The AQI is designed to provide a simple and standardized way to communicate air quality conditions to the public, helping them understand the potential health risks associated with air pollution.

Sulfur dioxide (SO2) is not directly included in the calculation of the AQI, although it can contribute to the formation of particulate matter (PM), which is a component of the AQI.

The AQI is expressed in Air Quality Index Units (AQIU), which are calculated based on the concentrations of various air pollutants.

An AQI value between 0 and 50 is considered "Good", indicating that air quality poses little or no risk to human health.

Vehicle exhaust is a major source of particulate matter (PM) in urban areas, particularly diesel engines and older vehicles.

Ground-level ozone (O3) is a major component of smog, formed through chemical reactions between nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight.

Exposure to high levels of carbon monoxide (CO) can lead to cardiovascular problems, including increased risk of heart attacks and strokes, particularly in individuals with pre-existing heart conditions.

Allowing more industrial emissions would worsen air quality, as industrial activities are a major source of air pollution.

Vehicle exhaust, particularly from diesel engines, is a major source of nitrogen oxides (NOx) emissions, contributing to the formation of ground-level ozone and smog.

Sulfur dioxide (SO2) is a major contributor to acid rain, as it reacts with water vapor in the atmosphere to form sulfuric acid.

Exposure to high levels of particulate matter (PM) can lead to reduced lung function, increased asthma attacks, and other respiratory problems, particularly in children and individuals with pre-existing respiratory conditions.

While trees and plants can release VOCs, they are generally not considered a major source of air pollution compared to human-made sources such as gasoline, paints, and cleaning products.

Exposure to high levels of ground-level ozone (O3) can cause respiratory irritation, coughing, and difficulty breathing, particularly in individuals with pre-existing respiratory conditions.

Increasing the speed limit on highways would increase vehicle emissions, as vehicles consume more fuel and produce more pollutants at higher speeds.

Agricultural activities, such as livestock farming and crop production, can contribute to air pollution through the release of ammonia, methane, and other pollutants.