Name the oxide pollutant with the greatest concentration in 2021.
Name the pollutant whose concentration decreases steadily from 2019 to 2022.
Calculate the mean mass, in ng, of particulates in a 250 cm$^3$ sample of polluted air in 2019.
State one harmful effect on health caused by particulates.
Particulates are produced by the incomplete combustion of hydrocarbons. State what is meant by the term incomplete combustion.
Oxides of nitrogen help cause acid rain. From the list, choose the pH of an acidic solution: pH 5, pH 7, pH 9, pH 13.
Complete the sentence about cutting down oxides of nitrogen from car exhausts by selecting two words from the list: The emission of oxides of nitrogen from car exhausts is reduced by using a ................ ................. .
Oxides of nitrogen may be generated by bacteria acting on nitrates. Name the aqueous solution and the metal used in the nitrate ion test.
Nitrogen dioxide breaks down when heated. Nitric oxide and oxygen are formed. Finish the symbol equation for this reaction: $....\text{NO}_2 \rightleftharpoons 2\text{NO} + ............$
State what the symbol $\rightleftharpoons$ means.