Motor vehicles, particularly those powered by fossil fuels, emit various pollutants such as nitrogen oxides, particulate matter, and hydrocarbons, contributing significantly to air pollution in urban environments.

Carbon dioxide (CO2) is the primary greenhouse gas emitted by the burning of fossil fuels, such as coal, oil, and natural gas. It contributes significantly to the greenhouse effect and global warming.

Solar photovoltaic (PV) systems generate electricity directly from sunlight without emitting air pollutants during the process. Wind turbines and hydroelectric power plants also produce electricity without direct emissions, while biomass power plants may emit some pollutants depending on the type of biomass used.

Energy efficiency refers to the practice of using less energy to perform the same task or achieve the same level of comfort. It involves implementing measures to reduce energy consumption without sacrificing essential services or amenities.

Coal-fired power plants emit various air pollutants, including sulfur dioxide (SO2). SO2 is a major contributor to acid rain and can cause respiratory problems in humans and harm ecosystems.

Energy sustainability refers to the ability of an energy system to meet current and future energy needs while minimizing negative environmental impacts and ensuring social equity. It involves the use of renewable energy sources, energy efficiency measures, and responsible energy management practices.

Vehicle exhaust is a significant source of particulate matter (PM) air pollution in urban areas. PM includes fine particles and coarse particles, which can cause respiratory problems and other health issues.

Natural gas combustion primarily emits nitrogen oxides (NOx), which contribute to the formation of ground-level ozone and smog. NOx emissions can also lead to respiratory problems and environmental damage.

Reducing air pollution from power plants involves a combination of strategies, including using renewable energy sources, implementing energy efficiency measures, and installing pollution control technologies such as scrubbers and filters.

Energy conversion refers to the process of transforming one form of energy into another. This can involve converting electrical energy to mechanical energy, chemical energy to electrical energy, or thermal energy to electrical energy, among other conversions.

Agricultural activities, such as the use of fertilizers and pesticides, can contribute to air pollution in rural areas. Ammonia emissions from livestock and nitrogen oxides from fertilizer application can impact air quality.

Diesel engines emit significant amounts of particulate matter (PM), which includes fine particles and coarse particles. PM can cause respiratory problems and other health issues, and it can also contribute to climate change.

Reducing air pollution from vehicles involves a combination of strategies, including using electric vehicles, implementing stricter emissions standards, and promoting public transportation and carpooling.

Energy intensity refers to the amount of energy used per unit of time, often expressed in units such as kilowatt-hours per year (kWh/yr). It is a measure of how efficiently energy is being used.

In developing countries, household cooking and heating using traditional fuels such as wood, charcoal, and kerosene can be a significant source of air pollution, particularly in urban areas.