A major survey could highlight air pollution on a busy road.
The Islington Green Party and Mapping for Change installed 30 diffusion tubes, which collect nitrogen dioxide (NO2), on buildings between Highbury and Finsbury Park, along Blackstock Road.
The irritant gas, which is created in vehicle combustion, can cause difficulty breathing in high concentrations.
This three-week experiment, which finished on Friday, may expose a dangerous amount of NO2 in an area which houses four primary schools and two secondaries.
Experts from University College London (UCL) will examine the tubes and the data will be revealed at a public meeting next month.
Caroline Russell, Islington Green Party spokeswoman, said: “I fear pollution levels on Blackstock Road will be high.
“The levels of asthma and cardio vascular disease in Islington are already well-documented, linked to living and working by roads such as Blackstock which carry more than 10,000 car movements everyday.
Campaigners also monitored dust air pollution by wiping windows between Highbury Grove and Finsbury Park.
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