Purifying Indoor Air: Can We Breathe Easy?

Indoor air pollution is a serious threat to human health, causing millions of deaths each year. It is caused by a plethora of pollutants, including carbon monoxide, volatile organic compounds, particulate matter, radon, and biological pollutants. These pollutants can be generated inside homes or buildings through occupants' activities, such as cooking, smoking, use of electronic machines, use of consumer products, or emission from building materials.

The first step in removing indoor air pollution is to identify the source of the pollution. This can include activities such as cooking, smoking, or the use of certain household products. Once the source of the pollution has been identified, there are several ways to reduce or eliminate it.

One way to reduce indoor air pollution is by improving ventilation. Proper ventilation helps remove polluted indoor air and replace it with fresh, clean air from outside. Opening windows, using exhaust fans, and ensuring proper ventilation in kitchens and bathrooms can all help to improve indoor air quality.

Another way to reduce indoor air pollution is by using air cleaners and filtration systems. These systems can help to remove pollutants such as mould spores, pet dander, dust mites, and tobacco smoke. High-efficiency particulate air (HEPA) filters are particularly effective, removing up to 99.97% of airborne particles.

In addition to improving ventilation and using air cleaners, it is important to address the source of the pollution. This may involve simple measures such as banning smoking indoors, giving pets regular baths, and using natural cleaning products instead of conventional cleaning products, which can contain harmful chemicals.

By following these steps, it is possible to significantly reduce indoor air pollution and create healthier indoor spaces.

Source control: Eliminate or reduce the source of indoor air pollution

To eliminate or reduce the source of indoor air pollution, it is important to first identify the sources of pollution. Some sources of indoor air pollution are obvious, detectable by smell, while others go unnoticed. Common sources of indoor air pollution include cigarette smoke, cooking fumes, pet dander, mould, and various cleaning products.

Ban Smoking

Cigarette smoke is one of the most common and dangerous indoor air pollutants. It contains over 7,000 chemicals, including at least 70 carcinogens, which can cause severe respiratory issues and other serious health consequences. It is crucial to implement a strict no-smoking policy indoors to protect the health of all occupants.

Improve Ventilation in the Kitchen

Cooking fumes can release harmful pollutants, including fine particulate matter and carbon monoxide. Ensure that your kitchen is equipped with an exhaust fan to effectively remove these fumes. Additionally, consider using natural ventilation by opening windows and doors when cooking to promote the circulation of fresh air.

Bathe Pets Regularly and Wash Their Bedding

Pet dander is another significant source of indoor air pollution, as it can trigger respiratory issues such as asthma and allergies. Maintaining good hygiene for your pets by regularly bathing them and washing their bedding can help minimise the presence of dander in the air.

Choose Natural Cleaning Products

Conventional cleaning products often contain harmful chemicals that contribute to indoor air pollution. Opt for natural, eco-friendly alternatives made with ingredients like white vinegar, baking soda, borax, citrus fruits, and essential oils. These natural products are safe for indoor use and effectively remove dirt and grime without releasing toxic fumes.

Keep Indoor Spaces Clean and Dry

Mould thrives in damp and humid environments and can cause respiratory infections, asthma, and allergies. To prevent mould growth, maintain a clean and dry indoor environment, especially in areas like the kitchen and bathroom, which are more prone to moisture. Regularly check for leaks or water damage and address them promptly to inhibit mould growth.

Store Chemicals Safely

Solvents, glues, and pesticides can release toxic fumes and pollute indoor air. Store these chemicals away from living areas to minimise their impact on indoor air quality. Additionally, consider using homemade cleaning products, such as a mixture of white vinegar and water, to reduce the use of potentially harmful chemicals.

Ventilation: Dilute indoor pollution with outdoor air

Ventilation is a crucial step in improving indoor air quality and diluting indoor pollution with outdoor air. Here are some ways to achieve effective ventilation:

Natural Ventilation

Opening windows and doors is a simple yet effective way to promote natural ventilation and encourage a healthy exchange of indoor and outdoor air. This method is especially useful when the weather is mild, and pollen counts are low. Natural ventilation can also be enhanced by window shading, such as closing the blinds to block direct sunlight.

