The graph below shows how vehicle type and speed affect nitrogen oxide emissions.

Practice this IELTS Writing Task 1 question on IELTSX. The graph below shows how vehicle type and speed affect nitrogen oxide emissions.

How vehicle type and speed affect nitrogen oxide emissions - IELTS Writing Task 1

You should spend about 20 minutes on this task.

Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

Write at least 150 words.

IELTS Writing Task 1 chart for How vehicle type and speed affect nitrogen oxide emissions
Chart supplied with the IELTS Writing Task 1 question: How vehicle type and speed affect nitrogen oxide emissions

A student's answer to this task, and the feedback on it

Written by an IELTSX user under exam conditions and published unedited and anonymously. Band 7 ยท 189 words.

The line chart illustrates the effect of the type of the vehicle and its speed on nitrogen oxide emissions.

Overall, lorries and buses emit significantly more nitrogen oxide into the atmosphere compared to cars. Moreover, it seems that relatively more emissions are released at 20 and over 120 kph than other speeds in all four modes of transportation. This is particularly pronounced in lorries and buses, whereas the disparity is not huge in petrol and diesel powered cars.

Focusing on the largest figures in the graph, buses produce 40g/km nitrogen oxide emissions at 20kph and even higher levels at speeds of 120+ kph. Similarly, lorries emit approximately 32 and 28 g/km at these respective speeds. In any other speed, however, this number is notably low, especially at 60 and 80 kph with buses fall to its low of 28 and lorries at 21.

In contrast, the figures for petrol and diesel cars range between roughly 9 to 13 g/km and 5 to 7 g/km, respectively. The gaps between lows and highs they report are quite similar to those of buses and lorries albeit they record a much steady trajectory.

Examiner feedback

This is a strong response that clearly identifies the main trends and provides sufficient data support. To reach a higher band, the writer should focus on eliminating minor grammatical inaccuracies and refining the description of the 'U-shaped' curve present in the data.

Task Achievement - 7

- The response covers all requirements of the task, including a clear overview and highlighting key features. - Data is used to support the description, though the interpretation of the "120+ kph" trend for buses/lorries is slightly simplified. - Categorization of vehicles (large vs. small) is effective for comparisons.

Coherence & Cohesion - 7

- Paragraphing is logical and helps to separate the overview from the specific data analysis. - Cohesive devices like "Moreover", "Similarly", and "In contrast" are used effectively to signal transitions. - Sequencing of ideas follows a clear progression from general trends to specific vehicle comparisons.

Lexical Resource - 7

- Uses a good range of vocabulary related to the task, such as "disparity", "pronounced", and "steady trajectory". - Word choice is mostly appropriate, though "report" and "record" are slightly overused in place of simpler descriptive verbs. - Spelling is accurate and word formation is generally correct.

Grammatical Range & Accuracy - 7

- A variety of complex structures is attempted, such as "whereas the disparity is not huge" and "with buses fall to its low". - There are some minor grammatical slips, such as "at any other speed" (should be speeds) and "buses fall" (should be falling). - Punctuation and sentence boundaries are generally well-managed throughout the response.

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