Gaseous Pollutants: Understanding Their Impact On Our Environment

Gaseous pollutants are harmful substances that exist in a gaseous state and can be found in both indoor and outdoor environments. They are often the result of human activities such as combustion, respiration, and industrial processes. These pollutants can have detrimental effects on human health, with sensitivity varying from person to person. Examples of gaseous pollutants include carbon monoxide, nitrogen dioxide, and sulfur dioxide. Indoor sources of gaseous pollutants include cooking, heating, and lighting with dirty technologies, while outdoor sources include transportation, industrial activities, and power plants. Understanding and mitigating the impact of gaseous pollutants on human health is crucial for creating a safe and comfortable environment.

Carbon Monoxide

The toxic nature of carbon monoxide lies in its ability to bind to haemoglobin in the blood, forming carboxyhaemoglobin. This binding has a much higher affinity than the binding of oxygen to haemoglobin, which is essential for the body's cells to function. Therefore, carbon monoxide exposure can lead to a significant reduction in the transport of oxygen throughout the body, potentially resulting in tissue damage and even death.

The effects of carbon monoxide poisoning can vary depending on the concentration of the gas and the duration of exposure. Acute exposure, defined as lasting 24 hours or less, can cause headaches, dizziness, nausea, and confusion. Prolonged exposure, or chronic exposure, defined as longer than 24 hours, can lead to more severe symptoms, including loss of consciousness, respiratory failure, and even death.

To protect public health, organisations like the World Health Organization (WHO) and the United States Environmental Protection Agency (EPA) have established guidelines and standards for carbon monoxide levels. These standards aim to ensure that carbon monoxide is maintained at safe levels in indoor and outdoor environments, minimising the risk of adverse health effects for individuals.

Nitrogen Dioxide

There are national air quality standards in place to limit the levels of NO2 in outdoor air. EPA's national and regional rules to reduce NO2 emissions will help state and local governments meet the National Ambient Air Quality Standard (NAAQS). Under the federal Clean Air Act, more protective standards have helped drive down nitrogen dioxide emissions. Power plants, industrial sites, and on-road vehicles are cleaner than they used to be, improving overall air quality.

Radon

The International Agency for Research on Cancer (IARC) has classified radon as a proven human carcinogen, similar to tobacco smoke, asbestos, and benzene. Radon-222, produced by the decay of uranium-238 or radium-226, is the most dangerous isotope of radon. It has a long decay rate, allowing it to accumulate indoors, especially in regions with high concentrations of uranium-238 or radium-226 in the ground or building materials.

Asbestos

However, asbestos is now known to be a hazardous pollutant. In 1971, the EPA identified asbestos as such, and in 1973, the Asbestos NESHAP was promulgated. Asbestos was one of the first hazardous air pollutants regulated under the air toxics program.

The health risks associated with asbestos exposure are significant. Inhaling asbestos fibres can cause them to become lodged deep within the lungs, where they may never be removed. This can lead to lung cancer, mesothelioma, and asbestosis. The risk of developing these conditions depends on the amount inhaled, the duration of exposure, and whether the individual has a history of smoking.

To minimise the release of asbestos fibres, the EPA's air toxics regulations specify work practices to be followed during the demolition and renovation of structures, installations, and buildings. These practices include removing and adequately wetting all asbestos-containing materials, sealing them in leak-tight containers, and disposing of the waste as efficiently as possible.

Bacteria

Indoor air quality is crucial, as bacteria can be transmitted through the air and cause health issues. Ultraviolet lights are often installed in ductwork to reduce bacteria, mould spores, and viruses. Additionally, proper ventilation is essential to prevent the growth of bacteria and mould.

Overall, bacteria are a significant gaseous pollutant that can have detrimental effects on human health. Proper ventilation, ultraviolet lights, and the reduction of indoor air pollutants are crucial measures to mitigate the impact of bacterial gaseous pollutants.

Frequently asked questions