Atmospheric Pollution & Landfill Gas: Air Quality Analysis

Atmospheric Pollution: Landfill Gas and Air Quality

Introduction to Atmospheric Pollution

  • Definition: Atmospheric pollution refers to the contamination of the air by various pollutants.

  • Types of Pollutants:

    • Gaseous pollutants: Examples include carbon dioxide CO₂, methane CH₄, and hydrogen sulfide H₂S.

    • Particulate Matter: Includes particulate matter with a diameter of 2.5 micrometers or less (PM2.5) and particulate matter with a diameter of 10 micrometers or less (PM10).

  • Why It Matters:

    • Health Effects: Air pollution can cause respiratory and cardiovascular problems.

    • Environmental Degradation: It contributes to acid rain, smog, and ecosystem damage.

    • Climate Impact: Certain pollutants, like methane, are potent greenhouse gases.

Landfill Gas (LFG)

  • What It Is: Landfill gas is produced from the anaerobic decomposition of organic waste in landfills.

  • Major Components:

    • Methane (CH₄): Typically makes up approximately 50-60% of landfill gas.

    • Carbon Dioxide (CO₂): Generally comprises about 30-40% of LFG.

    • Trace gases: Smaller amounts of gases like hydrogen sulfide (H₂S) and non-methane volatile organic compounds (NMVOCs) are also present.

  • Emissions Pathways: LFG can escape through the soil, gas vents, or leaks in the landfill infrastructure.

Impacts of Landfill Gas on Air Quality

  • Local Air Quality:

    • Methane (CH₄) contributes to the formation of ground-level ozone (O₃), which is a respiratory irritant.

    • Hydrogen sulfide (H₂S) causes odor issues and can irritate the eyes and respiratory system.

  • Greenhouse Gas Effect:

    • Methane (CH₄) has a global warming potential 25 times higher than carbon dioxide (CO₂).

  • Hazards: Landfill gas can pose explosion risks and lead to respiratory problems. It can also impact atmospheric chemistry.

Monitoring and Measurement Instruments

  • Gas chromatography: Used for measuring the concentrations of methane (CH₄) and carbon dioxide (CO₂).

  • Electrochemical sensors: Employed for detecting hydrogen sulfide (H₂S).

  • Portable AQ monitors: Utilized for monitoring particulate matter (PM) and ozone.

  • Sampling Locations: Monitoring is conducted on-site, downwind, and at the perimeter of the landfill.

Air Quality Indices (AQI) Overview

  • What is AQI?: The Air Quality Index (AQI) is a scale used to report daily air quality.

  • Main Pollutants Considered: Particulate matter (PM2.5 and PM10), ozone (O₃), carbon monoxide (CO), sulfur dioxide (SO₂), and nitrogen dioxide (NO₂).

  • Scale:

    • The AQI scale ranges from 0 to 500.

    • 0-50: Good

    • 51-100: Moderate

    • 101-150: Unhealthy for sensitive groups

Calculating AQI - Example

  • Formula for AQI (per pollutant):

    AQI = \frac{I{high} - I{low}}{C{high} - C{low}} \times (C - C{low}) + I{low}

    Where:

    • C = pollutant concentration

    • C{low}, C{high} = breakpoints around C

    • I{low}, I{high} = corresponding AQI values

  • Example: If the measured concentration of PM2.5 is 55 µg/m³, the AQI is approximately 150, which falls into the "Unhealthy for sensitive groups" category.

AQI Calculation Examples

Pollutant: PM2.5 (Particulate Matter < 2.5 micrometers)

  • Measured concentration: C = 55 \, \mu g/m^3

  • Step 1: Use EPA Breakpoints Table for PM2.5

    • Good: 0-50 (AQI), 0.0 - 12.0 (\mu g/m^3

    • Moderate: 51-100 (AQI), 12.1 - 35.4 (\mu g/m^3

    • Unhealthy for Sensitive Groups: 101-150 (AQI), 35.5 - 55.4 (\mu g/m^3

    • Unhealthy: 151-200 (AQI), 55.5 - 150.4 (\mu g/m^3

  • Step 2: Apply the AQI Formula

  • Final AQI: ~148, which is in the “Unhealthy for Sensitive Groups” category.

  • Health Meaning of 148 AQI (PM2.5): People with respiratory or heart disease, older adults, and children should reduce prolonged or heavy exertion. The general public is not likely to be affected at this AQI level.

Pollutant: CO (Carbon Monoxide)

  • Measured concentration: C=9.0 ppm (parts per million)

  • Step 1: Use EPA Breakpoints Table for CO

    • Good: 0-50 (AQI), 0.0 - 4.4 (ppm)

    • Moderate: 51-100 (AQI), 4.5 - 9.4 (ppm)

    • Unhealthy for Sensitive Groups: 101-150 (AQI), 9.5 - 12.4 (ppm)

    • Unhealthy: 151-200 (AQI), 12.5 - 15.4 (ppm)

  • Since 9.0 ppm falls in the Moderate category, we use the breakpoints:

    • C_{low} = 4.5

    • C_{high} = 9.4

    • I_{low} = 51

    • I_{high} = 100

  • Step 2: Use the AQI Formula

  • Final AQI: ~96, which is in the “Moderate” category.

