Car Emissions: A hidden health threat in cities

Automobile exhaust emission has become the main source of air pollution in modern cities, and its harm is far more than the public cognition. These seemingly harmless exhaust gases actually contain hundreds of harmful substances, posing a serious threat to the environment and human health.
The main pollutants in exhaust gas include carbon monoxide, nitrogen oxides, hydrocarbons and particulate matter. These substances will produce photochemical smog under the action of sunlight, leading to the deterioration of urban air quality. Data show that more than 70% of harmful substances in urban air come from vehicle exhaust emissions, of which PM2.5 contributes more than 30%.
The impact on human health is particularly serious. Long-term exposure to exhaust gas will lead to a significant increase in the incidence of respiratory diseases and cardiovascular diseases. Studies have shown that residents living near major roads have a 20 percent higher incidence of lung cancer than in general areas. Children are more vulnerable, and lead in exhaust fumes can affect intellectual development and lead to reduced learning ability.
The environmental damage is also staggering. Nitrogen oxides in exhaust gas are the main cause of acid rain, resulting in soil acidification and vegetation destruction. Carbon dioxide emissions aggravate the greenhouse effect, and the problem of global warming is becoming increasingly serious. Urban heat island effect is closely related to exhaust emissions, forming a vicious circle.
It is urgent to control automobile exhaust pollution. It is necessary to improve fuel standards, promote new energy vehicles, and improve public transportation. Only by adopting systematic control measures can we effectively curb exhaust pollution and protect public health and environmental safety.