Air quality guideline

Air Quality Guidelines (AQGs) are standards set to protect public health from the harmful effects of air pollution. They are based on scientific evidence and are designed to offer guidance on the limits of key air pollutants. The World Health Organization (WHO) and various national and international bodies establish these guidelines to help countries and regions improve air quality and protect human health.

Overview

Air quality is determined by the concentrations of pollutants in the air, which can have significant impacts on human health, ecosystems, and the climate. Pollutants of major public health concern include particulate matter (PM), ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2), among others. The AQGs provide target values for these pollutants, aiming to reduce levels of exposure and mitigate health risks.

Particulate Matter (PM)

Particulate matter is a complex mixture of extremely small particles and liquid droplets suspended in the air. PM is classified by size into PM10 (particles with a diameter of 10 micrometers or smaller) and PM2.5 (particles with a diameter of 2.5 micrometers or smaller). The WHO Air Quality Guidelines recommend reducing PM2.5 to an annual mean of 5 µg/m^3 to significantly lower disease risk.

Ozone (O3)

Ozone at ground level is created by the reaction of sunlight on air containing hydrocarbons and nitrogen oxides. It is a major component of smog and has been linked to respiratory diseases and other health problems. The AQGs suggest an 8-hour mean target of 100 µg/m^3 to protect the public health.

Nitrogen Dioxide (NO2)

Nitrogen dioxide is a significant air pollutant, primarily produced by road traffic and other fossil fuel combustion processes. Long-term exposure to NO2 may lead to reduced lung function and increased risk of respiratory conditions. The AQGs set an annual mean limit of 40 µg/m^3.

Sulfur Dioxide (SO2)

Sulfur dioxide is produced from the burning of fossil fuels (coal and oil) and the smelting of mineral ores that contain sulfur. Short-term exposure to SO2 can lead to throat and eye irritation and can affect lung function. The AQGs recommend a 24-hour mean limit of 20 µg/m^3.

Implementation and Challenges

Implementing air quality guidelines requires concerted efforts from governments, industries, and communities. Strategies include monitoring air quality, regulating emissions, promoting cleaner transportation, and raising public awareness. However, challenges such as economic constraints, lack of infrastructure, and political will can impede progress.

Conclusion

Air Quality Guidelines are crucial tools in the global effort to protect human health from the adverse effects of air pollution. By adhering to these guidelines, countries can significantly reduce the burden of disease related to air pollution and improve the quality of life for their citizens.