Strategies To Combat Indoor Air Pollution

Indoor air pollution is a serious issue, with levels of air pollutants often higher inside than out. This is due to chemicals released from consumer products, gas appliances, building materials, smoking, and furniture. To reduce indoor air pollution, it is important to identify and control the sources of pollution, increase ventilation, and use air-cleaning devices. Natural ventilation, such as opening windows, is an easy way to improve indoor air quality by reducing pollutants. Mechanical means of ventilation, such as outdoor air intakes associated with the heating, ventilation, and air conditioning (HVAC) system, can also be effective. In addition to ventilation, the use of air purifiers and filters can help to reduce impurities in the air. It is also recommended to minimize the use of strongly scented products and to store chemicals and cleaning products safely.

Ventilation and shading

Natural ventilation is a simple and cost-effective way to improve indoor air quality. By opening windows and doors, outdoor air is introduced, diluting indoor pollutants and reducing their concentration. This is particularly important during activities that generate high levels of pollutants, such as cooking, painting, or welding. Natural ventilation can also help moderate indoor temperatures, especially in homes without air-conditioning systems or during power outages.

Mechanical ventilation, on the other hand, involves the use of fans, air conditioners, and HVAC systems. Kitchen and bathroom exhaust fans help remove cooking fumes and steam, respectively, while local exhaust fans can be used during activities that produce pollutants, such as painting or welding. Window air conditioners, when used with the vent control open, increase the outdoor ventilation rate, improving air quality. Advanced HVAC systems may also include energy-efficient heat recovery ventilators, which bring in fresh outdoor air while recovering heat energy.

When considering ventilation, it is important to evaluate the presence of outdoor sources of pollutants, such as smoke or refuse. In such cases, mechanical ventilation may be preferred to avoid introducing additional contaminants through natural ventilation. Additionally, proper maintenance and cleaning of ventilation systems are crucial to ensure their effectiveness in improving indoor air quality.

Shading, particularly exterior shading devices, plays a role in reducing indoor air pollution by controlling the amount of solar radiation entering a building. This can be achieved through the use of horizontal overhangs, vertical overhangs, or vertical fins installed on the exterior of a building. By reducing the solar radiation, the cooling load on the building is decreased, reducing the need for space cooling, which contributes to carbon emissions. Shading, therefore, helps to improve indoor air quality by mitigating the impact of climate change and reducing the energy consumption associated with space cooling.

Source control

Avoid Burning Indoors

Fires, candles, and incense release pollutants into the air. Kerosene heaters, camp stoves, and other unvented fuel-burning appliances emit toxic gases. It is best to avoid these sources of indoor air pollution. Opt for electric alternatives or use proper ventilation if these devices are necessary.

Go Fragrance-Free

Air fresheners, scented candles, and other strongly scented products often contain volatile organic compounds (VOCs) and other harmful chemicals. These can contribute to indoor air pollution and trigger respiratory issues like asthma. Choose fragrance-free options or natural alternatives to improve indoor air quality.

Improve Ventilation

Increase natural ventilation by opening windows and doors, especially during activities that generate high levels of pollutants, such as cooking, painting, or welding. Mechanical ventilation, such as exhaust fans in kitchens and bathrooms, can also help remove pollutants directly from the source. If possible, install a whole-house ventilation system or an energy-efficient heat recovery ventilator to bring in outdoor air and improve indoor air quality.

Seal or Enclose Certain Materials

Some sources of indoor air pollution, such as asbestos, can be sealed or enclosed to prevent the release of pollutants. Consult professionals for guidance on properly managing and containing such materials.

Adjust Appliances

Appliances like gas stoves can be adjusted to decrease emissions and reduce their impact on indoor air quality. Follow manufacturer instructions and guidelines to ensure proper use and maintenance of these appliances.

Choose Clean Energy Devices

Transition to clean household energy devices and fuels for cooking, heating, and lighting. This includes adopting cleaner technologies, such as induction cooktops, heat pumps, or solar panels, and choosing cleaner fuels, such as electricity or renewable energy sources, over polluting options like wood or coal.

Clean household energy

Cleaner technologies and fuels

One strategy to reduce indoor air pollution is to introduce cleaner technologies and fuels for cooking, heating, and lighting. This includes the use of solar, electric, biogas, liquefied petroleum gas (LPG), and alcohol (e.g. ethanol) as alternative energy sources. These technologies are considered clean for health at the point of use. For example, solar stoves can be used for cooking in areas with ample sunlight, and photovoltaic solar or wind energy can power electrical lights and small appliances. Rooftop thermal solar panels can also be used to heat water for bathing, kitchen sanitation, and filling hot water radiators.

