TECHNOLOGICAL UNIVERSITY OF THE
PHILIPPINES-VISAYAS
BES-133ME – ENVIRONMENTAL SCIENCE
ANG ENGINEERING
WEEK 4 PROGRESS CHECKS
Submitted by: Josh Cymon Flor – ME1D
Submitted to: Engr. Aron J. Leonoras, PME
4th Day of April, 2025
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WEEK 4
1. Discuss the effects of air pollutants on:
a. Materials
Air pollutants, especially sulfur dioxide (SO₂) and nitrogen oxides (NOₓ), cause
significant damage to materials over time. These gases react with moisture in the air to form
acidic compounds, which accelerate the corrosion of metals and the weathering of stone
structures like buildings and monuments. For example, marble and limestone can react with
acid rain to form gypsum, leading to structural deterioration. Particulate matter, such as soot
and dust, also contributes to material degradation by soiling surfaces, making them harder
to clean and requiring frequent maintenance. Over time, this results in higher economic
costs for preservation and restoration (Seinfeld & Pandis, 2016).
b. Vegetation
Plants are particularly vulnerable to air pollutants like ozone (O₃), sulfur dioxide, and
nitrogen oxides. Ozone, which forms through photochemical reactions, damages plant cells
by affecting their ability to perform photosynthesis. This can lead to reduced crop yields and
stunted plant growth. Sulfur dioxide can enter leaf pores (stomata), dissolve in plant fluids,
and cause tissue damage, resulting in symptoms like leaf yellowing (chlorosis) and
premature leaf drop. Acid rain also affects soil pH, depleting essential nutrients and making
it harder for plants to thrive (Krupa, 2003).
c. Human Health
Air pollution poses serious health risks, particularly to the respiratory and
cardiovascular systems. Fine particulate matter (PM2.5) can penetrate deep into the lungs,
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leading to conditions such as asthma, bronchitis, and even lung cancer. Long-term exposure
to pollutants like nitrogen oxides and ozone is linked to an increased risk of heart disease
and stroke. Carbon monoxide (CO) interferes with oxygen transport in the blood, causing
symptoms like dizziness and confusion, and can be fatal at high concentrations. Vulnerable
populations, including children, the elderly, and individuals with preexisting conditions, are
especially at risk (WHO, 2021).
2. Define the term Acid rain and explains how it occurs.
Acid rain refers to precipitation with elevated levels of sulfuric (H₂SO₄) and nitric acid
(HNO₃), primarily caused by emissions of SO₂ and NOₓ from burning fossil fuels. These
pollutants react with atmospheric moisture to form acidic compounds that fall to the
ground as rain, snow, or fog. The consequences of acid rain include damage to aquatic
ecosystems, where it lowers pH levels and disrupts aquatic life, as well as soil
degradation, which affects plant growth.
Structural damages to buildings and monuments are also significant. Mitigation
strategies involve emission reduction policies, the use of clean energy, and technological
solutions like flue gas desulfurization (EPA, 2023).
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3. Discuss the following atmospheric conditions in air pollution meteorology:
a. Atmospheric engine
The atmosphere acts as a dynamic engine, driven by solar radiation, which causes
temperature variations and air movement. These temperature differences create pressure
systems, which influence weather patterns and pollutant dispersion. The efficiency of the
atmospheric engine determines how pollutants are transported and dispersed over large
areas (Jacob, 1999).
b. Turbulence
Turbulence refers to irregular air movements that enhance the mixing and dilution of
pollutants. Factors like wind speed, surface roughness, and atmospheric instability
influence turbulence levels. High turbulence helps disperse pollutants, reducing localized
air quality issues, whereas low turbulence allows pollutants to accumulate, leading to smog
formation (Stull, 1988).
c. Stability
Atmospheric stability determines the vertical movement of air masses. A stable
atmosphere suppresses vertical mixing, trapping pollutants near the surface and causing
high concentrations. In contrast, an unstable atmosphere promotes vertical mixing,
dispersing pollutants more effectively. Temperature inversions, where warm air overlays
cooler air, often lead to severe air pollution episodes (Seinfeld & Pandis, 2016).
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4. Name at least ten variables that affect the internal combustion (automobiles)
emissions.
