6.3: Photochemical Smog

primary pollutants

emitted directly from a process/source

secondary pollutants

formed when primary pollutants undergo reactions

tropospheric ozone

formed when oxides from fossil fuel combustion react with oxygen in the air in presence of sunlight

effects of increased tropospheric ozone

irritates eyes

creates respiratory illnesses; chest pain and coughing

damages plants → decreases productivity of plants and growth; hinders rate of photosynthesis

photochemical smog

mixture of primary and secondary pollutants formed under the influence of sunlight; ozone is the main pollutant

what factors affect the occurrence of photochemical smog

local topography

population density

use of fossil fuels

the effects of topography and temperature inversions

thermal inversions trap smog in valleys and basins → cool air is trapped beneath a layer of less dense, warm air due to the lack of air movement

what effect does topography have on pollution?

pollution is amplified as air pollutants build up near the ground rather than dissipated by normal air movements

pollution management strategies

altering human activity:

using public transport

using more renewable energies; reducing fossil fuel use

park-and-ride schemes to prevent n.o of cars in urban areas

regulating and reducing pollutants at the point of emission:

using catalytic converters to clean exhaust of primary pollutants from car exhausts

legislation and taxation

clean-up and restoration:

reforestation, re-greening cities