Vehicle exhaust, particularly from diesel engines, is a significant contributor to air pollution in urban areas due to the emission of harmful pollutants such as nitrogen oxides, particulate matter, and hydrocarbons.

Smog is primarily composed of ozone, a secondary pollutant formed by the reaction of nitrogen oxides and volatile organic compounds in the presence of sunlight.

Particulate matter, especially fine particles (PM2.5), can penetrate deep into the lungs and cause inflammation and irritation, leading to respiratory problems.

Air purification refers to the process of removing contaminants and pollutants from the air, typically using various technologies such as filters, scrubbers, and electrostatic precipitators.

Solar power is a clean and renewable energy source that does not produce air pollution during electricity generation, making it an effective alternative to fossil fuels in urban areas.

The photovoltaic effect refers to the process by which certain materials, such as semiconductors, generate an electrical current when exposed to light, enabling the conversion of sunlight into electricity.

Sulfur dioxide is a major air pollutant emitted by power plants and industrial facilities that burn fossil fuels, particularly coal, and can contribute to acid rain and respiratory problems.

Water treatment encompasses various processes aimed at removing contaminants and pollutants from wastewater, including physical, chemical, and biological methods, to make it safe for discharge or reuse.

Nitrogen oxides, particularly nitrogen dioxide, are emitted by vehicles and contribute to the formation of smog and ground-level ozone, which can cause respiratory problems and environmental damage.

Air scrubbing involves passing polluted air through a liquid or solid absorbent to remove pollutants by absorption, adsorption, or chemical reaction.

Ammonia is a common air pollutant emitted from agricultural activities, particularly livestock farming, and can contribute to poor air quality and environmental problems such as eutrophication.

Vehicle emission standards are regulations that limit the amount of pollutants that can be emitted by vehicles, helping to reduce air pollution from transportation sources.

Nitrogen dioxide is a common air pollutant emitted from household activities that involve burning fossil fuels, such as cooking and heating, and can contribute to indoor and outdoor air pollution.

Urban forestry involves planting and managing trees and other vegetation in urban areas to improve air quality, reduce heat island effects, and provide other environmental benefits.

Sulfur dioxide is a common air pollutant emitted from industrial processes that involve burning sulfur-containing fuels or processing sulfur-containing materials, such as metal smelting and refining.