Haze Mystery: Unraveling The Causes Of Pollution

Haze is an atmospheric phenomenon that occurs when dust, smoke, and other dry particulates are suspended in the air, reducing visibility and the clarity of the sky. Haze is a form of air pollution that can have significant impacts on human health, the environment, and various economic sectors. It is caused by a variety of sources, including industrial emissions, vehicle emissions, power plant sulfate plumes, wildfires, and agricultural practices such as stubble burning. Haze can also be transboundary, affecting multiple countries in a region, as seen in the Southeast Asian haze of 1997, which cost the region USD 1.4 billion in short-term health costs and led to the hospitalisation of over 40,000 people.

Haze is a form of wet air pollution

Haze is a form of air pollution that impairs visibility and poses serious health risks. It is traditionally defined as an atmospheric phenomenon where dust, smoke, and other dry particulates are suspended in the air, reducing the clarity of the sky. However, haze is now recognised as a form of "wet" air pollution in certain regions, particularly in the eastern United States.

The term "wet haze" refers to a vast blanket of man-made pollution composed of tiny droplets (aerosols) of condensed pollutants. This type of haze is distinct from the more common "dry haze," which consists of fine dust particles, such as the Harmattan of West Africa or the Shamal wind haze of the Persian Gulf. The distinction between "wet" and "dry" haze is important as it helps characterise the composition and behaviour of the haze.

The formation of wet haze is influenced by weather conditions that prevent the dispersal of smoke and other pollutants. These pollutants concentrate and form a typically low-hanging shroud, impairing visibility and posing respiratory health risks. Industrial pollution, for instance, can lead to dense haze, known as smog, which has been linked to reduced agricultural yield and health issues. Smog is a form of wet haze, as it contains acid droplets that are hazardous to exposed tissues in the lungs and breathing passages.

The sources of haze-causing particles include farming practices (stubble burning, ploughing in dry weather), traffic, industry, windy weather, volcanic activity, and wildfires. Haze can have far-reaching impacts, affecting terrestrial photography, aviation, and human health. It has also become a cause of international disputes, as haze can migrate to adjacent countries through wind, as seen in the Southeast Asian haze crisis in 2013, affecting Indonesia, Malaysia, and Singapore.

To address haze, various measures have been implemented, such as the Interagency Monitoring of Protected Visual Environments (IMPROVE) program in the United States, which aims to establish the chemical composition of haze and implement air pollution control measures. Additionally, the Clean Air Act mandates addressing current visibility problems and preventing future ones in designated Class I Federal areas. These efforts reflect the recognition of haze as a significant environmental and health concern.

Haze is caused by smoke, dust, and other dry particulates

Haze is a vast blanket of man-made pollution that consists of smoke, dust, and other dry particulates. It is traditionally an atmospheric phenomenon in which dust, smoke, and other dry particulates are suspended in the air, obscuring visibility and the clarity of the sky. Haze is often the result of suspended dust and smoke particles accumulating in relatively dry air. When weather conditions prevent the dispersal of smoke and other pollutants, they concentrate and form a usually low-hanging shroud that impairs visibility and can become a respiratory health threat if inhaled in large quantities.

Haze is typically caused by industrial pollution, which results in a dense haze known as smog. Smog is a brownish, photochemically enhanced form of air pollution derived from automobile exhausts. It has been linked to reduced agricultural yield and has been identified as a contributing factor to international disputes between neighbouring countries. For example, in 2013, forest fires in Indonesia caused Kuala Lumpur and the surrounding areas to be enveloped in a pall of noxious fumes, resulting in one of the country's worst environmental crises.

Natural sources of haze do exist, such as the haze derived from volatile gases emitted by trees in the Blue Ridge and Great Smoky Mountains of the Appalachians. However, the haze commonly observed in the eastern United States during the summer is predominantly a result of human activities. Studies have shown that warm-season haze over the eastern United States is largely composed of sulfate aerosols, which are stable and can remain airborne for days, travelling long distances before settling as acid rain or snow.

Particulate matter pollution, including haze-causing particles emitted directly into the air or formed from gases, is a major cause of reduced visibility in parts of the United States, including national parks. These haze-causing particles have been linked to serious health issues, environmental damage, and the formation of acid rain, which harms aquatic ecosystems and erodes buildings and monuments. The economic impact of haze extends to manufacturing, agriculture, transport, and tourism, and it has also been implicated in accidents, including aviation incidents.

Haze can be a transboundary issue, affecting multiple countries

Haze is an atmospheric phenomenon that reduces visibility and the clarity of the sky. It is caused by dust, smoke, and other dry particulates suspended in the air. Haze is no longer just a domestic problem but has become a transboundary issue, affecting multiple countries.

