Media Q&A

What are the harmful pollutants and how are they measured?

Particulate pollution is measured in micro grams per cubic metre (µg/m³). There are three standards of PMs. PM1, PM2.5 and PM10. These denote the size of the particles and are measured in microns. The World Health Organisation (WHO) guidance does not specify a safe limit for particulate matter but, considering natural background levels and available technology, it sets targets of 25 µg/m³ for PM2.5 and 50 µg/m³ for PM10 as 24-hour averages.

For annual average exposures the WHO sets targets of 10 µg/m3 for PM2.5 and 20 µg/m3 for PM10.

The main Gas phase pollutants are:

  • Nitrogen Dioxide (NO₂) – is a toxic gas which causes significant inflammation of the airways. NO₂ is the main source of nitrate aerosols which form an important fraction of PM2.5 and, in the presence of UV light, of ozone. The major sources of anthropogenic emissions of NO2 are combustion processes (heating, power generation, and engines in vehicles and ships).
  • Sulphur Dioxide (SO₂) – is a colourless gas with a sharp odour. It is produced from the burning of fossil fuels (coal and oil) and the smelting of mineral ores that contain sulphur. The main anthropogenic source of SO2 is the burning of sulphur-containing fossil fuels for domestic heating, power generation and motor vehicles.
  • Ground level Ozone (O₃) – not to be confused with the ozone layer in the upper atmosphere – this is one of the major constituents of photochemical smog. It is formed by the reaction with sunlight (photochemical reaction) of pollutants such as nitrogen oxides (NOx) from vehicle and industry emissions and volatile organic compounds (VOCs) emitted by vehicles, solvents and industry.

These pollutants are measured in µg/m³ or parts per million (ppm) or parts per billion (ppb). WHO safe levels are (in µg/m³):

• 40 for NO₂,
• 20 for SO₂
• 100 for O₃

Reduced Sulphur Compounds – such as Hydrogen Sulphide (H2S) and Methanethiol (CH3SH) are harmful and often emitted by landfill and water treatment works. Even though the concentrations are typically low the powerful odour can have a significant impact on local populations.

What is Evergen’s technology?

Evergen has two proprietary technologies:

PureAire – utilises a technique called Active Ionisation to remove pollutants from air. This is coupled with advanced airflow engineering for outdoor applications. PureAire systems are patented and tested and certified by a number of organisations in EU and India as highly efficient at removing airborne pollutants and bacteria. They are designed to be integrated into a variety of new and existing street furniture and city infrastructure to vastly improve air quality inside and outside of buildings.

Excigen – invented by scientists at the University of Copenhagen Dept. of Atmospheric Chemistry, this patented technology is a chemical process based on a reactive species of ozone which is used to clean a polluted airstream. The system can be connected directly to exhaust chimneys of industrial plants or HVAC systems. Excigen technology is low cost, highly scalable and can be adapted to treat a wide variety of industrial pollutants and odours. Excigen solution is planned to be launched later in 2019.

What is the cost of Evergen technology?

PureAire systems have to be “sized” according to the area volume to be cleaned, so it is difficult to quote a price without knowing the outdoor space or indoor area you want to clean.

Price depends on a number of parameters, for instance the size of the area to be cleaned, the airflow required and the type and amount of pollution to be removed. Before Evergen can provide accurate quotes the engineers have to undertake a technical survey which takes into account the volume of air to be cleaned, the number of times the air will be changed, the current pollution levels and the target air quality.

What is the main USP for Evergen technology?

PureAire technology is far superior to the traditional paper filters such as HEPA (High Efficiency Particle Absorption) which are currently found in residential and commercial air cleaners. Air purifiers based on PureAire technology are extremely low power consumption and – as there are no filters to replace – are almost zero maintenance. Furthermore, there is no degradation of performance as there is no filter that can get blocked and impede air flow. PureAire is also environmentally friendly as there is no filter to be recycled

EXCIGEN – whilst current technologies can remove some pollutants from exhaust gases, they are not applicable to all ranges of pollution concentrations, airflow and temperatures. Excigen technology is extremely efficient and can be “tuned” to neutralise pollutants and odours from a wide variety of industrial processes. The technology is extremely scalable and low operating cost.

Are Evergen systems already commercially available?

PureAire systems are in production and available now. The first units have been installed in India and at schools in London. Systems are developed to clean air in homes, commercial buildings like offices, hotels, hospitals and shopping malls; as well as systems that can be integrated into street furniture and city infrastructure such as bus shelters and small outdoor areas like school playgrounds, courtyards and outdoor markets.

