IB ESS HL 8.3.3 Fossil Fuel Combustion Questions

primary pollutant is one which is active on emission / directly impacts the environment;
eg $\mathrm{CO}_{2}$ is released from burning fossil fuels and actively contributes to global warming / CFCs are released from aerosols and actively contribute to ozone depletion;
a secondary pollutant is one formed from a primary pollutant through physical/chemical change;
eg $\mathrm{CO}_{2}$ combines with sea water to form carbonic acid that leads to impacts on calciferous shelled organisms or corals / $\mathrm{NO}_{\mathrm{x}}$ combines with water to form acid precipitation / $\mathrm{NO}_{2}$ forms PAN/ozone (that contributes to photochemical smog);

Marking guidance:

Award [2 max] if no examples are given.
Examples of primary pollutants need to include their direct impact (eg $\mathrm{NO}_{x}$ can be either primary or secondary without such specification) and examples of secondary need to include the process leading to their pollutionary impact).
Award [1 max] for example of primary, and [1 max] for example of secondary.