What is the largest source of air pollution 😨

Air pollution consists(গঠিত) of chemicals or particles in the air that can harm the health of humans, animals, and plants. It also damages(ক্ষতি) buildings. Pollutants(দূষণকারী) in the air take many forms. They can be gases, solid particles, or liquid droplets(বিন্দু).

Sources of Air Pollution

Pollution enters the Earth's atmosphere(বায়ুমণ্ডল) in many different ways. Most air pollution is created by people, taking the form of emissions from factories, cars, planes, or aerosol cans. Second-hand cigarette smoke is also considered(বিবেচনা করা) air pollution. These man-made sources of pollution are called anthropogenic(নৃতাত্ত্বিক) sources.

Some types of air pollution, such as smoke from wildfires(দাবানল) or ash from volcanoes, occur naturally. These are called natural sources.

Air pollution is most common in large cities where emissions(নির্গমন) from many different sources are concentrated. Sometimes, mountains or tall buildings prevent air pollution from spreading(পাতন) out. This air pollution often appears(প্রদর্শিত) as a cloud making the air murky. It is called smog. The word "smog" comes from combining(সমন্বয়) the words "smoke" and "fog."

Large cities in poor and developing(উন্নয়নশীল) nations tend to have more air pollution than cities in developed nations. According to the World Health Organization (WHO), some of the worlds most polluted cities are Karachi, Pakistan; New Delhi, India; Beijing, China; Lima, Peru; and Cairo, Egypt. However, many developed nations also have air pollution problems. Los Angeles, California, is nicknamed Smog City.

Indoor Air Pollution

Air pollution is usually thought of as smoke from large factories(কারখানা) or exhaust from vehicles. But there are many types of indoor(গৃহমধ্যস্থ) air pollution as well.

Heating a house by burning substances such as kerosene, wood, and coal can contaminate(দূষিত করা) the air inside the house. Ash and smoke make breathing difficult, and they can stick to walls, food, and clothing.

Naturally-occurring radon(রেডন) gas, a cancer-causing material, can also build up in homes. Radon is released through the surface(পৃষ্ঠতল) of the Earth. Inexpensive(সস্তা) systems installed by professionals can reduce radon levels.

Some construction(নির্মাণ) materials, including insulation, are also dangerous to people's health. In addition, ventilation(অবাধে বায়ু - চলাচলের ব্যবস্থা), or air movement, in homes and rooms can lead to the spread of toxic(বিষাক্ত) mold. A single colony of mold may exist in a damp, cool place in a house, such as between walls. The mold's spores enter the air and spread throughout(সর্বত্র) the house. People can become sick from breathing in the spores.