Converting Polluted Air: Fresh Solutions For Cleaner Breathing

Air pollution is a major environmental health risk, especially for children, and can have serious and sometimes fatal consequences. It is caused by a variety of factors, including vehicle emissions, domestic heating, road transport, energy production, waste, cleaning products, paints, and natural occurrences such as drought and wildfires. To combat this issue and convert polluted air into fresh air, various methods can be employed, including improving ventilation, using air purification systems, advocating for policy changes, and adopting more sustainable practices in our daily lives.

Characteristics and Values of Converting Polluted Air into Fresh Air

Using microalgae to absorb carbon dioxide and release oxygen

Microalgae are a promising natural solution to help convert polluted air into fresh air. They are abundantly available in the natural environment, thanks to their ability to survive and grow rapidly under harsh and inhospitable conditions.

Microalgae can absorb carbon dioxide and release oxygen during photosynthesis. This process, called carbon dioxide sequestration, is critical to resolving the climate change crisis. The efficiency of photosynthesis in microalgae is 10–20% higher than in plants, and microalgae contribute up to 60% of the oxygen content in the Earth's atmosphere.

Microalgae can be autotrophic or heterotrophic, depending on their nutritional requirements and mode of growth. Autotrophic microalgae perform photosynthesis as their main metabolic process, using sunlight as an energy source and atmospheric CO2 as a carbon source. Heterotrophic microalgae, on the other hand, require an organic carbon source and can be grown in the absence of light since photosynthesis does not occur in this group. A third category, mixotrophic algae, can undergo photosynthesis and also assimilate exogenous organic carbon.

The use of microalgae technology enables a circular carbon economy by linking carbon dioxide mitigation and bioenergy production. Microalgae can directly capture emitted CO2 from the atmosphere, addressing the significant problem of excessive CO2 emissions. For example, a study found that a species of microalgae, Chlorella vulgaris, had a maximum rate of absorption of CO2 of 0.412 g/L·day and could utilize up to 8.125 L of CO2 in one day.

Additionally, microalgal cultivation is environmentally friendly as the biomass can be utilized for various purposes, such as the production of biofuels, food and feed supplements, pharmaceuticals, nutraceuticals, and cosmetics. Microalgae can also be used for wastewater treatment, efficiently removing nitrogen, phosphorus, and dissolved oxygen.

Improving ventilation at home with HRV and ERV systems

Improving ventilation is an important step towards converting polluted air into fresh air at home. While natural ventilation through open windows and doors is a simple method, mechanical ventilation systems like HRV and ERV are more effective in improving indoor air quality.

HRV Systems

HRV stands for Heat Recovery Ventilation, also known as Mechanical Ventilation Heat Recovery (MVHR). It is a ventilation system that recovers energy by operating between two air sources at different temperatures. It reduces heating and cooling demands by recovering residual heat from the exhaust gas and using it to preheat or precool the fresh air introduced into the air conditioning system. HRV systems are ideal for homes in colder climates as they retain heat and moisture indoors. They typically recover about 60-95% of the heat in the exhaust air, significantly improving energy efficiency.

ERV Systems

ERV stands for Energy Recovery Ventilation. It is similar to HRV but also transfers humidity from the stale air to the fresh air. ERV systems are perfect for homes in warmer, humid climates with mild winters. They help maintain indoor relative humidity and improve indoor air quality. ERV units use the exhaust air to precondition the supply air by employing a heat exchanger that also recovers the humidity of the air. ERV systems can achieve thermal efficiency of up to 80% while reducing energy consumption.

Choosing Between HRV and ERV

The choice between HRV and ERV systems depends on the climate and specific needs of your home. If you live in a colder region, HRV is a better option as it retains heat more effectively. On the other hand, ERV is ideal for warmer, humid climates as it helps regulate humidity levels. Additionally, consider the construction of your home. Tight construction and insulation can lead to stale and stuffy air, making ERV a suitable choice.

Other Ventilation Tips

While HRV and ERV systems are effective, combining them with other methods can further improve indoor air quality. Regularly opening windows, especially during cleaning, helps ventilate your home. Houseplants are also natural air purifiers, absorbing common volatile organic compounds and improving indoor air quality. Finally, ensure proper ventilation in the kitchen and when using appliances that release pollutants, such as gas stoves, to minimize indoor air pollution.

Reducing vehicle emissions by refuelling during cooler hours

One way to convert polluted air into fresh air is by reducing vehicle emissions. Vehicle pollutants are harmful to our health and contain greenhouse gases that cause climate change. Burning gasoline and diesel fuel creates harmful byproducts like nitrogen dioxide, carbon monoxide, hydrocarbons, benzene, and formaldehyde.