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Fuel composition
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Air-to-fuel ratio
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Engine temperature
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Combustion efficiency
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Engine load Ignition timing
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Exhaust gas recirculation (EGR)
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Catalytic converter efficiency
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Atmospheric conditions (temperature, humidity)
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Maintenance and age of the engine Each of these factors affects the
production of pollutants like CO, NOₓ, and hydrocarbons
5. List and define three units of measure used to report air pollution data.
Parts per million (ppm) - Measures the concentration of a pollutant in air
(e.g., CO at 9 ppm).
Micrograms per cubic meter (μg/m³) - Represents the mass of a pollutant
per unit air volume (e.g., PM2.5 at 12 μg/m³).
Air Quality Index (AQI) - A standardized index indicating air quality based on
pollutant concentrations and their health effects (EPA, 2023).
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6. Explain the difference between ppm in air pollution and ppm in water pollution.
Parts per million (ppm) is a unit of concentration used in both air and water pollution
measurements, but its interpretation differs depending on the medium. In air pollution,
ppm represents the volume ratio of a pollutant to air. For example, 1 ppm of carbon
monoxide (CO) in the atmosphere means that for every one million air molecules, one is a
CO molecule. Since gases mix uniformly, this measurement is straightforward and helps
regulate exposure limits, such as the U.S.
Occupational Safety and Health Administration (OSHA) limits for workplace air
quality. In contrast, ppm in water pollution refers to the mass of a contaminant per million
parts of water, often expressed as milligrams per liter (mg/L) since 1 ppm is approximately
equal to 1 mg/L in dilute solutions. For example, if lead in drinking water is measured at
0.015 ppm, it means there are 0.015 mg of lead per liter of water. Unlike gases in air,
contaminants in water may not be evenly distributed, requiring thorough sampling and
testing. The differences in how ppm is applied in air versus water highlight the need for
context-specific regulatory standards to ensure environmental and human health safety
(Seinfeld & Pandis, 2016).
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7. Discuss the natural and anthropogenic origin of the six criteria air pollutants
and identify the likely mechanisms for their removal from the atmosphere.
The U.S. Environmental Protection Agency (EPA) classifies six major air pollutants
as criteria pollutants due to their widespread health and environmental impacts: carbon
monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), particulate
matter (PM), and lead (Pb). These pollutants originate from both natural and
anthropogenic (human-made) sources. Natural sources include volcanic eruptions,
which release sulfur dioxide and particulate matter; wildfires, which produce carbon
monoxide and fine particles; and biological decay, which emits nitrogen oxides and
volatile organic compounds that contribute to ozone formation. While these natural
emissions have always existed, human activities have significantly amplified their
concentrations in the atmosphere.
Anthropogenic sources are largely due to fossil fuel combustion from vehicles,
power plants, and industrial activities. CO primarily comes from incomplete combustion
in automobile engines, while NO₂ forms when nitrogen in fuel reacts with oxygen at high
temperatures. Coal-fired power plants are major sources of SO₂, and industrial
processes release lead and fine particulate matter into the air. Ozone, though not directly
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emitted, forms through photochemical reactions involving NOₓ and volatile organic
compounds in the presence of sunlight.
These pollutants are removed from the atmosphere through natural mechanisms
like wet deposition (rain washing pollutants from the air), dry deposition (settling of
particles onto surfaces), and chemical reactions that convert harmful substances into
less reactive forms. However, the overwhelming contribution of human activities
necessitates strict air quality regulations to mitigate their impact (EPA, 2023).
8. Explain the term greenhouse effect, its hypothesized cause, and its pros and
cons to the atmosphere.
The greenhouse effect is a natural process where certain gases trap heat in Earth’s
atmosphere, keeping the planet warm enough to support life. Greenhouse gases (GHGs)
such as carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), and water vapor absorb
infrared radiation emitted from the Earth's surface and re-radiate it back, preventing heat
loss into space. Without this effect, Earth’s average temperature would be about -18°C (0°F)
instead of the current 15°C (59°F). The primary concern today is the enhanced greenhouse
effect, which results from excessive GHG emissions due to human activities, particularly the
burning of fossil fuels, deforestation, and industrial processes. The increase in CO₂ levels
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from pre-industrial levels of 280 ppm to over 415 ppm today has intensified global warming,
leading to climate change.
This manifests in rising global temperatures, melting glaciers, rising sea levels, and
increased frequency of extreme weather events. Despite its negative impacts, the
greenhouse effect is essential for life on Earth. Without it, our planet would be too cold to
sustain ecosystems and human civilization. Additionally, greenhouse gases help regulate
temperature fluctuations, maintaining relatively stable climatic conditions.
