Activity 3.3.1 Air Pollution Core Activity
1. Air Pollution Basics
Sulfur Pollutants
Sulfur pollutants are primarily emitted through the combustion of fossil fuels, such as coal and oil, and
can also be a result of volcanic eruptions. The combustion of sulfur-containing fuels releases sulfur dioxide
(SO₂) into the atmosphere, which can have harmful effects on both human health and the environment. For
example, sulfur dioxide is a key contributor to acid rain, which can damage ecosystems, soil, and aquatic habitats
(Freedman, 2018).
Nitrogen Pollutants Nitrogen pollutants include a variety of gases such as nitrogen oxides (NO and NO₂), nitrous oxide (N₂O),
and ammonia (NH₃). These pollutants primarily originate from human activities like the combustion of fossil
fuels in vehicles, power plants, and industrial processes. Nitrogen compounds contribute to the formation of
ground-level ozone, which is a major air pollutant that can irritate the respiratory system and contribute to
smog formation (Freedman, 2018).
Hydrocarbon and Volatile Organic Compound (VOC) Pollutants
Hydrocarbons and VOCs are organic compounds made up of hydrogen and carbon. They are released into
the air from sources like vehicle emissions, industrial processes, and the use of solvents. These pollutants
are concerning because they react with sunlight to form ground-level ozone. This ozone is harmful to human
health, causing respiratory problems, and can also damage crops and forests. Methane (CH₄), a potent greenhouse
gas, is also considered a hydrocarbon and is released during agricultural activities, particularly from livestock
(Freedman, 2018).
2. Comparison of Current AQI
The Air Quality Index (AQI) is a system used to measure and report the quality of the air we breathe.
It provides a scale from 0 to 500, where lower numbers indicate good air quality and higher numbers indicate
a potential health concern. The AQI takes into account different pollutants like PM2.5, ozone, sulfur dioxide,
and nitrogen oxides. An AQI over 100 is considered unhealthy for sensitive groups, and above 150 can be unhealthy
for the general population.
Comparison of Current AQI
In comparing the AQI of the three locations, New London (CT) has the highest current AQI of 174, indicating
that the air quality is unhealthy for sensitive groups. The lowest AQI is from Los Angeles, which is 56, indicating
moderate air quality. In terms of PM2.5, New Braunfels (TX) has the highest at 75, while Los Angeles has
the lowest at 56. For ozone (O3), New London has the highest reading at 174, while New Braunfels has a
much lower reading of 21.
3. Comparison of Current PM2.5 and O3 to EPA Standards
PM2.5
PM2.5 refers to fine particulate matter that is less than 2.5 micrometers in diameter. These particles are so
small that they can penetrate deep into the lungs, leading to respiratory and cardiovascular diseases. The EPA's
24-hour average standard for PM2.5 is 35 µg/m³.
Ozone (O3)
Ozone is a gas that occurs both naturally in the upper atmosphere (stratosphere) and at ground level.
At ground level, ozone forms when pollutants from vehicles and industrial facilities react with sunlight.
It can cause breathing problems, aggravate asthma, and even reduce lung function. The EPA’s 8-hour standard
for ozone is 70 ppb (parts per billion).
Table: Comparison of Current PM2.5 and O3 to EPA Standards
San Antonio’s current PM2.5 level of 23.4 µg/m³ is below the EPA standard of 35 µg/m³, indicating air
quality that is safe for most people. The current ozone level of 31 ppb is also below the EPA standard of
70 ppb, suggesting that ozone levels are within a safe range for the general population.
Resources:
Freedman, B. (2018). Environmental science: A Canadian perspective. Halifax, Canada: Dalhousie University Libraries.
US Environmental Protection Agency (EPA). (2019, June 18). Air quality index basics. Air Now. https://airnow.gov
Grammarly, www.grammarly.com/grammar-check.
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