Q.What are the harmful effects of photochemical smog and how can they be controlled?

Harmful effects of photochemical smog:

• On humans: irritation of the eyes (redness, watering), irritation of the nose and throat, headache, chest pain/tightness, breathing difficulty, aggravation of asthma and bronchitis, and reduced resistance to lung infections.
• On plants: ozone and PAN damage plant tissue, causing bleaching or mottled/yellowed (chlorotic) leaves, premature leaf fall and reduced growth.
• On materials: ozone in particular attacks rubber, causing it to crack; painted surfaces and fabrics can also be damaged.
• General: reduced visibility due to the haze created by the oxidants.

Control measures:

• Fitting catalytic converters in automobile exhaust systems, which convert unburnt hydrocarbons and CO to CO2/H2O and NOx to N2/O2 before they are released, cutting off the raw materials for smog formation.
• Using cleaner-burning or alternative fuels and better engine designs to reduce hydrocarbon and NOx emissions.
• Restricting vehicular traffic and encouraging public transport in city centres. …

Split the answer into two clear parts — effects (on humans, plants, materials) and control (source reduction via catalytic converters/cleaner fuel, plus mi …

• Giving only generic 'plant more trees' advice without naming the specific species mentioned in the textbook.
• Mixing up effects of photochemical smog with those of classical (SO2) smog. …