Air quality monitoring is about understanding the quality of our residential environment. This is of great importance to ensure our family and children are well protected. A good quality of the residential environment will make it more attractive and healthier to live, work and invest in. On the other hand, the degradation of the environment, through air pollution, climate change, etc., may have negative impacts on human health and well-being.

To understand the quality of our environment, the first step is to quantify the impact by monitoring and measuring it with the environmental sensing tools.

For example, to know the quality of the air, we measure the fine Particulate Matter 2.5 (PM2.5). If more than 35 ¦Ìg/m3 of PM2.5 is detected within a day, the air quality is deemed to be unhealthy for sensitive groups and we should avoid having outdoor activities for our family.

This comprehensive data will allow us to quickly analyze the quality of our residential environment and make prompt actions for short-term and long-term countermeasures.

Environmental indicators are a set of numerical values that track the state of the environment over a period of time. Examples of commonly used environmental indicators include rainfall, earth surface temperature, humidity, air particular matter (PM), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO).

Environmental indicators can be measured and reported at different scales. For example, a city may track the air quality along with the water quality and count the number of rare species of birds to estimate the health of the environment in their area. In another scenario, people living in hilly residential areas may track the variations in rainfall patterns and its impact on slope stability and soil erosion.

Air pollutants with the strongest evidence for public health concern are particulate matter (PM), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO).

Both short and long-term exposure to ambient air pollution can lead to reduced lung function, respiratory infections and aggravated asthma. According to reports from the World Health Organization (WHO), air pollution is the cause of over 34% of deaths from stroke, lung cancer, and chronic respiratory disease, and 27% of deaths from ischaemic heart disease. The combined effects of ambient (outdoor) and household air pollution cause about 6.5 million premature deaths every year. Today, an estimated 92% of the world¡¯s population lives in areas where air pollution exceeds WHO safety limits.

PM2.5 refers to atmospheric particulate matter (PM) that has a diameter of less than 2.5 micrometers, which is about 0.03 the diameter of a human hair. Fine particulars can come from various sources, such as power plants, motor vehicles, residential wood/leaves burning, forest fire, volcanic eruptions, agricultural burning, and dust storms. Particulars in this category are so small that they can only be detected with an electron microscope. Since they are so small and light, fine particles tend to stay longer in the air than heavier particles. This increases the chances of humans inhaling them into the bodies.

Particles smaller than 2.5 micrometers are able to bypass the nose and throat and penetrate deep into the lungs and some may even enter the circulatory system. Studies have found a close link between exposure to fine particles and premature death from heart and lung disease. Fine particles are also known to trigger or worsen chronic disease such as asthma, heart attack, bronchitis and other respiratory problems.

In 2013, PM was classified as a cause of lung cancer by WHO¡¯s International Agency for Research on Cancer (IARC). It is also the most widely used indicator to assess the health effects from exposure to ambient air pollution. On a very clear and non-hazy day, the PM2.5 concentration can be as low as 5 ¦Ìg/m3 or below. The 24-hour concentration of PM2.5 is considered unhealthy when it rises above 35 ¦Ìg/m3.

Ozone is aninorganic molecule with the chemical formula O3. The ozone layer at the higher atmosphere (in the stratosphere) is beneficial, preventing damaging ultraviolet light from reaching the Earth's surface.

However, low level ozone is an atmospheric pollutant. It is not emitted directly by car engines or by industrial operations, but formed by the reaction of sunlight on air containing hydrocarbons and nitrogen oxides that react to form ozone directly at the source of the pollution or many kilometers down wind.

It is well documented that ground-level ozone can harm lung function and irritate the respiratory system. Exposure to ozone (and the pollutants that produce it) is linked to premature death, asthma, bronchitis, heart attack, and other cardiopulmonary problems.

Long-term exposure to ozone has been shown to increase risk of death from respiratory illness. A study of 450,000 people living in United States cities saw a significant correlation between ozone levels and respiratory illness over the 18-year follow-up period. The study revealed that people living in cities with high ozone levels, such as Houston or Los Angeles, had an over 30% increased risk of dying from lung disease.

Nitrogen dioxide or NO2 is a nasty-smelling gas. NO2 primarily gets in the air from the burning of fuel. NO2 forms from emissions from cars, trucks and buses, power plants, and off-road equipment.

Nitrogen dioxide is a major air pollutant because it contributes to the formation of photochemical smog, which can have significant impacts on human health. NO2 inflames the lining of the lungs, and it can reduce immunity to lung infections. This can cause problems such as wheezing, coughing, colds, flu and bronchitis.

Increased levels of nitrogen dioxide can have significant impacts on people with asthma because it can cause more frequent and more intense attacks. Children with asthma and older people with heart disease are most at risk.

Sulfur dioxide or SO2 is a colorless gas. It is invisible and has a nasty, sharp smell. It reacts easily with other substances to form harmful compounds, such as sulfuric acid, sulfurous acid and sulfate particles.

About 99% of the sulfur dioxide in air comes from human activities. The main source of SO2 is the burning of coal and oil in power plants. It is also emitted by trains, large ships, motor vehicles, and other diesel equipment that burns high sulfur fuel, and by volcanic eruptions. Sulfur dioxide and nitrogen oxides can react with substances in the atmosphere to form acid rain.

