-knock agents (MTBE + ethanol)

• Various changes in engine design (Wear-resistant materials + engine oil)

Indirectly allowed improvements in CO + NOx vehicle emissions

What is the significance of implementing catalytic converters in vehicles?

What is oxidized vs. reduced in catalytic converters?

• Modern catalytic converters = “Three-way converters”

  • Eliminate unburned escaped fuel (hydrocarbons)

  • Control CO

  • Control NOx

  • Hydrocarbon + NOx = ingredients for ozone formation

  • CO interferes with blood oxygen transport

  • NOx = acid rain

Hydrocarbons + CO = oxidized → CO2

NOx = reduced → N2

What is the significance of implementing scrubbers in power plants?

Scrubber systems = installed in power plant systems → remove SO2 from flue gas

• Removes 95-99% of SO2 from power plant flue gas → reduce impact of coal on acid rain

What has changing from coal-fired power plants to natural gas-fired power plants done?

Methane = natural gas = cleaner-burning fuel than coal

• More complete combustion (less carbon particulates)

• Lower sulfur content (less SO2 emissions + particulates)

About how much of our time do we spend indoors?

What kind of environments trap pollutants? Why? 2 reasons

75-90%

Indoor environments trap pollutants = 2-5x higher levels than outside

• “Air Tightening” of buildings reduce heating/cooling needs

  • Lower outside air infiltration rate → not as much ventilation

• Off-gassing from synthetic building materials

  • Synthetic smell from materials

What are 2 important indoor air pollutants?

• Asbestos pipe insulation

• Radon infiltration

What are 6 sources of indoor air pollution?

1. Combustion by-products

2. Microorganisms + allergens

3. Formaldehyde + VOCs

4. Asbestos

5. Tobacco Smoke

6. Radon

7. Others

What are 2 important reasons that indoor air pollution should be a concern?

Biological allergens = dust mites, cockroaches, animal dander, protozoa, insects, algae, pollen = hypersensitivity pneumonitis → cough, dyspnea, fatigue, allergic rhinitis, asthma

Tobacco smoke = indoor smoking irritation, congestion, inflammation

What has the change in air exchange rate since the 1970s-1980s to after 1980s?

Decrease in air exchange rate

There are specific federal laws regulating indoor air quality of public buildings (True/False)

What must private residences rely on to improve indoor air quality?

What are some examples of mitigation strategies?

False

Must rely on education

Mitigation strategies = removing indoor pollution sources, increasing ventilation, air cleaning (filtration)

What is Sick Building Syndrome?

What buildings can be designed as a “sick building”

Sick Building Syndrome = symptoms associated w/ time spent in specific buildings

• Respiratory tract irritation, skin irritation, headache, dizziness, nausea, fatigue, issues w/ concentration

• Symptoms diminish/cease when leaving building

• Cannot be traced to specific pollutants/sources within building

If more than 20% of occupants report SBS symptoms

What percentage of global population use open fires or insufficient stoves (w/o chimneys) using kerosine, biomass, or coal (Harmful sources of air pollution)?

What groups are more exposed to this in low-income countries?

According to WHO: ~1/3 global population (2.3 billion people)

Women & children = burdened w/ domestic responsibilities

What health-damaging pollutants does indoor smoke contain?

• Particulate matter

• Carbon monoxide

• Nitrogen oxides

• Sulfur Oxides (Coal)

• Formaldehyde

• Carcinogens (benzo[a]pyrine + benzene)

Which of the fuel sources are worst for PM and CO formation?

A. Wood

B. Coal

C. Oil

D. Gas

Wood

Which of the fuel sources are worst for SOx formation?

A. Wood

B. Coal

C. Oil

D. Gas

Coal

What are 3 examples of ways to monitor air pollution exposure?

• Aerodyne specializes in monitoring systems using mobile monitoring vehicle

• Fresh Air Wristband = wearable air pollutant sample

• Stationary + portable multipollutant monitors

What are 4 different levels of exposure of air pollution?

• Acute exposure = contact w/ substance occurs once/short time

• Acute toxicity = adverse effects shortly after exposure (hours-days)

• Chronic exposure = contact w/ substance for long time (>1 year)

• Chronic toxicity/health effect = health condition over long period of time

What are the 4 factors that affect the type and extent of injury?

Injuries can be ____ or ____

• Concentration of pollutant

• Dose received by individual

• Duration of exposure

• Physiochemical properties of chemical

Injuries can be acute or chronic

What must the respiratory system provide to combat air pollution?

Exposure pathway for systemic exposures + respiratory system exposure

What are the 3 primary divisions of the airway?

• Nasopharyngeal

• Tracheobronchial

• Alveolar region/gas exchange surfaces

Particles are removed by region of airway based on ______

What happens to approximate size of deposited particles as you go deeper down the respiratory tract?

Size

Approximate size decreases