What is a primary strategy for improving air quality in cities?

Encouraging the use of public transportation is a primary strategy for improving air quality in cities because it significantly reduces the number of individual vehicles on the road. High traffic volumes contribute to air pollution as vehicles emit harmful pollutants, including nitrogen oxides, carbon monoxide, and particulate matter. By promoting public transit options, such as buses, trains, and subways, cities can decrease overall vehicle emissions, lower congestion, and improve air quality.

Public transportation systems are generally more efficient in terms of fuel consumption per passenger compared to single-occupancy vehicles. When more people utilize public transit, the collective impact results in fewer pollutants being released into the atmosphere. This not only improves air quality but also enhances public health by reducing respiratory diseases and other pollution-related health issues in urban populations.

Other strategies, like limiting gasoline usage, can also contribute to air quality improvements, but their effectiveness may depend on broader systemic changes, such as the availability of alternative fuels and vehicle technologies. Reducing vegetation is counterproductive, as plants play a crucial role in filtering air pollutants. Expanding highways may initially provide relief from congestion but typically leads to increased vehicle traffic and, consequently, higher levels of air pollution in the long term.