chemistry open book paper (2003)
Open book paper In terms of the production of photochemical smog, primary pollutants are the pollutants released directly into the atmosphere by, for example combustion of fuels in cars and power stations. The primary pollutants produced as a result of motor vehicles are oxides of nitrogen (NO and NO2) called NOx, carbon monoxide (CO), and hydrocarbons (CxHy). Secondary pollutants are formed as a result of chemical reactions that take place when sunlight shines on a mixture of two of the primary pollutants. The secondary pollutants are ozone (O3), which is a major component of photochemical smog, NO2, hydrogen peroxide (H2O2), peroxyacetyl nitrate (PAN) and partially oxidised hydrocarbons (HNO3). The three main inputs in a coal-fired power station are coal, cooling water and very pure water. The main outputs are waste heat, CO2, SOx, NOx, ash and electricity. The only primary pollutants being produced in this case are the nitrogen oxides (NOx).