Mechanical Ventilation

Most home heating and cooling systems, including forced-air heating systems, do not mechanically bring in fresh outdoor air. However, advanced designs for new homes are starting to incorporate mechanical systems that introduce outdoor air. These systems may include energy-efficient heat recovery ventilators, which help mitigate the cost of heating and cooling. Local exhaust fans in kitchens and bathrooms also play a vital role in removing contaminants and increasing the outdoor air ventilation rate.

Infiltration

Infiltration is the process by which outdoor air enters a home through small openings, joints, and cracks in walls, floors, and ceilings, as well as around windows and doors. While some level of infiltration occurs in all homes, it is important to ensure that the amount of outdoor air entering the home is sufficient to dilute indoor pollutants.

Other Considerations

When increasing ventilation, it is important to carefully evaluate the presence of outdoor sources of pollutants, such as smoke or refuse, nearby. Additionally, certain activities, such as painting, cooking, or hobby activities, can generate high levels of pollutants. Therefore, it is recommended to take extra ventilation measures during these activities or opt to perform them outdoors when possible.

Air cleaning: Remove pollutants from the air with mechanical means

Air cleaning is one of the most effective ways to reduce indoor air pollution. It involves the use of mechanical means to remove pollutants from the air. Here are some methods and best practices for air cleaning:

Types of Air Cleaners

There are two main types of air cleaners: portable air cleaners and HVAC (heating, ventilation, and air conditioning) systems. Portable air cleaners are standalone units designed for single-room use, while HVAC systems are larger, whole-house solutions. Upgrading to a higher-efficiency HVAC filter, such as a MERV 13 or above, can significantly improve your home's air quality by capturing smaller particles.

Portable Air Cleaners

Portable air cleaners, also known as air purifiers, are effective at removing particulate matter and other airborne pollutants. Look for units with HEPA-rated filters, as they are the most effective at removing smaller particles. Place them in rooms where vulnerable occupants spend most of their time, such as the living room or bedroom. Close doors and windows to increase the unit's effectiveness.

HVAC Systems

HVAC systems typically use rectangular, one-inch-thick filters located in the return ducts. Upgrading to a higher-efficiency filter, such as a MERV 13 or above, can improve the system's ability to capture smaller particles. Duct-mounted air cleaners can also be installed in HVAC systems to provide filtered air throughout the home.

Filter Maintenance

Regularly maintaining and replacing filters is crucial for effective air cleaning. For portable air cleaners, follow the manufacturer's recommendations for filter replacement, which is typically every two months or when the filter appears dirty. For HVAC systems, filters should be replaced several times a year or as recommended by the manufacturer.

Other Considerations

When selecting an air cleaner, choose a model that is appropriately sized for the room, has low-cost replacement filters, and has a high CADR (Clean Air Delivery Rate). Additionally, avoid air cleaners that produce ozone, as they can have negative health effects.

Combining with Other Strategies

While air cleaning is effective, combining it with source control and proper ventilation is essential. Source control involves eliminating or reducing the sources of pollutants, such as dust or pet dander. Ventilation involves bringing in outdoor air to dilute indoor pollutants and reduce humidity. By combining these strategies, you can significantly improve indoor air quality and create healthier living spaces.

Air purification: Use technology to filter and purify indoor air

Air purifiers are devices that remove contaminants from the air in a room to improve indoor air quality. They are commonly marketed as being beneficial to allergy sufferers and asthmatics, and at reducing or eliminating second-hand tobacco smoke.

There are two types of air purifying technologies: active and passive. Active air purifiers release negatively charged ions into the air, causing pollutants to stick to surfaces. Passive air purification units use air filters to remove pollutants. Passive purifiers are more efficient since all the dust and particulate matter is permanently removed from the air and collected in the filters.

HEPA filters

High-efficiency particulate air (HEPA) filters are highly efficient air filters that remove at least 99.97% of 0.3-micrometer particles and are usually more effective at removing larger and smaller particles. HEPA purifiers filter all the air going into a clean room and are arranged so that no air bypasses the HEPA filter.

Ultraviolet germicidal irradiation (UVGI)

Ultraviolet germicidal irradiation is a type of air purification technology that uses ultraviolet light to sterilize the air and remove microorganisms such as bacteria and viruses.