Sulfur dioxide affects human health when it is breathed in. It irritates the nose, throat, and airways to cause coughing, wheezing, shortness of breath, or a tight feeling around the chest. The effects of sulfur dioxide are felt very quickly and most people would feel the worst symptoms in 10 or 15 minutes after breathing it in. Exposure to very high levels of sulfur dioxide can be life-threatening.

Children and the elderly, as well as people with asthma, heart or lung disease, are particularly sensitive to exposure to sulfur dioxide.

Carbon monoxide or CO is a colorless, odorless, tasteless and highly poisonous gas. High levels of carbon monoxide can be fatal but, unfortunately, it cannot be detected by human, as it has no taste or smell and cannot be seen.

CO is produced in the incomplete combustion of carbon-containing fuels, such as gasoline, natural gas, oil, coal, wood, and other fuels. The largest anthropogenic source of CO in most cities is vehicle emissions. It can also be released from tobacco smoke and natural sources such as volcanic eruptions and wildfires.

Breathing the high concentrations of CO will prevent the transport of oxygen (O2) in blood around the body. The result is that vital organs, such as the brain, nervous tissues and the heart, do not receive enough oxygen to work properly. This has health effects such as headache, nausea and vomiting, blurred vision, confusion, dizziness, chest pain, weakness, difficulty breathing, damage to the heart and brain and unconsciousness.

Carbon monoxide is most dangerous in enclosed spaces such as garages or indoor rooms.

People with heart problems are likely to suffer from more frequent and longer angina attacks, and they would be at greater risk of heart attack. Besides, children, unborn babies, pregnant women, and elderly are particularly at higher risk for exposure to carbon monoxide.

When the air quality is at unhealthy level, take the following steps to reduce exposure and protect you and your family's health:

•

E120 Air Quality Station is a compact air quality monitoring system designed for outdoor use. It measures major air pollutants (O3, NO2, SO2 and CO)*, fine particulate (PM2.5, PM10), ambient temperature, and humidity of the surroundings.
* Applicable for E120A model only

E120A is a complete set of air quality station that comes with air pollutants (O3, NO2, SO2 and CO), fine particulate (PM2.5, PM10), temperature, and humidity sensors.

E120B is a basic air quality station that comes with fine particulate (PM2.5, PM10), temperature, and humidity sensors. Air pollutant sensors are not included in E120B.

E120 series Air Quality Station is compact in design; it has built-in GPS and wireless connectivity for timely monitoring of air quality. Air quality data are sent to a secured cloud server in real-time where a deep learning-based method is used to extract spatiotemporal air quality features for predictive analysis. User can monitor the air quality of the designated area through mobile APP, anytime, anywhere.

Smart cities, gated residential areas, and schools. Air quality map can be generated for detecting sources of pollutants, as well as for forecasting of air quality in advance. By monitoring air quality and understanding its changing trend, we can make prompt actions to protect our family and children.

Selecting an appropriate site for the Air Quality station is critical for obtaining accurate data. Here are some general tips for installation:

Perform a Site Survey. Always perform a site survey to determine the suitable location for installation. Typically, the site should represent the general area of interest, and be away from obstructions such as buildings and trees.

Rooftop vs. Ground Mounting. If you are going to install the Air Quality station on a roof, be careful. Injuries, roof leakage and lightning strikes can occur for roof-mounted installations. We recommend a professional roofer to assist you in the installation.

In general, we recommend mounting the Air Quality station at least 4 feet above the roof line.

For ground installations, we recommend mounting the Air Quality station at least 5 feet above the ground. (Our station comes with an U-bot mounting structure that can be connected to a mast or pole).

The Air Quality station should be installed at a relatively open area, away from wind obstruction.
As a rule of thumb,

Distance to the nearest building = 4 ¦¶ (Obstruction Height ¨C Station Installed Height)
For example, if your building is 25 feet tall, and your Air Quality station is 5 feet above the ground, install the station at a distance of 80 feet, i.e.:

Distance = 4 ¦¶ (25' - 5') = 80'
If this clearance is not possible, you may need to install the station at a higher position, such as mounted on a post, or at a rooftop.

Lightning. Direct or indirect lightning strikes may damage the Air Quality station, even with lightning arrestors installed. In lightning prone areas, it is recommended to install a lightning rod and connect the mast to earth ground. Consult a licensed electrician for more information.

Birds and Rats. The Air Quality station requires an AC power supply (110/240 Vac). For wired installations, it is recommended you run the cables in electrical conduit. Rats and rodents may chew through the wires. Birds may excrement on your Air Quality station. You may want to install a decoy owl or spike strip around the station.

You can view the air quality data of your surroundings through our web portal and mobile APP. Valid users will be given an online account to login and view the historical, present, and forecast data.

Before shipment, all the sensors are calibrated and tested. Each sensor is very selective to a specific type of gas. Our long term testing has shown a failure rate of < 1.3 failures per million hours of operation (FPMH). In other words, the minimum mean-time between failures (MTBF) is > 790,000 hours (or > 90 unit-years!).

Under ideal conditions, all the sensors will exhibit a stable response for an indefinite period of time. For a typical environmental condition (23