  • Health Meaning of 96 AQI (CO): Acceptable air quality, but some pollutants may be a concern for a very small number of people who are unusually sensitive to air pollution. Sensitive groups (e.g., people with cardiovascular conditions) may experience mild effects.

Pollutant: SO₂ (Sulfur Dioxide)

  • Measured concentration: C = 250 \,\mu g/m^3

  • Step 1: Use EPA Breakpoints Table for 1-hour SO2 (ppb)

    • Good: 0-50 (AQI), 0-35 (ppb)

    • Moderate: 51-100 (AQI), 36-75 (ppb)

    • Unhealthy for Sensitive Groups: 101-150 (AQI), 76-185 (ppb)

    • Unhealthy: 151-200 (AQI), 186-304 (ppb)

  • Our value converted to ppb is 95.4 ppb, it falls into the Unhealthy for Sensitive Groups category.

    • C_{low} = 76

    • C_{high} = 185

    • I_{low} = 101

    • I_{high} = 150

  • Step 2: Apply the AQI Formula

  • Final AQI: ~110, which falls in the "Unhealthy for Sensitive Groups" category.

  • Health Meaning of 110 AQI (SO₂): Sensitive groups (e.g., children, asthmatics, elderly) should limit outdoor exertion. The general population is not likely to be affected at this level.

Conclusion

  • Global AQI = the highest individual AQI value among pollutants

  • Example Recap: Global AQI = Max(148, 96, 110) = 148

  • So, Global AQI = 148, and the main pollutant is PM2.5.

  • Health Advice Based on Global AQI = 148

  • Sensitive groups (children, elderly, people with heart or lung conditions) should limit outdoor exertion. The general population is unlikely to be affected at this level.

Flashcard #1
Term: Atmospheric pollution
Definition: Contamination of the air by various pollutants

Flashcard #2
Term: Gaseous pollutants
Definition: Carbon dioxide CO2CO2​, methane CH4CH4​, and hydrogen sulfide H2SH2​S

Flashcard #3
Term: Particulate Matter
Definition: Particulate matter with a diameter of 2.5 micrometers or less (PM2.5PM2.5) and particulate matter with a diameter of 10 micrometers or less (PM10PM10)

Flashcard #4
Term: Health Effects of Air Pollution
Definition: Respiratory and cardiovascular problems

Flashcard #5
Term: Environmental Degradation due to Air Pollution
Definition: Contributes to acid rain, smog, and ecosystem damage

Flashcard #6
Term: Climate Impact of Air Pollution
Definition: Certain pollutants, like methane, are potent greenhouse gases

Flashcard #7
Term: Landfill Gas (LFG)
Definition: Gas produced from the anaerobic decomposition of organic waste in landfills

Flashcard #8
Term: Methane (CH4CH4​) in LFG
Definition: Typically makes up approximately 50-60% of landfill gas

Flashcard #9
Term: Carbon Dioxide (CO2CO2​) in LFG
Definition: Generally comprises about 30-40% of LFG

Flashcard #10
Term: Trace gases in LFG
Definition: Smaller amounts of gases like hydrogen sulfide (H2SH2​S) and non-methane volatile organic compounds (NMVOCs) are also present

Flashcard #11
Term: Impact of Methane on Local Air Quality
Definition: Methane (CH4CH4) contributes to the formation of ground-level ozone (O3O3), which is a respiratory irritant

Flashcard #12
Term: Impact of Hydrogen sulfide (H2SH2​S) on Local Air Quality
Definition: Causes odor issues and can irritate the eyes and respiratory system

Flashcard #13
Term: Global Warming Potential of Methane (CH4CH4) Definition: Has a global warming potential 25 times higher than carbon dioxide (CO2CO2)

Flashcard #14
Term: Gas chromatography
Definition: Used for measuring the concentrations of methane (CH4CH4) and carbon dioxide (CO2CO2)

Flashcard #15
Term: Electrochemical sensors
Definition: Employed for detecting hydrogen sulfide (H2SH2​S)

Flashcard #16
Term: Portable AQ monitors
Definition: Utilized for monitoring particulate matter (PM) and ozone

Flashcard #17
Term: Air Quality Index (AQI)
Definition: Scale used to report daily air quality

Flashcard #18
Term: Main Pollutants Considered in AQI
Definition: Particulate matter (PM2.5PM2.5 and PM10PM10), ozone (O3O3), carbon monoxide (CO), sulfur dioxide (SO2SO2), and nitrogen dioxide (NO2NO2​)

Flashcard #19
Term: AQI Scale
Definition: Scale ranges from 0 to 500

Flashcard #20
Term: Formula for AQI (per pollutant)
Definition: AQI=Ihigh−IlowChigh−Clow×(C−Clow)+IlowAQI=Chigh−ClowIhigh−Ilow​×(C−Clow)+Ilow