Final answer:
The issue that is not caused by NOx emissions is addiction. NOx contributes to acid rain, photochemical smog, and can cause eye irritation, but it is not associated with addiction.
Step-by-step explanation:
Among the options provided, the one that is NOT a problem caused by NOx emissions is (1) addiction. Nitrogen oxides (NOx), including nitrogen dioxide (NO₂), are pollutants that arise primarily from the burning of fuel in cars, trucks, buses, power plants, and off-road equipment. When NOx reacts with water, oxygen, and other chemicals in the atmosphere, it forms nitric acid, which leads to acid rain. This acid rain can harm sensitive ecosystems, such as lakes and forests. Additionally, NOx contributes to the formation of photochemical smog and ground-level ozone, both of which are environmental and health concerns. Ground-level ozone can cause eye irritation and damage to the respiratory system, while photochemical smog reduces visibility and degrades air quality.
The formation of nitric acid, leading to acid rain, is a problem caused by NOx emissions. Acid rain harms sensitive ecosystems such as lakes and forests. Eye irritation and the formation of smog are also problems associated with NOx emissions. Addiction, on the other hand, is not a problem caused by NOx emissions.