Activity 3.3.1 Air Pollution Core Activity

Below are topics that were discussed in chapter 16 of “Environmental Science: A Canadian Perspective” written by Bill Freedman. After reading chapter 16, I summarized air pollution basics, compared current AQI in different regions, and compared current PM2.5 and O3 to EPA standards.

Air Pollution Basics

Air pollutants can naturally be released into the air through forest fires or volcanoes but as the population grows so does air pollution due to industrialization and other related factors.

Sulfur Pollutants- Some sulfur gasses are colorless but have a strong smell like sulfur dioxide and hydrogen sulfide. When those two gases are emitted into the atmosphere, they react and become oxidized into different compounds to form sulfate which is an anion because its ion holds negative charges. The atmospheric sulfate is able to combine with cations, ions that are positively charged, to be able to form different kinds of compounds. Volcanoes emit sulfur gases which almost completely consist of sulfur dioxide and the rest is hydrogen sulfide. Anthropogenic emissions of sulfur dioxide have dramatically increased since the start of the Industrial Revolution when about 5 million tonnes were emitted and in 2000 there were about 150 million tonnes emitted. Accidental emissions from gas plants where hydrogen sulfide is removed from the natural gas have a high possibility of causing damage to the vegetation in the area because of its toxicity. Additionally, sulfur dioxide is high enough in cities located near such industries that it affects the wild and plants. Humans and some animals are not as sensitive to sulfur dioxide but still, long-term exposure can be detrimental. 

Nitrogen Pollutants- Important nitrogen gases discussed in the reading include nitric oxide, nitrogen dioxide, nitrous oxide, and ammonia. Ammonia, a colorless gas, is created through the anaerobic decomposition of biomass that is dead which is naturally released into the air around 1.2 billion tonnes yearly. The amount of time that ammonia is in the atmosphere is close to 7 days where it will end up being oxidized into nitrate. Nitrous oxide is another colorless gas but it is also a non-toxic gas that when inhaled provides a euphoric reaction also known as “laughing gas”. Nitrous Oxide is used in modern medicine as an anesthetic or recreationally. This gas spends around 4 years in the atmosphere because it is an unreactive compound and industrial emissions of nitrous oxide are about 12 million tonnes yearly. Nitric oxide is colorless, odorless, and irritates respiratory and eye membranes. The combustion of fossil fuels from power plants or cars creates about 83 million tons of anthropogenic emissions of NOx yearly. It is uncommon that ammonia and NOx cause damage to vegetation nearby or humans and animals, however, long-time exposure to NOx may cause “impaired pulmonary functions in humans” according to the text. 

Hydrocarbon and Volatile Organic Compound Pollutants- Hydrocarbons, as outlined in the book “are a diverse group of chemicals whose molecular structures containing various combinations of hydrogen and carbon atoms”. Hydrocarbons that are larger in weight are deemed to have a more complex structure that includes liquids, solids, or gasses. Volatile organic compounds can include oxygen or nitrogen or other light elements. Small amounts of methane, the simplest hydrocarbon, are often “out-gassed” by fossil fuels or wildfires and the gases that leave some animals. Methane emissions are around 1.6 billion tonnes globally and natural emissions of methane are around 0.3 billion tonnes yearly. Large amounts of natural emissions of non-methane hydrocarbons are gases that evaporate from vegetation during hot days. Methane is a greenhouse gas that is associated with global warming.

Comparison of Current AQI

Air Quality Index, or AQI, is a tool that is used for reporting how clean or polluted the air is daily. The AQI also outlines the health effects you could have by breathing in polluted air. The AQI uses a scale from 0-500 and as the number increases, the higher the air is polluted. 

	Time of Day	AQI Current	AQI Forecast	PM2.5	O3
Athens, GA (highest)	11:00 pm	140	Unhealthy for Sensitive Groups	52	31
San Antonio, TX (Where I Live)	9:00 pm	70	Moderate	70	29
Los Angeles, CA	7:00 pm	38	43	27	38

In the table above I used the EPA’s Air Now AQI to gather the current highest AQI, the current AQI where I live, and current AQI information from Las Vegas. The time of day that I picked to find the AQI was important because it correlates with why the numbers are on the lower end of the scale. Due to the lack of activity outside that could result in gases emitted into the air, the results show that the air quality in Los Angeles was good. The current highest AQI was in Athens which could be viewed as low considering the time was late at night. 

Lastly, I live in San Antonio where the air quality was moderate but safe to participate in outdoor activities. 

Comparison of Current PM2.5 and O3 to EPA Standards

PM stands for particulate matter, particles in the air, and pm is the air pollution you can see. Particulate matter that is 2.5 microns or fewer is only visible when it is concentrated in the air and because of how light the particles create health hazards due to their ability to stay in the air longer. This is a damaging air pollutant because of how tiny the particulate matter helps it enter our bodies through our noses that could lead to compromising the lungs or even the circularity system. 

Ground-level ozone, or O3, is a very dangerous air pollutant. The pollution from ground-level ozone can come from power/chemical plants, cars, etc. Ozone can cause major damage to wild vegetation and agriculture and harm humans and other animals sensitive to Ozone. It was stated in the book that the toxicity of ozone can irritate membranes in the eyes and cause respiratory and lung problems.

National Standard	San Antonio Current measured over 1 hour	Time of Day
PM2.5  Average measured over 24 hours - 35 μg/m3	6.0 µg/m3	11:00 am
O3  Average measured over 8 hours - 70 ppb (137 µg/m3)	33 ppb	11:00 am

Above is a table that consists of data that I summarized using the Texas Commission on Environmental Quality.

References

 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/index.cfm?action=aqibasics.aqi

Texas Commission on Environmental Quality.” Go to TCEQ Web Page, https://www.tceq.texas.gov/cgi-bin/compliance/monops/select_curlev.pl. 

Texas Commission on Environmental Quality.” Texas Commission on Environmental Quality, https://www.tceq.texas.gov/cgi-bin/compliance/monops/select_curlev.pl?user_param=88502.