Vehicle emissions, particularly from diesel engines, contribute significantly to air pollution in urban areas due to the release of harmful pollutants such as particulate matter, nitrogen oxides, and hydrocarbons.

Particulate matter, especially fine particulate matter (PM2.5), is a major air pollutant that can penetrate deep into the lungs and cause respiratory problems, cardiovascular diseases, and other health issues.

Photochemical smog is a type of air pollution that occurs when sunlight reacts with pollutants such as nitrogen oxides and volatile organic compounds, resulting in the formation of ground-level ozone and other harmful pollutants.

Sulfur dioxide is a major air pollutant that contributes to acid rain when it reacts with water vapor in the atmosphere, forming sulfuric acid and other acidic compounds.

Carbon dioxide is the primary greenhouse gas emitted by human activities, particularly through the burning of fossil fuels, and is a major contributor to global warming and climate change.

Chlorofluorocarbons (CFCs) are synthetic chemicals that were widely used in refrigeration, aerosols, and other applications, and are primarily responsible for the depletion of the ozone layer in the Earth's stratosphere.

Air purification is the process of removing pollutants from the air, typically through the use of filters, scrubbers, or other technologies, to improve air quality.

The Paris Agreement is an international agreement that aims to reduce greenhouse gas emissions and limit global warming to well below 2 degrees Celsius, preferably to 1.5 degrees Celsius, compared to pre-industrial levels.

Emission control refers to the techniques and technologies used to reduce the release of pollutants into the air at their source, such as catalytic converters in vehicles or scrubbers in industrial facilities.

Ozone is a major air pollutant that is formed through the reaction of sunlight with nitrogen oxides and volatile organic compounds, and is a primary component of smog.

Air quality monitoring involves the collection and analysis of data on air pollutants to assess the current state of air quality and track changes over time.

Sulfur dioxide is a major air pollutant that contributes to acid rain when it reacts with water vapor in the atmosphere, forming sulfuric acid and other acidic compounds.

Smart growth refers to the planning and development strategies that aim to reduce air pollution and promote sustainable urban development through compact urban design, mixed-use development, and efficient transportation systems.

Ozone is a major air pollutant that is formed through the reaction of sunlight with nitrogen oxides and volatile organic compounds, and is a primary component of smog.

Air quality monitoring involves the collection and analysis of data on air pollutants to assess the current state of air quality and track changes over time.