The environmental standards applied to the quality of water and air that we each come into contact with on a daily basis are vital in terms of our health and well-being. The water we drink and the quality of the air that we breathe are of the utmost importance, and it’s easy, when living in a developed, industrialised nation, to take high standards for granted. Throughout the world, however, people face a daily struggle to source clean drinking water or to survive in an atmosphere which has become clogged with unhealthy pollutants. It’s vital, therefore, to constantly upgrade and develop the monitoring systems which we use, and to ensure that we don’t rest on our laurels and feel that the job has been done. As the occasional high profile contamination case demonstrates, constant vigilance is needed if the highest standards are to be maintained.
When it comes to ensuring the purity of the water supply to the home, it’s important not to merely assume that water is a natural product which merely needs to be collected and then delivered via a series of reservoirs and pipes. On the contrary, in order to make sure that the water which people drink is of the highest possible quality it has to be filtered and cleaned when first collected and then requires the addition of various disinfectants and chemicals in order to ensure that no harmful bacteria are present.
Just a quick run through some of the chemicals which can be present in drinking water will underline exactly how far from being a totally pure natural product it in fact is. The drinking water delivered to most homes in the UK is likely to contain at least trace elements of the following:
- Fluorine compounds
- Trihalomethanes (THMs)
- Salts of:
Some of these, such as chlorine and chloriamines are added by water companies in order to kill bacteria. Fluorine and orthophosphate are added for prevention of health risk. Other substances make their way into the system during the process of delivery. Pesticides, for example, can be present in water which runs off from farm land and into sources such as rivers and reservoirs. Whilst these elements are normally present in such small amounts that there is little chance of them doing any harm, the fact that they are there at all merely underlines the necessity to remain in a state of constant vigilance.
When it comes to monitoring the presence of gas, on the other hand, the matter is one of a more urgent nature. Many gases are toxic, highly flammable or both, meaning that if they’re allowed to build up to any significant degree they may cause ill health or even death or, at worse trigger dangerous explosions.
The devices used to detect the presence of gas range in sensitivity and type, from large scale industrial units to small, battery operated alarms to be placed in a domestic setting. The actual mechanism used may vary dependent upon the type of gas which is being looked for, and the amount which will have to be present to trigger an emergency situation.
The most common types of gas monitoring and detection techniques are the Infrared Point Sensor, Ultrasonic gas detectors, electrochemical gas detectors, and Semiconductor Sensors. Below is a brief summary of each and the type of situation they may be used in:
Electrochemical Detectors – A sensor within this device will measure the concentration of gas in the atmosphere and an alarm will be triggered if the amount rises above a safe threshold. As a generalised monitoring device which tends to remain fairly stable once put in place, a detector of this kind will be used in a wide variety of circumstances, such as a chemical plant, a gas storage facility or a refinery.
Infrared Point Detectors – This type of detector measures the wave length of a beam of infra-red light passing through the area being checked, and compares this to a beam outside the area. Measuring the difference between the two is a way of calculating the concentration of gas which is present, thus ensuring it isn’t too high. Monitoring of this kind is used in areas such as chemical plants, water treatment facilities and other areas where gas has been known to build up to explosive levels.
Semiconductor Detectors – This type of detector works by measuring a chemical reaction brought about by the presence of certain gases. Commonly, semiconductor detectors are used in the home to detect the presence of carbon monoxide which, if allowed to escape and build up can prove fatal.
Ultrasonic Detectors – Ultrasonic detectors use sound waves to measure the rate at which gas is escaping from a leak. The main advantage of this type of monitor is that it can detect gas leaks without the gas itself having to reach the concentrated levels required by other sensors. For that reason, it is often used when outdoors, in places such as oil rigs, metering stations and any other plant which might require large amounts of exterior piping.
Photo Credits: Paul Garland