PM2.5 at Different Latitudes

By: Payne Brower

Question

Are different latitudes the cause of varying

concentrations of PM2.5 particles?

Background Information1. Particulate Matter

a. The term used for solid and liquid particles found in the air.

i. Some particles are large enough to be seen with the naked eye.

ii. There are different types of these particles such as PM10 and PM2.5.

b. Particles can be made up of hundreds of different chemicals

i. Some are emitted directly from a source1. Construction sites2. Unpaved roads3. Fields4. Smokestacks5. Fire

ii. Most form in the atmosphere because of complex chemical reactions between chemicals like sulfur dioxide and nitrogen oxide which are emitted from

1. Power plants2. Industries3. Automobiles

1. PM2.5a. Fine inhalable particlesb. Diameter of 2.5 micrometers or smallerc. About 30 times smaller than the width of a haird. Exposure to these particles can affect your lungs and heart.

They can causei. Premature death to people with heart or lung

diseaseii. Nonfatal heart attacksiii. Irregular heartbeativ. Aggravated asthmav. Decreased lung function

vi. Irritation of the airwaysvii. Coughingviii. Difficulty breathing

e. Wind carries these particles long distances and then settle them on ground or water. They can cause

i. Lakes and streams become acidicii. Change in the nutrient balance in coastal waters

and large river basinsiii. Depletion of the nutrients in the soiliv. Damage to sensitive forests and farm cropsv. Effects on the diversity of ecosystems

vi. Stains and damages to stones and other materials

Hypothesis

There will be a correlation between PM2.5 and latitude. If all the variables stay the same except a change in latitude, then PM2.5 levels should be higher the closer the city is to the equator. As you get close to the equator, the average temperature gets hotter because the Sun’s rays are more direct. Temperature affects the formation of PM2.5. Higher temperatures will boost the reactions between sulfates, nitrates, ammonium, and organic carbon, which make up 30-90 percent of all PM2.5 particles.

Procedure1. I selected four cities to measure the PM2.5 levels.

2. I found the coordinates, population, and elevation of each city and made sure

it was similar to the other sample cities.

3. I recorded the PM2.5 of each city at 8:00 pm for 30 days.

4. I entered all my data into an excel spreadsheet and found the average PM2.5

for each city.

5. I divided the micrograms of PM2.5 per cubic meter in each city by the

population of the city to get the PM2.5 levels per capita.

Materials● Wynd Air Quality Tracker● Computer

Website and App

City Latitude Longitude Elevation (ft) Population

Butte, MT 46.0038 -112.5348 5,538 33,964

Farmington, NM 36.7281 -108.2187 5,394 44,067

Windsor, CO 40.4775 -104.9014 4,797 26,806

Big Bear City, CA 34.2611 -116.845 6,772 34,109

Butte, MT

Farmington, NM

Windsor, CO

Big Bear City, CA

Cities

Results

City

Avg.

PM2.5

Avg. PM2.5

Per Capita

Butte, MT 4.41 1.30E-04

Farmington,

NM 4.64 1.05E-04

Windsor, CO 10.11 3.77E-04

Big Bear City,

CA 4.33 1.27E-04

Analysis

According to the data, the amount of PM2.5 per cubic meter in each city was approximately the same, at about 0.0001 to 0.00013 (1.0*10^-4 to 1.3*10^-4) micrograms per cubic meter per person, except for Windsor, which had a much higher average PM2.5 at .000377 (3.77*10^-4) micrograms per cubic meter per person. However, Windsor CO had a few outliers in its data. For five days, there was an unexpectedly high amount of PM2.5 in the air. Upon investigation, I found there was a large fire a little more than 15 miles away from Windsor. Wind could have easily blown smoke from this fire to Windsor, polluting the air for a few days. Wildfires and wind could have caused other smaller outliers later in the data.

If you take out the five largest outliers and find the average of the resulting data, Windsor has a much lower .000192 (1.92*10^-4) micrograms of PM2.5 per cubic meter per person. It still has a higher concentration of PM2.5 than other cities, but that corresponds with the fact that fires were occurring near Windsor. Windsor will still get some of the smoke from nearby fires, which will increase the PM2.5, though less dramatically.

ConclusionMy hypothesis was incorrect. I assumed that there would be a sizable difference in the

amount of PM2.5 at different latitudes. Unexpectedly, the PM2.5 levels of each city of corresponding population and elevation were similar, except in Windsor, CO, where data was possibly affected by nearby wildfires. Latitude did not affect the concentration of PM2.5 because the changes in the climate weren't significant enough to affect PM2.5.

There were a few challenges and limitations in my project. One example was the similarities of the cities. It was difficult to find cities with the same elevation, the same population, similar longitude, and a different enough latitude. My project was not entirely accurate because of slight differences in these variables. However, it is almost impossible to be perfectly accurate because there are no four cities with the same population, longitude, and elevation.

Conclusion cont.Another problem I ran into was measuring the PM2.5 of the cities. I wasn't able to travel

to each city every day to measure the air quality. I used an app from Wynd and a website from IQAir to record the PM2.5 measurements in each city. I found some similar cities that could have worked for my project, but the PM2.5 levels weren't available on the app or the website.

I learned about the creation of PM2.5, its effects on the environment and people, and how it's measured. I became more familiar with Excel, its features, and how it can be helpful in scientific analysis. I had only ever done experiments in physics, so it was definitely out of my comfort zone to experiment in environmental science. It was a fun and enjoyable challenge and I think it is an important subject for us to learn about to help preserve the future of our planet.

Bibliography“Big Bear City Air Quality Index (AQI) and California Air Pollution: AirVisual.” Big Bear City Air Quality Index (AQI) and California Air Pollution | AirVisual, IQAir, www.iqair.com/us/usa/california/big-bear-city.

“Butte Air Quality Index (AQI) and Montana Air Pollution: AirVisual.” Butte Air Quality Index (AQI) and Montana Air Pollution | AirVisual, IQAir, www.iqair.com/us/usa/montana/butte.

“Farmington Air Quality Index (AQI) and New Mexico Air Pollution: AirVisual.” Farmington Air Quality Index (AQI) and New Mexico Air Pollution | AirVisual, IQAir, www.iqair.com/us/usa/new-mexico/farmington.

“Particulate Matter (PM) Basics.” EPA, Environmental Protection Agency, 1 Oct. 2020, www.epa.gov/pm-pollution/particulate-matter-pm-basics.

“Particulate Matter (PM2.5) Trends.” EPA, Environmental Protection Agency, 8 June 2020, www.epa.gov/air-trends/particulate-matter-pm25-trends.

Wang, Jianhua, et al. “Figure 4. The Relationship between PM2.5 and Temperature over Four...” ResearchGate, 14 Oct. 2020, www.researchgate.net/figure/The-relationship-between-PM25-and-temperature-over-four-seasons-The-straight-lines-are_fig3_280911119.

“Windsor Air Quality Index (AQI) and Colorado Air Pollution: AirVisual.” Windsor Air Quality Index (AQI) and Colorado Air Pollution | AirVisual, IQAir, www.iqair.com/us/usa/colorado/windsor.

“Wynd.” Wynd Technologies, Inc., Apr 21, 2017. Vers. 1.00.209. Google Play Store, https://play.google.com/store/apps/details?id=com.hellowynd.wynd.