Photochemical smog forms from sunlight reacting with nitrogen oxides and hydrocarbons.
Practise Biochemistry, Environment & Industry All Biochemistry, Environment & Industry topics
Smog is air pollution that reduces visibility and harms health. Photochemical smog forms when sunlight drives reactions between nitrogen oxides and volatile organic compounds from vehicles and industry, producing ground-level ozone, peroxyacyl nitrates and aerosols. Classical smog, sometimes called London smog, is a mixture of smoke, sulfur dioxide and fog produced by coal burning. Both types irritate the airways, aggravate asthma and increase cardiovascular risk. Mitigation includes vehicle emission controls, catalytic converters and reduced use of solvents.
Key ideas: Photochemical smog (Los Angeles type): NOx plus volatile organic compounds plus sunlight form ozone, PAN and aldehydes; NO2 plus light gives NO plus O, and O plus O2 gives O3. Classic smog (London type) is cold, humid and made of SO2 and soot from coal. Peaks in sunny afternoon traffic conditions.
Common mistakes and connections: Mistake: thinking all smog is the same or that ozone is emitted directly. Temperature inversions trap pollutants. Catalytic converters reduce NOx, CO and hydrocarbons. Links to nitrogen oxides, acid rain (SO2 to H2SO4) and the air quality index.
Typical ground-level ozone in photochemical smog peaks in the afternoon as sunlight drives reactions between nitrogen oxides and volatile organic compounds. The interactive lesson shows this as a live animation or chart.
Los Angeles and Delhi have experienced severe smog episodes during calm, sunny weather.
Photochemical smog forms from sunlight reacting with nitrogen oxides and hydrocarbons.
Smog is a beginner topic in Biochemistry, Environment & Industry. It needs no earlier chemistry lessons and is a good starting point.
Study these earlier topics in Biochemistry, Environment & Industry first: Carbon Cycle, Ozone Layer Depletion, CFCs.
The next topics in Biochemistry, Environment & Industry are Particulate Matter and Air Quality Index.
Yes. The interactive lesson includes a self-check question on Smog, and the Biochemistry, Environment & Industry quiz draws on every topic in this area.
Smog is topic 76 of 127 in Biochemistry, Environment & Industry.
Browse all 127 topics in Biochemistry, Environment & Industry