Improved biomass stoves

While unprocessed coal and kerosene are major sources of health-damaging pollutants, improved biomass stoves can serve as an important transitional technology. Low-emission biomass stoves with features such as secondary combustion, insulated combustion chambers, and/or fans can improve combustion efficiency and significantly lower emissions. These stoves are considered clean if they meet tier 4 or 5 standards for PM2.5 and tier 5 standards for CO.

Ventilation and air purification

Another strategy to reduce indoor air pollution is to improve ventilation and air purification. Natural ventilation through open windows and doors can help reduce indoor pollutants and moderate indoor air temperature. Advanced home designs are also incorporating mechanical systems that bring outdoor air inside, such as energy-efficient heat recovery ventilators. Additionally, air purifiers can help reduce allergens and pollutants, especially benefiting those with asthma or allergies.

Behavioural changes and government policies

Transitioning to clean household energy also requires behavioural changes related to social and cultural practices. Conditional cash transfers can be used to incentivize households to adopt clean energy sources. Educational programs and supportive government policies are also crucial to promoting the sustained use of cleaner and more affordable home cooking technologies and fuels.

Natural ventilation

In addition to opening windows and doors, you can use window or attic fans to increase airflow. Local bathroom or kitchen fans that exhaust outdoors can also help remove contaminants directly from the room and improve ventilation. It is important to use these fans when engaging in activities that produce high levels of pollutants, such as cooking in the kitchen, which can produce fumes, or taking a hot shower in the bathroom, which can increase humidity levels.

While natural ventilation is a great way to improve indoor air quality, it is not always the most effective solution. In some cases, outdoor air can also be polluted, especially if you live near a busy freeway or a factory. In these situations, bringing in outdoor air through natural ventilation may not be the best option, and mechanical ventilation systems or air cleaners may be more suitable. Additionally, natural ventilation may not be sufficient for very high levels of indoor air pollution, and source control or air cleaning may be necessary.

Overall, natural ventilation is a simple and cost-effective way to improve indoor air quality by reducing indoor pollutants and increasing the amount of fresh outdoor air. It is important to be mindful of outdoor pollution sources and to pair natural ventilation with other strategies, such as source control and air cleaning, to ensure the most effective improvement in indoor air quality.

Air purifiers

There are several types of air purifiers available on the market, each with its own advantages and disadvantages. The three main types of portable air purifiers are filtered air purifiers, electrostatic air purifiers, and UV light air purifiers. Filtered air purifiers capture and trap airborne pollutants in one or more filters. They are considered the safest type for home use as they do not emit ozone or other potential pollutants. Electrostatic air purifiers create charged particles to trap pollutants in a filter, while UV light air purifiers use UV light to target certain contaminants such as viruses and bacteria. However, electronic air purifiers, including electrostatic and UV light air purifiers, can produce ozone and other harmful by-products.

High-efficiency particulate air (HEPA) filters are another popular option for air purifiers. They are effective in removing various pollutants, including mould spores, pet dander, dust mites, and tobacco smoke. HEPA filters can capture 99.97% of airborne particles that are 0.3 microns or larger. However, they are generally ineffective against volatile organic compounds (VOCs). Some air purifiers with HEPA filters have also been found to deliver "cleaned" air that contains additional VOCs and other harmful by-products. Therefore, it is important to carefully check the specific product packaging or labelling to ensure it is designed to filter the pollutants you are targeting.

When choosing an air purifier, it is important to consider the size of the room and the Clean Air Delivery Rate (CADR) rating. The CADR indicates the unit's ability to clean the air in a given space and can be determined by dividing the room's square footage by 1.55. Additionally, air purifiers with bipolar ionization (BPI) can emit ozone and other free radicals, so it is recommended to opt for filtering air cleaners that do not emit ozone.

Some highly regarded air purifier models include the Coway Mighty, Winix 5500-2, Blue Pure 511, and PuroAir's 240 and 400. These models offer competitive pricing and excellent performance against particulate pollution. The Coway Mighty, in particular, is known for its low operating costs, energy efficiency, and ability to handle air-quality emergencies, such as wildfires.

Frequently asked questions