Ozone is a secondary air pollutant, formed by the reaction of nitrogen oxides and hydrocarbons in the presence of sunlight.

Vehicle emissions are the main source of air pollution in urban areas, contributing to high levels of carbon monoxide, nitrogen oxides, and particulate matter.

Particulate matter, especially fine particulate matter (PM2.5), is the most harmful air pollutant to human health, as it can penetrate deep into the lungs and cause respiratory and cardiovascular problems.

The Clean Air Act is a law that regulates air pollution in the United States, and it sets limits on the emission of air pollutants from various sources.

Increasing the number of vehicles on the road will increase air pollution, as more vehicles will be emitting pollutants.

The main goal of the Paris Agreement is to reduce greenhouse gas emissions, in order to limit global warming and climate change.

Natural gas is a fossil fuel, and therefore not a renewable energy source.

Renewable energy sources produce less air pollution than fossil fuels, as they do not emit greenhouse gases or other pollutants.

Increasing industrial production will increase air pollution, as more industries will be emitting pollutants.

The main goal of the Montreal Protocol is to protect the ozone layer by reducing the production and consumption of ozone-depleting substances.

Nitrogen is not a greenhouse gas, as it does not trap heat in the atmosphere.

Emissions from power plants, especially sulfur dioxide and nitrogen oxides, are the main cause of acid rain.

Increasing the number of power plants will increase air pollution, as more power plants will be emitting pollutants.

The main goal of the Kyoto Protocol is to reduce greenhouse gas emissions, in order to limit global warming and climate change.

Increasing the number of livestock will increase air pollution, as more livestock will be producing methane and other pollutants.