Systems based on Excigen technology are under development and Evergen expects to announce the first marketable products later in 2019.

What is the ISO16890 standard?

The new global standard UNI EN ISO 16890 classifies air filters on the basis of their ability to retain the dispersed airborne particulate matter (PM10, PM2,5 and PM1). It is creating a revolution in the air filtration sector. It replaces the twenty year old previous and obsolete EN 779:2012 standard (F7, F8, F9), anti-dust air filters for general ventilation. The air cleaner efficiency refers to the particle size of the PM particles and involves testing over long periods. So far very few companies have attained this standard.

What is Evergen’s plan for outdoor air cleaning?

Evergen’s PureAire technology can be integrated into a variety of new and existing street furniture and City infrastructure. The company is designing air handlers for installing PureAire cleaners into bus shelters. As shown from NPLI testing as well as providing clean air within the bust shelter Evergen can provide better air quality around the bus shelter too. At the same time the Evergen scientists are studying outdoor markets such as Khan Market and Galleria in Delhi, which currently have very poor air quality.

What about indoor air cleaning?

Actually this is very important as people spend between 80-90% of time indoors. Whether it’s in homes, workplaces, schools, places of worship or recreational places like gyms and shopping malls, this is the first place society should look at cleaning air. PureAire systems can reduce people’s exposure to polluted air by 80-90% of the time. Evergen has solutions for residential and commercial applications as well as proven solutions for hygiene and anti-bacterial in commercial kitchens and hospital environments.

As PureAire purifiers do not use filters, there is no filter to get blocked up or replace. Periodic maintenance involves sliding out the collector cell and washing it to remove the dust particles So PureAire systems are virtually maintenance free. Another major advantage is PureAire systems are significantly environmentally friendly as there are or no filters to dispose of.

How is the dust and dirt disposed of?

This depends on whether the air cleaner is used in a residential or commercial environment. In residential applications the PMs in the collector box can be simply disposed of like the debris from a vacuum cleaner. In commercial installations the collector plate is removed from the air cleaner and this is taken back to the service centre where the dust is removed in a controlled environment. This usually involves washing the collector plate and disposing of the debris as per the prevailing regulations. In the long term Evegen plans to actually weigh the amount of PMs collected by each individual collector plate so it will be know how much pollution was removed from each particular location. This data will be shared with the clients.

Where are Evergen’s manufacturing facilities?

Currently PureAire systems are manufactured in EU and are built to ISO16890 standards. This is the latest international standard for air cleaners. The plan is to set up manufacturing in India and UK as soon as possible. This will happen in second half of 2020. Evergen is also planning to develop Excigen solutions in India so they will be tailored to clean the local Industrial pollutants.

Why did Evergen choose to launch in India?

Evergen needs to test and validate its technique for cleaning outdoor air. Working with scientists from University of Copenhagen the Evergen team decided to do this in one of the Worlds most polluted cities – Delhi. The team set up its pilot at the end of May 2018 in an open area in Central Delhi. The pilot was constructed using a combination of high efficiency air cleaners coupled with advanced airflow engineering. Air quality was monitored using high precision monitors over a period of two weeks. Once the scientists had collected sufficient data, Evergen held a media event to demonstrate the technology and announce the results to press, politicians and public. On the day of the launch Delhi experienced a “pollution episode” and ambient air quality was 500-800. However NDTV, India’s premier news channel reported air pollution at our pilot to be consistently below 30.

Why did you have Evergen technology solution tested?

Evergen’s outdoor CleanAirZone was the first successful demonstration of outdoor air cleaning at street level. Previously a number of ideas and techniques for cleaning outdoor air had been attempted in India and had all failed. So Evergen felt it was most important that its solution should be independently tested and validated so there is no doubt about the performance.

Why did you choose NPLI?

The National Physical Laboratory of India is one of World’s foremost measurement and standards institutes. NPLI India ranks amongst the World’s top 5 such organisations. There is no other organisation better qualified to accurately test and measure air quality. Measurements by NPLI are above question.

What about testing by Delhi Pollution Control Board (DPCB) or Central Pollution Control Board (CPCB)?

These organisations are not involved in testing and validating third party air cleaning technologies. That is not their role. Their primary focus is to continuously monitor ambient air quality.

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