• NOx exacerbates asthma, reduces lung function, and can lead to chronic lung damage. NOx also increases the susceptibility of young children and the elderly to respiratory infections.
• NOx also reacts in the presence of VOC’s and sunlight to form ground-level ozone, a major component of smog. Ozone irritates the eyes, damages the lungs, and aggravates respiratory problems. Ozone also reduces agricultural production and the growth rate of trees.
• NOx contributes to the formation of acid rain. Acid rain acidifies the soils and waters where it falls, killing plants, fish, and the animals that depend on them. Acid rain also causes property damage through the corrosion of buildings and monuments.
• NOx also contributes to nitrification (i.e., over-fertilization) of wetlands and bays, leading to algae blooms and fish kills.

Source - www.idontcareaboutair.com