Calculate the percentage by which the mean PM$_{2.5}$ concentration was lower in the park than at the roadside station.

Describe two differences between air pollution at the roadside and in the park.

Explain why exposure to PM$_{2.5}$ may present a greater respiratory risk than exposure to larger particles.

Evaluate which two proposed measures should be prioritized to reduce exposure to air pollution on Central Avenue.

Calculate the increase in mean lichen cover between 0 m and 200 m from the road.

Describe the relationship between distance from the road, PM$_{2.5}$ concentration and lichen cover.

Explain how lichens may be used as an indicator of urban air pollution in this investigation.

Evaluate the conclusion that traffic pollution caused the observed change in lichen cover.

Identify the time of maximum tropospheric ozone concentration.

Determine the time lag between the maximum $NO_2$ concentration and the maximum ozone concentration.

Explain the diurnal pattern of pollutants shown in Figure 5.

Explain two ways in which acid deposition may cause a decline in a freshwater fish population.

Explain the formation of tropospheric ozone as a component of photochemical smog.

Describe the temperature structure during the inversion shown in Figure 1.

Explain how the inversion and the urban basin can intensify photochemical smog.

Explain why the indirect impacts of tropospheric ozone may be greater in this neighbourhood than in a wealthier neighbourhood.

Outline four links between anthropogenic activities and primary air pollutants in urban areas.

Explain how a combination of transport, regulatory and green-infrastructure interventions can reduce urban air pollution.

Using named real-world examples, evaluate the effectiveness of transport-centred strategies compared with technological and green-infrastructure strategies for managing urban air pollution.

Calculate the time lag between the morning maximum in nitrogen monoxide and the maximum in tropospheric ozone.

Explain the difference in timing between these two maxima.

Calculate the decrease in median daily maximum ozone concentration.

Interpret the result of the Mann–Whitney test.

Outline two reasons why these results do not prove that the low-emission zone caused the decrease.

Calculate the ratio of the $PM_{2.5}$ concentration at the basin centre during inversion conditions to that during normal conditions.

Compare the spatial patterns of $PM_{2.5}$ and tropospheric ozone during the temperature inversion.

Explain why the temperature inversion and basin topography produce high pollutant concentrations near the basin floor.

Evaluate strategies that Valle Gris could use to reduce exposure during future inversion events.

Calculate the percentage by which respiratory clinic visits in Riverside exceeded those in Hillside.

Analyse the relationship between ozone exposure, income and the two health-related indicators across the three districts.

Explain how direct ozone damage may lead to indirect economic costs.

Evaluate how the city should respond to the unequal distribution of ozone impacts.

Explain the atmospheric formation of nitric acid and sulfuric acid from nitrogen oxides and sulfur dioxide.

Explain how acid deposition can affect terrestrial ecosystems, freshwater ecosystems, human health and buildings.

Using named real-world examples, evaluate strategies implemented before emissions occur, at the point of release, and after deposition or damage to reduce the environmental impacts of sulfur dioxide and nitrogen oxides.

Distinguish between $PM_{2.5}$ and $PM_{10}$ and explain why particle size affects respiratory risk.

Analyse how the activities described could produce different urban air pollutants and how these pollutants could be reduced.

Using named real-world examples, discuss whether strict air-quality regulation can be achieved without increasing social inequality or limiting urban economic development.

Calculate the percentage decrease in annual mean tropospheric ozone concentration in Northgate between 2016 and 2024.

Using 2020 as the reference year, compare changes in the three pollutants from 2020 to 2024 in Northgate and Eastbank.

Explain why reducing both nitrogen oxides and VOC emissions may reduce photochemical smog.

Evaluate the conclusion that Northgate's policies caused the observed decrease in tropospheric ozone.

Explain the formation of tropospheric ozone and peroxyacyl nitrates as components of photochemical smog.

Analyse why the highest concentrations of secondary pollutants may occur later in the day and downwind from the largest primary-emission sources.

Using named real-world examples, evaluate strategies for reducing photochemical smog in a warm, car-dependent city.

Explain how a temperature inversion suppresses the vertical dispersion of urban air pollutants.

Analyse how the atmospheric conditions and urban form described could interact to intensify photochemical smog.

Using named real-world examples, evaluate whether changes to urban design are more effective than emergency responses for reducing the impacts of photochemical-smog episodes.

Distinguish between direct biological, direct physical and indirect impacts of tropospheric ozone, giving one example of each.

Explain how direct exposure to tropospheric ozone can produce indirect costs that are distributed unequally across an urban population.

Using named real-world examples, to what extent can policies that reduce average urban ozone concentration also achieve environmental justice?