Air Pollution: Global Standards For Clear Indication

Air pollution is a pressing global issue that poses a significant threat to human health and the environment. It is a complex mixture of solid particles, liquid droplets, and gases, with sources ranging from household fuel burning to industrial activities and agricultural practices. To address this issue, organizations like the World Health Organization (WHO) have developed air quality guidelines (AQG) to provide global targets for governments to improve air quality and protect public health. These guidelines are based on extensive research and aim to reduce the health risks associated with air pollution, which has been linked to various diseases and adverse effects on multiple organ systems. While there is no single international standard for air pollution indication, the WHO's AQG serves as a reference for countries to establish their own air quality standards and policies. The Air Quality Index (AQI), used by organizations like the US EPA, is another tool that helps monitor and communicate air quality levels to the public, with specific categories and colors indicating the level of health concern.

WHO Air Quality Guidelines

The World Health Organization's Air Quality Guidelines (AQG) are a set of evidence-based recommendations for limit values of specific air pollutants. The guidelines are designed to help countries achieve air quality that protects public health. The first release of the guidelines was in 1987, and several updated versions have appeared since then, with the latest global version published in 2005. The 2021 update of the WHO air quality guidelines is in response to the real and continued threat of air pollution to public health.

The guidelines are based on systematic literature reviews, rigorous evaluation methods, and extensive consultation with experts and end-users of the guidelines from all regions of the world. They incorporate scientific evidence from multiple countries, making them relevant to diverse conditions around the world and capable of supporting a broad range of policy options for air quality management. The guidelines are neither standards nor legally binding criteria, but they offer guidance in reducing the health impacts of air pollution based on expert evaluation of current scientific evidence.

The WHO Air Quality Guidelines recommend levels and interim targets for common air pollutants: PM, O3, NO2, and SO2. These pollutants are measured as PM2.5 and PM10 (particles with an aerodynamic diameter of equal to or less than 2.5, also called fine, and 10 micrometres, respectively), ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), and sulfur dioxide (SO2). Fine particulate matter (PM2.5) can penetrate the lungs and enter the body through the bloodstream, affecting all major organs. Exposure to PM2.5 can cause diseases in both the cardiovascular and respiratory systems, such as stroke, lung cancer, and chronic obstructive pulmonary disease (COPD).

The guidelines serve as a global target for national, regional, and city governments to work towards improving their citizens' health by reducing air pollution. Air pollution is a complex mixture of solid particles, liquid droplets, and gases that can come from various sources, including household fuel burning, industrial chimneys, traffic exhausts, power generation, open burning of waste, agricultural practices, and desert dust. It poses a significant threat to people worldwide and is the greatest environmental threat to health, leading to non-communicable diseases such as heart attacks, stroke, and cancer. According to the World Health Organization, there are 7 million premature deaths every year due to the combined effects of outdoor and household air pollution.

Air Quality Index (AQI) Basics

The Air Quality Index (AQI) is a tool for reporting and communicating about outdoor air quality and health. The AQI is an index for reporting daily air quality, telling us how clean or polluted the air is and what associated health effects might be a concern, especially for ground-level ozone and particle pollution. The higher the AQI value, the greater the level of air pollution and the more serious the health concern.

The AQI is divided into six categories, each with a different level of health concern and a specific colour. An AQI value of 50 or below represents good air quality, while a value over 300 represents hazardous air quality. AQI values at or below 100 are generally considered satisfactory, and when they are above 100, the air quality is unhealthy for certain sensitive groups of people and then for everyone as values increase.

The EPA establishes an AQI for five major air pollutants regulated by the Clean Air Act. Each of these pollutants has a national air quality standard set by the EPA to protect public health. The AQI is used to monitor criteria pollutants or concentration ranges for certain PM species like organic carbon, nitrates, and sulfates.

The World Health Organization (WHO) has also developed global Air Quality Guidelines (AQG) that serve as a target for governments to improve the health of their citizens by reducing air pollution. The WHO regularly integrates scientific evidence on the health impacts of air pollution and monitors countries' air quality progress.

Air pollution sources

Air pollution is a complex mixture of solid particles, liquid droplets, and gases. It is considered the greatest environmental threat to health and is a leading cause of non-communicable diseases, causing around 7 million premature deaths each year.