However, the excessive accumulation of these gases is leading to dangerous
environmental changes, making it necessary to adopt strategies such as carbon
sequestration, emission reduction policies, and renewable energy adoption to mitigate its
effects (IPCC, 2021).
9. Discuss the Montreal Protocol.
The Montreal Protocol is one of the most successful international environmental
agreements, designed to protect the ozone layer by phasing out substances responsible for
ozone depletion. Signed in 1987 and enforced in 1989, the protocol primarily targets
chlorofluorocarbons (CFCs), halons, and other ozone-depleting substances (ODS) used in
refrigeration, air conditioning, aerosol sprays, and industrial applications. CFCs and similar
chemicals break down in the stratosphere, releasing chlorine and bromine atoms that
catalytically destroy ozone molecules. The resulting ozone depletion increases harmful
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ultraviolet (UV) radiation reaching the Earth's surface, leading to higher risks of skin cancer,
cataracts, and weakened immune systems, as well as harming marine life and ecosystems.
The Montreal Protocol has been remarkably effective, with nearly 200 countries
committing to its implementation. As a result, atmospheric concentrations of CFCs have
declined, and the ozone layer is on track to recover by the mid-21st century. The protocol
has also played a role in mitigating climate change since many ODS are also potent
greenhouse gases. Subsequent amendments, such as the Kigali Amendment in 2016, have
expanded its scope to include hydrofluorocarbons (HFCs), which, although not ozonedepleting, contribute significantly to global warming (UNEP, 2020).
10. Enumerate ways to minimize air pollution in a coal-fired power plant.
Coal-fired power plants are among the largest sources of air pollution, emitting
sulfur dioxide (SO₂), nitrogen oxides (NOₓ), particulate matter (PM), mercury, and carbon
dioxide (CO₂). Reducing pollution from these facilities requires a combination of
technological, regulatory, and operational strategies.
Flue Gas Desulfurization (Scrubbers): These systems remove sulfur dioxide
from emissions by reacting it with limestone or other alkaline substances, significantly
reducing acid rain formation.
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Selective Catalytic Reduction (SCR): This technology reduces nitrogen oxide
emissions by converting them into nitrogen and water using catalysts such as ammonia
or urea.
Electrostatic Precipitators and Baghouse Filters: These devices capture fine
particulate matter before it is released into the atmosphere, improving air quality and
reducing respiratory health risks.
Carbon Capture and Storage (CCS): This emerging technology captures CO₂
emissions before they reach the atmosphere and stores them underground or uses them
in industrial applications.
Fuel Switching: Using low-sulfur coal or blending it with biomass can reduce SO₂
emissions. Some power plants are transitioning to natural gas, which burns more cleanly
than coal.
Efficiency
Improvements:
Upgrading
turbines,
optimizing
combustion
processes, and using advanced control systems can enhance energy efficiency and
reduce emissions.
Renewable Energy Integration: Investing in solar, wind, and hydroelectric power
can help phase out coal dependence, reducing air pollution and greenhouse gas
emissions over time.
Regulatory frameworks, such as the Clean Air Act in the U.S., set emission limits
and require continuous monitoring and reporting. As nations strive for carbon neutrality,
coal-fired plants are facing increasing pressure to adopt cleaner technologies or
transition to renewable alternatives (EPA, 2023).
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References
Environmental Protection Agency (EPA). (2023). Air pollutants: Criteria air pollutants.
Retrieved from https://www.epa.gov/
Heywood, J. B. (2018). Internal combustion engine fundamentals (2nd ed.). McGraw-Hill
Education.
Intergovernmental Panel on Climate Change (IPCC). (2021). Climate change 2021: The
physical science basis. Cambridge University Press.
Jacob, D. J. (1999). Introduction to atmospheric chemistry. Princeton University Press.
Krupa, S. V. (2003). Effects of atmospheric ammonia (NH₃) on terrestrial vegetation: A
review. Environmental Pollution, 124(2), 179-221.
Seinfeld, J. H., & Pandis, S. N. (2016). Atmospheric chemistry and physics: From air
pollution to climate change (3rd ed.). John Wiley & Sons.
Stull, R. (1988). An introduction to boundary layer meteorology. Springer.
United Nations Environment Programme (UNEP). (2020). Montreal Protocol on
substances that deplete the ozone layer. Retrieved from https://www.unep.org/
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