Trends in air purification devices

In 2018 the World Health Organisation (WHO) estimated that nearly 7 million people die every year due to inhaling the fine particles in polluted air. Such pollution causes one-third of deaths from strokes, lung cancer and heart disease and can also lead to chronic obstructive pulmonary diseases and respiratory infections. It is equivalent to smoking and is much worse for health than a high salt intake. Further, the WHO estimated that almost 700,000 children die each year from the effects of air pollution.

There is an urgent need to address this issue. Vehicles and factories are two major contributors to air pollution as they burn fossil fuels. It is no surprise that air pollution is closely linked to climate change, thus it is also a key factor in the Earth’s rising temperature.

Air purifiers eliminate health hazards caused by poor air quality by removing contaminants, including tobacco smoke. Further, they are beneficial for people with allergies and asthma. It is estimated that the global air purifier market will increase by a compound annual growth rate of more than 32.4% between 2018 and 2024.

Origin of air purifiers

The very first air purifying apparatus was developed by Lewis P Haslett and patented in 1848. In the 1850s John Stenhouse used charcoal filters to clean the air, which led to the development of the masks used in London factories to protect workers from toxic gases. Almost a century later, the US Atomic Energy Commission invented the HEPA filter to clean air that had been contaminated by radioactive particles. After the Second World War, it was released to the public and is now used by air purifier companies as a heavy-duty filtration device.

Indoor air purifiers

In the 1960s a German engineer developed a simple air purifying system. It comprised a filter pad attached by magnets, which trapped dust in the air. This purifying system was the first that could be used within households. Further, it led to the discovery that air purifying systems helped to relieve the symptoms of asthma and allergies.

Air purifying technologies can be grouped into the following two categories:

• those with filters (eg, pre-filters and HEPA, activated carbon and permanent/washable filters); and
• filterless purifiers (eg, air ionisers, electrostatic precipitators, ozone generators, thermodynamic sterilisation, ultraviolet germicidal irradiation and photocatalytic oxidation (PCO) cleaners).

Today, the air purifier market is dominated by HEPA purifiers, which are expected to contribute significantly to the forecast growth period. Other technologies that are expected to experience growth are activated carbon and ozone-based purifiers.

Ultraviolet germicidal irradiation, HEPA filters, activated carbon and ioniser purifiers are the most common air purifiers for home and commercial use for helping those who suffer from asthma and allergies.

PCO cleaners are another emerging technology. They use UV light to react with a catalyst TiO2. The reaction oxidises bacteria, viruses, fungi, odours and volatile organic compounds and breaks the pollutants down into harmless carbon dioxide and water molecules.

The following are the major players in the air purifier market:

• Panasonic;
• Daikin Industries;
• Gree Electric Appliances;
• LG Electronics;
• Samsung Electronics;
• Sharp; and
• Samsung.

Patent filing trend

The very first air purifying apparatus was patented in 1848. This technology has continuously advanced since then. In 1998 an inventor worked with a team of engineers from Switzerland and Germany in order to make the most effective consumer air purifier in the world, which was the first air purifier for rooms – the IQAir HealthPro Plus. It was the most successful air purifying system for relieving asthma and allergy symptoms.

From 2012 onwards, patent filing in air purifying technology has taken a leap forward. From 2013 to 2016 there was a 350% increase in filings in comparison with previous four years.

The majority of the research in recent years has focused on the following challenges:

• improving activated carbon absorption;
• improving performance and reducing the cost of catalytic material;
• improving the removal of moisture content carried in the outdoor air during purification;
• improving the filter’s life to eliminate the difficulty of replacement and cost; 
• improving filter quality by reducing the size of the filter;
• eliminating bad odours; and
• reducing the amount of ozone and ions released during purification.

China filed for nearly 50% of patents, making it the major market for this technology, followed by Japan, Korea and the United States.

Comment

Air purifiers have undergone much R&D, from basic wearable devices to the advanced self-standing purifying systems that are used today. As air pollution levels rise, the need for air purifiers is bound to grow. It will be interesting to see further advancements in this technology.