Eironmental Chemistry-Air Flashcards
(16 cards)
What are three natural factors that influence air quality?
Wind patterns, temperature inversions, and volcanic eruptions.
How do human activities degrade air quality?
Fossil fuel combustion (vehicles, industries), agricultural emissions (NH₃), and deforestation.
Why do temperature inversions worsen air pollution?
They trap pollutants near the ground by preventing vertical air mixing.
What is the role of sunlight in smog formation?
Sunlight breaks NO₂ into NO and atomic oxygen (O), initiating ozone production.
Write the reaction for ground-level ozone (O₃) formation.
NO₂ absorbs sunlight (UV) → splits into NO + O
O + O₂ → O₃ (ground-level ozone)
How do VOCs and NOₓ interact to form PANs?
VOCs + NOₓ → PANs (e.g., CH₃COOONO₂) + Aldehydes
VOCs (like aldehydes) react with NO₂ in the presence of sunlight (UV) to form PANs (Peroxyacyl Nitrates) — toxic components of photochemical smog ☠️☀️
What is the primary source of NOₓ in urban areas?
Vehicle exhaust and industrial combustion.
How does SO₂ contribute to acid rain?
2SO₂ + O₂ + H₂O → H₂SO₄ (Sulfuric acid)
HSO₄⁻ + H₂O → H₃O⁺ + SO₄²⁻ (lowers the pH of rainwater making it acidic,)
What reaction converts NO₂ to nitric acid (HNO₃)?
2 NO₂ + H₂O → HNO₂ + HNO₃
Then HNO₂ oxidizes to form more HNO₃ (nitric acid)
Why is coal combustion a major cause of acid rain?
Coal contains sulfur, which oxidizes to SO₂ during burning.
Why does ground-level ozone (O₃) form in cities but not naturally?
Requires high NOₓ + VOCs (from vehicles) + sunlight—rare in pristine areas.
How does deforestation indirectly affect air quality?
Reduces CO₂ absorption (worsening greenhouse effect) and increases particulate matter.
Why are VOCs problematic even if non-toxic?
They react with NOₓ to form ozone/PANs, amplifying smog.
🧠 Q: How is photochemical smog formed?
Study Bro
Your Aim is right, now hold the bow accurately
🔄 Process:
NO₂ absorbs sunlight (UV) → splits into NO + O
O + O₂ → O₃ (ground-level ozone)
Ozone + hydrocarbons + NOx → PANs & free radicals
These chemicals together = photochemical smog ☠️
What are PANs in photochemical smog?
✅ A:
PANs (Peroxyacyl Nitrates) are toxic secondary pollutants formed when hydrocarbons react with NO₂ in sunlight ☀️
🔹 Cause eye irritation, breathing issues, and damage to plants
🔹 Major component of photochemical smog ☠️
🧠 Q: How does photochemical smog affect aesthetics of the environment?
Photochemical smog creates a brownish haze in the air, which:
🔹 Reduces visibility 🌫️
🔹 Makes the sky look dull or dirty ☁️
🔹 Stains buildings and monuments 🏛️
🔹 Ruins scenic beauty of cities & nature 🌄😭
