Air quality is the condition of the air we breathe, in terms of pollution. It is an environmental concern because air pollution can be detrimental to human health. Air pollution may cause lung cancer, respiratory diseases and other serious health problems. It may also aggravate existing heart conditions.
Air pollution can be caused by both natural and human activities. Natural causes include volcanic eruptions and dust storms. Human activities, such as the burning of fossil fuels in vehicles, power plants and factories, can cause air pollution through the release of pollutants into the air.
The main pollutants affecting air quality are:
Sulphur dioxide (SO2) – produced by burning fossil fuels (coal and oil) or wood. SO2 reacts with water vapour in the atmosphere to form sulphuric acid, which is deposited as acid rain.
Nitrogen oxides (NOx) – produced by combustion processes such as vehicle engines, heating systems and power plants. NOx reacts with sunlight to form ozone, which damages plants and also irritates the lungs of humans and animals.
Particulate matter (PM) – emitted from power plants, vehicle exhausts and industrial processes. PM can have various chemical compositions but is usually composed of a mixture of very small solid particles (including soot), liquid droplets or a mixture of both solid particles and liquid droplets. It is sometimes referred to as 'smog'. PM may contain many different chemicals including acids (such as nitrates), organic compounds (such as benzene), metals or mineral dusts/aerosols.
PM 2.5 (particles smaller than 2.5 micrometres) and below are harmful to health when breathed in because they are small enough to enter deep into the lungs and bloodstream.
Some types of PM are not directly emitted but instead form from gases emitted from fuel combustion or other sources through a series of chemical reactions in the atmosphere (reactive gas-phase formation).
Carbon monoxide (CO) – emitted from vehicle exhausts, and industrial processes. It is colourless and odourless. CO can cause headaches, nausea, dizziness and confusion.
Hydrocarbons (HC) – emitted from vehicle exhausts, industry and open burning of waste. HC is a component of air pollution that can cause cancer in humans.
Volatile organic compounds (VOC) – emitted from vehicle exhausts, industry and paint strippers. VOCs are the largest group of air pollutants in Europe today. They contribute to the formation of ground-level ozone and smog, which are linked to a variety of health problems including respiratory diseases such as asthma and bronchitis, heart disease and cancer.
Polycyclic aromatic hydrocarbons (PAH) – emitted from combustion processes such as vehicle engines or open burning of waste materials containing coal or oil. PAH can be formed during incomplete combustion from many different types of organic matter including oil/petroleum products, coal or natural gas, tobacco smoke or pyrolysis gasoline vapours at temperatures above 300 degrees Celsius (572 degrees Fahrenheit).
Why it is important to measure air quality:
In the UK, many people are exposed to levels of air pollution that exceed the legal limits. The most important of these pollutants is particulate matter (PM). PM can be particularly harmful to health because it is small enough to enter deep into the lungs and contains chemicals that can be harmful when breathed in. As a result, monitoring of air quality is an important aspect of public health.
How to measure air quality:
Measuring air quality in your home is now easier than ever with affordable and accurate air quality monitors such as BREATHE|Smart 2. It uses a direct sampling method to alert you to high levels of PM pollution so you know when you need to ventilate, and can show you when concentrations are back to a safe level. It informs you of the Air Quality Index in your home as well as the PM 2.5 count. Being able to see at a glance the particulate matter concentrations and Air Quality Index a glance helps protect the health of you and your family.