Air quality guideline

Air quality guideline

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Comparison of air pollution exposure limits in cities according to EU and WHO guidelines

Air quality guidelines are recommendations by health organizations, such as the World Health Organization (WHO), to protect public health from the adverse effects of air pollution. These guidelines provide limits for various pollutants in the air, aiming to reduce the risk of health problems associated with air pollution exposure.

Overview

Air quality guidelines are established to inform policymakers and the public about the levels of air pollution that are considered safe for human health. They are based on scientific evidence and are periodically updated to reflect new research findings. The guidelines cover a range of pollutants, including particulate matter (PM), ozone (O_), nitrogen dioxide (NO_), and sulfur dioxide (SO_).

Key Pollutants

Particulate Matter (PM)

Particulate matter is a mixture of solid particles and liquid droplets found in the air. It includes PM10 and PM2.5, which refer to particles with diameters of 10 micrometers and 2.5 micrometers, respectively. PM2.5 is particularly harmful as it can penetrate deep into the lungs and even enter the bloodstream.

Ozone (O_)

Ozone at ground level is a harmful air pollutant. It is a major component of smog and can cause respiratory problems, particularly in children and the elderly. Ozone is formed when pollutants emitted by cars, power plants, and other sources react in sunlight.

Nitrogen Dioxide (NO_)

Nitrogen dioxide is a reddish-brown gas with a characteristic sharp, biting odor. It is a significant air pollutant and contributes to the formation of smog and acid rain. NO_ can irritate the lungs and lower resistance to respiratory infections.

Sulfur Dioxide (SO_)

Sulfur dioxide is a colorless gas with a pungent, irritating smell. It is produced by volcanic eruptions and industrial processes, particularly the burning of coal and oil at power plants and the refining of oil. SO_ can cause respiratory problems and contribute to the formation of fine particulate pollution.

Health Impacts

Exposure to air pollution is linked to a range of health problems, including respiratory infections, heart disease, stroke, and lung cancer. Vulnerable populations, such as children, the elderly, and those with pre-existing health conditions, are particularly at risk. The WHO air quality guidelines aim to minimize these health risks by setting limits on pollutant concentrations.

Implementation

While the WHO provides global guidelines, individual countries and regions may set their own air quality standards based on local conditions and priorities. For example, the European Union has its own air quality standards, which are sometimes less stringent than the WHO guidelines.

Related pages

• Air pollution
• World Health Organization
• Environmental health
• Public health