Activated carbon

Activated carbon is a porous material that can adsorb volatile chemicals on a molecular basis but does not remove larger particles. It is usually used in conjunction with other filter technologies, such as HEPA filters.

Photocatalytic oxidation (PCO)

Photocatalytic oxidation is an emerging technology in the HVAC industry that uses short-wave ultraviolet light to energize a catalyst (usually titanium dioxide) and oxidize bacteria and viruses.

Ionizer purifiers

Ionizer purifiers use charged electrical surfaces or needles to generate electrically charged air or gas ions. These ions attach to airborne particles, which are then attracted to a charged collector plate. This process produces trace amounts of ozone and other oxidants as by-products.

Plasma air purifiers

Plasma air purifiers are a form of ionizing air purifier that destroys volatile organic compounds, bacteria, and viruses by chemical reactions with generated ions.

Ozone generators

Ozone generators are designed to produce ozone, a strong oxidant gas that can oxidize many other chemicals. However, it is not healthy to breathe ozone gas, and ozone generators should only be used in unoccupied rooms.

Thermodynamic sterilization (TSS)

Thermodynamic sterilization uses heat sterilization to incinerate microbiological particles such as bacteria, viruses, dust mite allergens, and mold and fungus spores. The air is passed through a ceramic core heated to 200 °C (392 °F) and then cooled before being released.

Reactive Oxygen Species (ROS) Technology

Reactive Oxygen Species (ROS) Technology uses long-lived ROS such as Hydrogen Peroxide and low levels of Ozone to kill pathogens, including mold, bacteria, viruses, and germs in the air and on surfaces.

Other considerations

When choosing an air purifier, it is important to consider factors such as the Clean Air Delivery Rate, efficient area coverage, air changes per hour, energy usage, and the cost of replacement filters. It is also important to ensure that the purifier is the right size for the room and has a high CADR rating, which indicates its ability to clean the air in a given space.

Smart homes: Use smart sensor technology to monitor and improve indoor air quality

Smart homes can harness smart sensor technology to monitor and improve indoor air quality. Here are some ways this can be achieved:

Source Control

The first step in improving indoor air quality is to identify and eliminate the source of pollution. Common indoor air pollutants include cigarette smoke, pet dander, cooking fumes, dust, and volatile organic compounds (VOCs) from cleaning products. By removing or reducing these sources, you can significantly improve the air quality in your home.

Ventilation

Smart sensors can be used to monitor the indoor air quality and trigger ventilation systems when needed. Proper ventilation is crucial in diluting indoor pollutants and reducing humidity, which can lead to the growth of mould and mildew. Smart sensors can detect high levels of pollutants or humidity and activate fans, open windows, or turn on the air conditioning to bring in fresh outdoor air.

Air Purification

In addition to ventilation, air purification systems can be used to remove pollutants from the air. High-efficiency particulate air (HEPA) filters are particularly effective at removing mould spores, pet dander, dust mites, and tobacco smoke. Smart sensors can monitor the indoor air quality and adjust the settings of air purifiers accordingly, ensuring that the air is continuously cleaned.

Smart Alerts and Notifications

Smart sensors can be integrated with home automation systems to provide alerts and notifications when indoor air quality deteriorates. For example, if the sensor detects high levels of carbon monoxide or VOCs, it can send an alert to the homeowner's smartphone, allowing them to take immediate action, such as opening windows or turning on air purifiers.

Data-Driven Decisions

Smart sensors collect real-time data on indoor air quality, which can be analysed to identify patterns and trends. For example, sensors may detect higher levels of pollutants during rush hour due to increased traffic. This data can be used to make informed decisions about ventilation and purification strategies, as well as identify areas where additional measures may be needed, such as installing additional air purifiers or improving insulation.

Integration with Other Smart Home Devices

Smart sensors can also work in conjunction with other smart home devices to improve indoor air quality. For example, if a smart sensor detects high levels of particulate matter in the kitchen during cooking, it can automatically turn on the range hood or exhaust fan to remove fumes and odours. Similarly, if high levels of humidity are detected, the system can activate a dehumidifier to prevent the growth of mould and mildew.

Frequently asked questions