Indoor Air Pollution: Activities To Watch Out For

Indoor air pollution is a severe issue, causing approximately 3.2 million deaths globally each year, including 237,000 children under five. It is caused by a range of human activities, including cooking, smoking, cleaning, and redecorating, as well as the use of inefficient and polluting fuels and technologies. Indoor air pollution is particularly harmful due to the prolonged exposure that people experience in their homes and workplaces. Pollutants can remain in the air long after activities have taken place, and inadequate ventilation can cause dangerous build-ups of pollutants.

Burning solid fuels

Inefficient combustion of solid fuels in poorly ventilated homes releases a range of harmful pollutants, including particulate matter, gases, and toxic metals. The emissions from burning solid fuels are comparable to those from tobacco smoke in terms of particulate matter and gases, posing similar adverse health effects. High levels of exposure to indoor smoke from solid fuels can increase the risk of respiratory and cardiovascular diseases, lung cancer, and acute lower respiratory tract infections (ALRIs), especially in children.

Particulate matter (PM) is a significant concern, with indoor PM levels often exceeding outdoor levels. The combustion of solid fuels releases fine and ultrafine particles that can penetrate deep into the lungs and enter the bloodstream. These particles can contain toxic substances such as sulfates, nitrates, endotoxins, polycyclic aromatic hydrocarbons, and heavy metals. Inadequate ventilation exacerbates the problem by not adequately removing indoor pollutants.

Interventions, such as improved biomass stoves, have been proposed to reduce exposure to indoor air pollution from solid fuel combustion. However, evaluations of these interventions have shown that the levels of PM reduction achieved are still insufficient to meet the WHO's air quality guidelines. The use of alternative clean fuels and technologies, as recommended by the WHO, is crucial to mitigating the health risks associated with burning solid fuels. These include solar, electricity, biogas, liquefied petroleum gas (LPG), natural gas, and alcohol fuels.

Additionally, the time and effort spent gathering, preparing, and using solid fuels for cooking and heating can constrain opportunities for health, development, and education, particularly in women and children who are typically responsible for these tasks. The ingestion of kerosene, commonly used for lighting, is also a leading cause of childhood poisonings. Thus, addressing indoor air pollution from burning solid fuels has far-reaching social and economic implications.

Poor ventilation

There are several ways in which poor ventilation contributes to indoor air pollution. Firstly, inadequate ventilation allows indoor pollutants to build up without sufficient airflow to dilute or remove them. This includes pollutants from indoor activities such as cooking, which emits millions of ultra-fine particles through the burning of oil, wood, and food. These particles can spread beyond the kitchen to other areas of a building. Smoking is another major source of indoor pollution, particularly fine particles known as PM2.5, which can have serious health impacts.

Secondly, poor ventilation can result in high humidity levels, which promote the growth of mold, bacteria, viruses, and dust mites, all of which can negatively affect human health. High humidity may be due to poor construction or inadequate air exchange, and it is often an issue in cooler climates where natural ventilation is limited during the winter months.

Additionally, outdoor air pollution can be drawn indoors through ventilation systems, particularly in buildings located near busy highways, industrial sites, or other sources of emissions. This highlights the importance of pairing ventilation with source control, such as reducing outdoor air pollution and preventing indoor activities that generate pollutants.

To improve indoor air quality, it is essential to address ventilation issues. This can be achieved through a combination of natural ventilation, such as opening windows, and mechanical ventilation, including the use of fans and exhaust systems. Exchanging indoor air with fresh outdoor air helps to dilute and remove pollutants, reducing the risk of health issues associated with poor indoor air quality.

Cooking with polluting fuels

The combustion of solid fuels emits dangerous particulate matter, carbon monoxide, and other toxic pollutants. Indoor air pollution levels from cooking can be up to 20 times higher than the WHO's air quality guidelines. High levels of indoor air pollution from cooking with wood or charcoal can result in the release of harmful pollutants such as carbon monoxide, formaldehyde, and other toxic chemicals. Cooking with these fuels can also generate unhealthy air pollutants from heating oil, fat, and other food ingredients, especially at high temperatures.

The use of polluting fuels for cooking disproportionately impacts women and children, who typically spend more time near the domestic hearth and are exposed to harmful smoke. In addition, the time and effort required to gather and prepare these fuels can limit educational and economic opportunities, particularly in low- and middle-income countries. The ingestion of kerosene, commonly used for cooking, is also the leading cause of childhood poisonings.

