Istanbul Technical University (ITU) Department of Environmental Engineering Faculty member professor Levent Kuzu stated: "The main cause of air pollution in cities is traffic. Besides the number of vehicles, traffic congestion significantly pollutes the air."

Kuzu, speaking to an Anadolu Agency (AA) correspondent as part of "Road Safety and Traffic Week," said that air pollution is caused by human emissions, including industrial activities, residential heating and traffic in cities.

Regarding naturally occurring emissions such as desert dust transport, aerosols emitted from the sea surface, and gases released by vegetation reacting in the atmosphere to form fine particles, Kuzu emphasized: "They all share the common need for energy. Energy needs are mostly met by burning various fossil fuels, which results in the release of pollutants and particles that contribute to air pollution during combustion."

Pollution ups health care costs

Kuzu emphasized the direct negative impact of air pollutants on human health, noting that an average person breathes about 15 cubic meters of air daily. He said, "Therefore, exposure to pollutants occurs through the respiratory system, with the most significant effects observed on the respiratory system."

Kuzu also highlighted the economic effects of air pollution: "Increased health care costs result from deteriorating health, along with potential loss of productivity. Air pollution can also cause various effects on materials, such as deformation and corrosion, leading to shortened lifespan of materials. Additionally, air pollution affects vegetation."

Kuzu pointed out that before the use of natural gas in Istanbul, there was a serious air pollution problem. He mentioned that certain parameters, especially sulfur dioxide, were more than 10 times higher in the air in the early 1990s than the current average values. He also stated that with the gradual transition to natural gas consumption for residential heating, the contribution of domestic heating to air pollution in city centers has significantly decreased.

Kuzu explained that to see the impact of traffic-related air pollution, one could compare it with the COVID-19 lockdown period. He stated:

"Although comparing short-term measurements with long-term values may not be accurate due to meteorological differences, it can be considered an indicator. PM10 concentrations in Istanbul's Beşiktaş district – during the full lockdown in April 2020 – were measured at an average of 15 micrograms per cubic meter. During this period, human-related emissions were nearly zero, and the measured emissions were mostly natural. At the same station, the annual average PM10 concentrations measured since 2021 range from 32 to 38 micrograms per cubic meter."

Traffic causes city air pollution

Kuzu mentioned that there are approximately 5.4 million registered vehicles in traffic in Istanbul, and due to the high-rise nature of settlements, there is a high density of vehicles per unit area. He said: "Additionally, human mobility is generally intense during commute hours, leading to increased exposure to air pollutants due to traffic congestion."

Kuzu emphasized the avoidance of diesel vehicles in Europe, stating: "While gasoline combustion generates particles of 20-40 nanometers, diesel emissions create particles of 60-120 nanometers. Unlike gasoline vehicles, diesel cars attempt to capture these particles with diesel particulate filters. Reducing the use of diesel vehicles will contribute to preserving air quality."

He also expressed that traffic is now one of the primary causes of air pollution, continuing: "The main cause of air pollution in cities is traffic; besides the sheer number of vehicles, traffic congestion significantly pollutes the air as it consumes more fuel than necessary, leading to air pollution and economic loss, dense emissions on congested streets between buildings due to vertical construction makes it difficult for pollutants to disperse, resulting in higher exposure for individuals on these streets."

He continued, "Therefore, traffic emissions are the main source of human-induced air pollution in city centers today. Alternatives such as public transportation can help reduce per capita emissions. Additionally, using solutions like electric bicycles and scooters for short-distance trips, known as micromobility, can also contribute significantly to reducing air pollution."

Kuzu mentioned that exhaust emissions do not occur with rail systems and electric vehicles, which could help reduce air pollution within cities.

'EV numbers will rise'

Kuzu emphasized that when it comes to pollutants from vehicles, exhaust emissions are the first thing that comes to mind, but in addition to exhaust, particles from both tires and roads are released into the air due to friction from brake pads and tire wear.

"Additionally, various volatile organic compounds escape into the air during fuel filling at gas stations. The number of electric vehicles is expected to increase in the future. Therefore, exhaust-related air pollutant emissions will decrease in densely populated urban centers, but emissions from the other sources I mentioned will continue to be released into the atmosphere," he explained.