Haze

Haze is in the air.

It is made of tiny bits of dust and smoke. These bits float in the sky. They make the air look cloudy. This can hide the sun. Haze can come from many places. It can come from big fires. It can come from cars or big factories. Wind can blow the haze to new lands. This makes it hard to see far away. It can even hide the stars at night.

Haze is a way the sky looks cloudy.

It happens when tiny bits float in the air. These bits are called particulates. They can be dust, smoke, or sand. Haze makes it hard to see far away. It can hide the sun or the stars at night.

Haze can come from many places. It can come from big fires or from cars. It can also come from volcanoes.

Sometimes, haze moves from one country to another. This happens when the wind blows it. In Southeast Asia, fires in forests caused big haze problems. The smoke moved across the sea to other lands. This is called transboundary haze.

Haze can also be made by chemicals. Gases from burning things can turn into tiny liquid drops. This is often called wet haze. This kind of haze usually happens in warm seasons. It can make it hard for solar power to work. It can also make it harder for plants to grow.

Haze is a way the sky looks cloudy or blurry. It happens when tiny dry bits called particulates float in the air. These bits can be dust, smoke, sand, or even volcanic ash. When these particles gather, they hide the clarity of the sky. This makes it hard for people to see things far away. Haze can look brownish or bluish depending on the sun.

Haze works by blocking light through a process called scattering. When light hits the tiny particles, it bounces around in different directions. This makes the sun or the landscape look less sharp. This effect is called a loss of contrast. In some cases, the haze is so thick that the sun disappears before it even hits the horizon.

Sometimes, haze can turn into mist. This happens when the particles act as a place for water to gather. These tiny water drops are called condensation nuclei. This creates what scientists call "wet haze."

People have studied haze for a long time to solve problems. In the United States, a program called IMPROVE was started. It is a team effort between the EPA and the National Park Service. They work together to find out what chemicals are in the haze. They want to make the air in National Parks clear again. They also use the Clean Air Act to protect 156 special areas.

There are many sources that create haze around the world. Farming can cause it through stubble burning or ploughing in dry weather. Traffic and industry also add smoke and dust to the air. In Southeast Asia, haze has been a huge problem since 1991. Large fires in Sumatra and Borneo create smoke that travels far. In 2013, Singapore saw a very high pollution level of 401.

Haze can even cause arguments between different countries. This is called transboundary haze because it moves across borders. Wind carries the smoke from one land into another land. In 2013, forest fires in Indonesia sent fumes to Malaysia. This made the air smell like ash and coal for over a week. Haze also affects how we use technology and food. It can block sunlight from reaching solar panels. It can also lower the amount of food that crops grow.

Haze is an atmospheric phenomenon involving suspended particulates that reduce visibility. These particles include dry substances like dust, smoke, sand, and volcanic ash. When these materials accumulate in the air, they obscure the clarity of the sky. The World Meteorological Organization classifies these particles into several categories. These include fog, ice fog, steam fog, mist, haze, smoke, volcanic ash, dust, sand, and snow. Haze is often distinguished from mist by the moisture in the air. While mist forms in saturated, humid air, haze is traditionally associated with dry air.

The way haze affects light is a process called the Tyndall effect. This is an aerial form of light scattering. Haze is spectrally selective according to the electromagnetic spectrum. This means it treats different colors of light differently. Shorter wavelengths, such as blue light, are scattered more easily. Longer wavelengths, such as red or infrared light, are scattered less. Because of this scattering, the sun or landscape may lose contrast. This can make sunrise and sunset colors appear subdued. In extreme cases, the sun may disappear before it reaches the horizon.

Scientists also study a specific type called "wet haze." This occurs when haze particles act as condensation nuclei. A condensation nucleus is a tiny surface where water vapor can gather. When vapor condenses on these particles, it forms mist droplets. Wet haze often arises from complex chemical reactions in the atmosphere. For example, sulfur dioxide gases from combustion can convert into sulfuric acid droplets. These reactions are enhanced by sunlight, high humidity, and a lack of wind. Some wet haze also comes from terpenes, which are compounds released by burning trees.

Many different human and natural activities create haze. Farming contributes through stubble burning or ploughing during dry weather. Traffic and industrial processes also release significant amounts of smoke and dust. Natural events like volcanic activity and wildfires are also major sources. In the United States, the IMPROVE program helps monitor these levels. This is a collaboration between the EPA and the National Park Service. They study the chemical composition of haze in National Parks. Their goal is to restore visibility to pre-industrial levels. The Clean Air Act also protects 156 Class I Federal areas from visibility problems.

In Southeast Asia, haze has been a major issue since 1991. Much of this smoke comes from fires in Sumatra and Borneo. Farmers, plantation owners, and miners often set fires to clear land. In 2013, forest fires in Indonesia caused a massive crisis in Malaysia. The air in Kuala Lumpur smelled of ash and coal for over a week. This was one of the worst environmental crises for the region since 1997. During the 2013 haze, Singapore reached a record Pollutant Standards Index of 401. Major crises also occurred in 1997 and 2015.

Haze can move across borders, creating what is called transboundary haze. This movement can cause international disputes between neighboring countries. Because wind carries the particulates, one nation's pollution becomes another's problem. This is a significant issue for nations like Indonesia, Malaysia, and Singapore. To manage this, ASEAN countries created a Regional Haze Action Plan in 1997. In 2002, they signed the Agreement on Transboundary Haze Pollution. This agreement includes a coordination and support unit hosted by the ASEAN secretariat.

Beyond visibility, haze has serious impacts on technology and food. One major effect is the reduction of irradiance, which is incoming solar radiation. This is a growing problem for the solar industry and photovoltaic production. Haze can also lower agricultural yields by blocking sunlight. These issues are particularly difficult for agrivoltaics. Agrivoltaics is the practice of combining solar power production with food agriculture. Therefore, controlling pollution can actually help increase total food production in places like China.