This topic will cover the basics of air quality, including the composition of the atmosphere, factors influencing air quality, and the importance of monitoring air pollution.
Introduction to Air Quality
Key concepts, why it matters, and how it’s measured
| Term | Definition |
|---|---|
| Air Quality | The condition of the air in terms of its composition, concentration of pollutants, and its suitability for human health, ecosystems, and climate. |
| Air Quality Index (AQI) | A standardized scale (usually 0‑500) that translates complex pollutant measurements into a single number that indicates health risk levels. |
| Pollutant | Any substance in the air that can cause adverse effects—e.g., gases, particles, or biological materials. |
| Category | Common Species | Primary Sources | Typical Health/Environmental Impacts |
|---|---|---|---|
| Criteria Gases | • O₃ (ozone) • NO₂ (nitrogen dioxide) • SO₂ (sulfur dioxide) • CO (carbon monoxide) |
• Vehicle exhaust, power plants, industry, biomass burning | • Respiratory irritation, reduced lung function, acid rain (SO₂, NO₂) |
| Particulate Matter (PM) | • PM₁₀ (≤10 µm) • PM₂.₅ (≤2.5 µm) |
• Combustion, construction dust, agricultural activities, wildfires | • Cardiovascular disease, lung inflammation, visibility reduction |
| Volatile Organic Compounds (VOCs) | • Benzene, formaldehyde, toluene | • Solvent use, gasoline vapors, industrial processes | • Eye/nose irritation, some are carcinogenic |
| Heavy Metals | • Lead (Pb), mercury (Hg), arsenic (As) | • Smelting, waste incineration, coal combustion | • Neurological damage (Pb), bioaccumulation in food webs |
| Biological Particles | • Pollen, mold spores, bacteria | • Natural vegetation, indoor environments | • Allergic reactions, asthma triggers |
Human Health
Ecosystem Health
Climate Interaction
Economic Impact
| Technique | What It Measures | Typical Deployment |
|---|---|---|
| Ground‑based stations | Real‑time concentrations of gases, PM, meteorology | Urban networks, regulatory sites |
| Passive samplers | Integrated (e.g., 1‑week) averages of gases | Low‑cost, community monitoring |
| Remote sensing (satellite) | Column densities of NO₂, SO₂, aerosol optical depth | Large‑scale, regional trends |
| Mobile platforms (cars, drones, backpacks) | High spatial resolution of pollutants | Hot‑spot investigations |
| Low‑cost sensors (electrochemical, optical) | Approximate concentrations of CO, O₃, PM₂.₅ | Citizen |