In the United States, haze is particularly noticeable in the Blue Ridge and Great Smoky Mountains of the Appalachians. The haze in these regions is believed to be derived from volatile gases emitted by trees. Haze in the US has also been linked to vehicle emissions and power plant sulfate plumes, which have led to reduced visibility in national parks in Arizona and Utah.

In Southeast Asia, haze has been a recurring problem since 1972, with the 1997 and 2015 events being the most severe. The main sources of haze in this region are smoke from fires in Sumatra and Borneo and forest fires in Indonesia, which have affected neighboring countries such as Malaysia and Singapore. The ASEAN countries have recognized the severity of the issue and agreed on a Regional Haze Action Plan in 1997, followed by the Agreement on Transboundary Haze Pollution in 2002.

Haze can have far-reaching impacts on multiple countries, affecting not only air quality and visibility but also human health, the environment, and economic activities. It can lead to respiratory issues, contribute to greenhouse gas emissions, harm wildlife, and reduce agricultural yield. The transboundary nature of haze highlights the need for international cooperation and joint efforts to address and mitigate its adverse effects.

Haze is linked to respiratory issues and other health problems

Haze is a type of atmospheric phenomenon that occurs when dust, smoke, and other dry particulates become suspended in the air, reducing visibility and impairing the clarity of the sky. It is primarily caused by particulate matter pollution, with sources including industrial pollution, farming practices, traffic, wildfires, and volcanic activity. Haze has been linked to a range of respiratory issues and other health problems, particularly in vulnerable populations.

The health effects of haze have been well-documented, with scientific studies establishing links between particle pollution exposure and adverse health outcomes. These studies have found that exposure to particulate matter can lead to increased respiratory symptoms, such as irritation of the airways, coughing, and difficulty breathing. People with pre-existing heart or lung diseases, children, older adults, and individuals from minority and low socioeconomic status populations are particularly susceptible to the health impacts of haze.

In regions with high levels of air pollution, such as China, haze has been associated with a range of respiratory infections and other diseases. For example, during periods of extreme haze in Shanghai and the Pearl River Delta region, there was a re-emergence of human infection with avian influenza A H7N9 virus, leading to an increased number of deaths. Additionally, environmental epidemiology research has shown that hazy weather conditions are linked to increased morbidity due to respiratory infections and an elevated risk of other diseases.

The 1952 "killer smog" episode in London, primarily caused by smoke from coal combustion, provides a stark illustration of the health impacts of haze. This event resulted in approximately 4,000 premature deaths, highlighting the potential severity of the health risks associated with air pollution. While the direct link between haze and mortality in China has not been scientifically established, the chronic effects of high levels of pollutants on respiratory health, including lung cancer, are a significant concern.

Furthermore, haze has been linked to allergic diseases, particularly asthma. Studies have suggested an association between environmental pollution and the prevalence and exacerbation of asthma. The increasing trend of industrialization and urbanization in Asia has led to severe air pollution in many cities, resulting in frequent episodes of haze and unsafe air quality levels. These episodes of haze are often caused by a combination of factors, including exhaust emissions from motor vehicles, coal burning, dust storms, and construction dust, which interact to produce high concentrations of secondary pollutants.

Haze affects aviation and terrestrial photography

Haze is an atmospheric phenomenon that occurs when dust, smoke, and other dry particles are suspended in the air, obscuring visibility. It is caused by a variety of sources, including industrial pollution, agricultural practices, traffic, wildfires, and volcanic activity. Haze has become a significant issue, leading to international disputes among neighbouring countries as it can easily migrate across borders.

Impact on Aviation Photography

Haze can significantly impact aviation photography, particularly when shooting with a long lens or telephoto lens. The atmospheric distortion caused by haze can result in blurry or unsharp images, even with proper camera settings. The impact of haze on aviation photography is more pronounced when photographing distant subjects as the amount of disturbed air between the camera and the subject increases. To mitigate this issue, photographers can try to reduce the distance between themselves and the subject or wait for the subject to move closer. Additionally, avoiding shooting over heated surfaces, such as asphalt roads, and focusing on higher subjects can help reduce the impact of haze.

Impact on Terrestrial Photography

Haze can also affect terrestrial photography, including landscape and astrophotography. It can result in a loss of contrast, dull scenes, and reduced clarity in images. The light scattering and reflection through haze particles can cause a subdued appearance of sunrise and sunset colours and even the sun itself. In some cases, the sun may disappear before reaching the horizon due to the attenuation of haze. Photographers can use techniques such as adding a polarizer to reduce scattered light and using post-processing adjustments to decrease the haze effect and enhance image clarity.

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