One way to reduce vehicle emissions is by refuelling during cooler hours. In the summer, refuelling vehicles in the early or late hours of the day, when temperatures are lower, helps reduce air pollution. This is because lower temperatures lead to less evaporation of the fuel, resulting in fewer harmful vapours being released into the air.

Additionally, maintaining your vehicle is important. Newer vehicles have complex emission controls to keep them running as cleanly as possible. If any of these controls are not functioning properly, your vehicle will pollute more. Regularly checking your vehicle's engine light and keeping up with repairs and maintenance can help ensure it is running as efficiently as possible.

Another way to reduce emissions is to drive more efficiently. This includes reducing idling, which can expose children to diesel exhaust and increase greenhouse gas emissions. Turning off your engine when possible, such as when waiting in a parking lot or picking someone up, can help reduce emissions and save fuel.

Finally, consider other transportation options. Reducing the number of miles driven means fewer emissions. Whenever possible, try walking, biking, or taking public transportation like the bus or train. If public transportation is not an option, carpooling with someone who lives nearby can also help reduce vehicle emissions.

Using air cleaners and air purifiers to reduce indoor pollutants

The air inside your home can be highly polluted, which can have a serious impact on your health. Common indoor pollutants include volatile organic compounds (VOCs), radon, asbestos, mould, bacteria, dust, pollen, and pet dander. To improve indoor air quality, it is essential to first reduce or remove the sources of these pollutants and ventilate with clean outdoor air.

One way to reduce indoor pollutants is by using air cleaners and air purifiers. Air cleaners are devices that use fans and filters to circulate and clean the air. They can capture particles such as dust, pollen, and pet dander, as well as some bacteria and viruses. However, it's important to note that not all air cleaners can remove all types of pollutants, and their effectiveness depends on the model. Mechanical room ventilation systems, such as HRV (Heat Recovery Ventilation) and ERV (Energy Recovery Ventilation), can also be installed in your home to improve indoor air quality. These systems bring in fresh outdoor air while removing stagnant air and can even help regulate temperature and humidity levels.

Portable air cleaners, also known as air purifiers or air sanitizers, are designed to filter the air in a single room or area. They can be particularly useful for vulnerable individuals, such as those with respiratory or cardiovascular issues, by removing particulate matter and other airborne pollutants. Studies have shown modest health improvements in individuals who consistently use mechanical, portable air cleaners. When choosing a portable air cleaner, look for one with a HEPA-rated filter, as these are the most effective at trapping particles. For sensitive individuals or difficult-to-remove odours, a charcoal filter can be added to the air cleaner.

In addition to portable air cleaners, you can also improve indoor air quality by upgrading the air filters in your furnace or central heating, ventilation, and air-conditioning (HVAC) system. HVAC filters are designed to filter the air throughout your entire home. Duct-mounted air cleaners can be installed into a central HVAC system to provide filtered air throughout the home. It is important to properly maintain your HVAC system and regularly replace the filters to ensure optimal performance.

While air cleaners and purifiers can be effective tools for reducing indoor pollutants, they should not be solely relied upon. The most effective approach is to combine source control, ventilation, and filtration methods. Additionally, when using air cleaners, ensure that the air ducts and filters are regularly cleaned, as they can gather dust and pollutants over time, reducing their effectiveness.

Planting trees to filter pollutants and absorb carbon dioxide

Trees are a natural solution to improving air quality and can be used to filter pollutants and absorb carbon dioxide. They act as physical barriers that block pollutants from reaching people, and their leaves absorb carbon dioxide and other harmful gases from the air. Trees also release oxygen into the atmosphere through photosynthesis, a process that converts carbon dioxide and water from the air into chemical compounds that the tree consumes as food.

The tiny pores on the leaves of trees, called stomata, inhale air that contains toxic pollutants. Gases, including pollutants such as SO2, NO2, CO, and ozone, are absorbed and broken down within the inner surfaces of the leaves. Trees also remove particulate matter from the air by temporarily "catching" it on their vegetative surfaces. When it rains, these particulates are washed off the tree and carried into the soil or dissolved into stormwater.

According to the US National Park Service, planting trees helps improve air quality through three key impacts: altering the concentration of pollutants, reducing air temperatures, and releasing clean oxygen for us to breathe. In the contiguous United States, urban trees remove an estimated 711,000 metric tons of air pollution annually. Globally, forests may absorb and store as much as 30% of carbon emissions from human activities.

However, it is important to note that trees alone are not a magic solution to the world's carbon dioxide challenge. Climate change can make trees more susceptible to insect and disease damage, reducing their ability to sequester carbon. To effectively address carbon emissions, tree-planting initiatives must be combined with other solutions and mitigation efforts, such as technological solutions like direct air capture and permanent storage.

Frequently asked questions