To address the issue of indoor air pollution from cooking with polluting fuels, organizations like the WHO and the U.S. Environmental Protection Agency (EPA) have developed guidelines and initiatives to promote the use of cleaner and more efficient cooking technologies and fuels. These include the adoption of solar, electricity, liquefied petroleum gas (LPG), natural gas, and improved biomass stoves that meet emission targets.

It is important to note that inadequate ventilation can exacerbate indoor air pollution levels. Properly installed range hoods, exhaust fans, and open windows can help improve ventilation and reduce the concentration of pollutants emitted during cooking. Additionally, regular inspection and maintenance of cooking appliances are crucial to ensure their safe and proper functioning, minimizing the release of harmful pollutants.

Smoking indoors

Particulate matter (PM) is one of the harmful components of ETS and is responsible for its substantial contribution to indoor air pollution levels. PM is defined as carbonaceous particles associated with adsorbed organic chemicals and reactive metals, with main components including sulfates, nitrates, endotoxins, polycyclic aromatic hydrocarbons, and heavy metals such as iron, nickel, copper, zinc, and vanadium. PM can be classified by particle size: coarse particles (PM10) with a diameter of less than 10 µm, fine particles (PM2.5) with a diameter of less than 2.5 µm, and ultrafine particles (PM0.1) with a diameter of less than 0.1 µm. PM is particularly concerning as it can be inhaled, affecting the lungs and heart and causing serious health issues. Research indicates that cooking and cigarette smoking are the largest sources of indoor air PM, with smoking being a major source of PM2.5. The concentration of PM2.5 is higher in the winter than in the summer, and homes with smokers can have estimated increases ranging from 25 to 45 µg/m3.

The only way to eliminate secondhand exposure to tobacco smoke is to prohibit smoking indoors, including in vehicles and near air intakes and entryways to enclosed spaces. Ventilation, filtration, and air cleaning techniques can reduce exposures but cannot eliminate them. Implementing smokefree policies in homes, schools, offices, and other enclosed spaces can significantly improve indoor air quality. It is recommended to smoke outdoors, away from indoor spaces and building air intakes, doors, open windows, and other enclosed spaces.

In addition to ETS, indoor smoking can also contribute to the presence of other pollutants, such as carbon monoxide and nitrogen dioxide, particularly if gas stoves or heaters are used. Inadequate ventilation can further increase indoor pollutant levels by not adequately diluting emissions from indoor sources and carrying indoor air pollutants out of the area. High temperature and humidity levels can also increase certain pollutant concentrations.

Using unclean appliances

The use of unclean appliances, particularly those that burn fuel, is a significant contributor to indoor air pollution. Fuel-burning appliances, such as cooking stoves, furnaces, and water heaters, emit harmful pollutants that can adversely affect human health and the environment. These emissions contain dangerous pollutants, including nitrogen oxides, carbon monoxide, particulate matter, and air toxics like formaldehyde. The lack of proper ventilation in indoor spaces exacerbates the problem, leading to higher concentrations of these pollutants.

The health risks associated with exposure to pollutants from unclean appliances are significant. Short-term exposure to indoor air pollutants may result in irritation of the eyes, nose, and throat, headaches, dizziness, and fatigue. More alarmingly, long-term exposure has been linked to severe health issues such as asthma, heart disease, stroke, lung cancer, type 2 diabetes, and an increased risk of respiratory infections. Children, pregnant individuals, and people with pre-existing lung diseases are especially vulnerable to the harmful effects of these pollutants.

To mitigate the risks associated with unclean appliances, it is essential to prioritize proper maintenance and ventilation. Ensuring that appliances are in proper working order and installing carbon monoxide detectors are crucial steps in reducing the potential for harmful emissions. Additionally, utilizing ventilation methods, such as stove range hoods that vent to the outside or simply opening windows during and after appliance use, can help dilute and remove pollutants from indoor spaces.

Transitioning to cleaner alternatives, such as electric cooking appliances, heat pumps, and modern stoves, is highly recommended by organizations like the American Lung Association. These alternatives offer safer and more environmentally friendly options that can significantly reduce the presence of harmful pollutants in indoor spaces. Government programs and incentives also exist to encourage homeowners to upgrade to newer, cleaner electric appliances, making it more accessible for families to make the switch to cleaner alternatives.

Taking proactive measures to maintain and properly ventilate existing unclean appliances, as well as transitioning to cleaner alternatives when possible, are essential steps in improving indoor air quality and safeguarding the health and well-being of those who occupy these spaces.

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