There are various sources of air pollution, which can be categorized as mobile, stationary, area, and neighborhood sources. Mobile sources, such as automobiles, cars, trucks, trains, and boats, account for more than half of the air pollution in the United States. Stationary sources, like power plants, emit large amounts of pollution from a single location and are also known as point sources. Area sources are made up of multiple smaller pollution sources that may not be significant on their own but can collectively have an impact. Natural sources, like desert dust, can be classified as area sources, although they typically do not create long-term air pollution issues.

Neighborhood sources are common sources of air pollution that people are frequently exposed to, including vehicles, local businesses, heating and cooling equipment, wood fires, and gas-powered yard equipment. Residential wood burning, for instance, accounted for 55% of Minnesota's fine particle emissions. While emissions from other sources are declining, wood smoke pollution is increasing. Additionally, neighborhood sources are challenging to mitigate due to their prevalence and number.

Health effects of air pollution

Air pollution is a complex mixture of solid particles, liquid droplets, and gases. It can come from many sources, including household fuel burning, industrial chimneys, traffic exhausts, power generation, open burning of waste, agricultural practices, desert dust, and more. The World Health Organization (WHO) identifies and monitors the most harmful air pollutants to support countries in reducing health risks.

The health consequences of air pollution are severe and include an increased risk of respiratory infections, heart disease, and lung cancer. Outdoor air pollution is responsible for millions of premature deaths each year from heart attacks, strokes, diabetes, and respiratory diseases. Those most at risk are children, the elderly, people with existing diseases, and minority and low-income communities.

Short-term exposure to ozone, for example, can cause chest pain, coughing, and throat irritation, while long-term exposure can lead to decreased lung function and chronic obstructive pulmonary disease (COPD). Other pollutants, such as sulfur dioxide, irritate the eyes, worsen asthma, and increase susceptibility to respiratory infections. Fine particulate matter (PM2.5) can penetrate the lungs and enter the bloodstream, affecting all major organs. Exposure to PM2.5 has been linked to cardiovascular and respiratory diseases, including stroke, lung cancer, and COPD.

Additionally, air pollution has been associated with adverse mental health outcomes. Studies have found a link between poor air quality and an increased rate of bipolar disorder and major depression. Research has also shown an association between prenatal exposure to high levels of air pollution and developmental delays, as well as psychological and behavioural problems later in life, including symptoms of attention deficit hyperactivity disorder (ADHD), anxiety, and depression.

To protect public health, the WHO has developed Air Quality Guidelines (AQG) as a global target for governments to improve air quality and reduce air pollution. The AQG includes limit values for specific air pollutants, and countries can refer to the WHO's database of national air quality standards to inform their efforts to achieve the AQG.

Economic impact of air pollution

Air pollution has a significant economic impact on countries worldwide. It is responsible for a range of economic costs, including healthcare expenditures associated with pollution-related illnesses and deaths, environmental damage, and lost ecosystem services. According to the World Bank, the health damage caused by air pollution costs $6 trillion annually, equivalent to a 5% reduction in global GDP. This includes the impact on workforce productivity, with 1.2 billion workdays lost globally each year due to air pollution, a figure projected to reach 3.8 billion by 2060.

The economic impact of air pollution varies across different sectors. The top four sectors responsible for the highest external damages are agriculture, utilities, manufacturing, and transportation, contributing to just under 20% of GDP but over 75% of all air pollution-related damages. For example, the agriculture sector incurred $230 billion in air pollution damages in 2014, while the utilities sector saw a significant decrease in damages from 2008 to 2014, falling by more than 50%.

The burning of fossil fuels, a major contributor to air pollution, has been associated with substantial costs. In the United States, air pollution exposure from fossil fuels results in an estimated additional $2,500 in medical bills per person. When coupled with higher temperatures, leading to increased ozone pollution, the annual health costs in the US rise to $7.9 billion. Additionally, wildfire smoke, which is also a significant component of air pollution, costs Americans $16 billion annually, associated with respiratory hospital visits.

Air pollution control measures have proven effective in mitigating these economic impacts. For instance, research on the Clean Air Act in the United States revealed a 30:1 ratio between the economic benefits and the costs of air pollution mitigation. Similarly, air pollution reduction initiatives in the EU have resulted in economic gains of €50-60 billion annually since 2014. These findings highlight the significant economic benefits that can be achieved through cleaner technology and green industry development.

While the economic impact of air pollution is substantial, it is important to recognize that the costs associated with air pollution are often underestimated. As such, the potential economic benefits of implementing air pollution reduction strategies may be even greater than currently estimated.

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