Did you know about the Sprint Pro’s Ambient Air Monitor?

You probably know that the Sprint Pro has a host of useful functions, but have you ever scrolled through the menu of your Sprint Pro, found the ambient air monitor and wondered how you could use it?  

Well, you need wonder no longer – because in this post we will look at the Sprint Pro ambient air monitor and its uses.

Who needs to carry out ambient air monitoring? 

As a gas engineer, your need for ambient air monitoring may vary according to the type of work you do, but if you specialise in Carbon monoxide (CO)/Carbon dioxide (CO2) detection – for example, if you have CMDDA1 certification for dwellings or undertake COMCAT (commercial catering) reports in the UK, or have equivalent domestic or catering CO/CO2) certification elsewhere in the world – you will probably find this function very useful.  

How does ambient air monitoring work? 

In general terms, ambient air monitoring is simply the measurement of pollutants in the atmosphere, but in a gas detection context it refers to analysis of how much carbon monoxide is in the air.  

In some cases, the level of CO2 is also measured. The Sprint Pro 4 and Sprint Pro 6 both have a direct CO2 infrared sensor fitted, therefore they can measure both CO and CO2.

Ambient air monitoring may be carried out anywhere that CO and/or CO2 present a risk. For example, to detect CO leakages in the home (perhaps from a boiler), or to monitor CO2 levels in commercial catering premises.  

With the Sprint Pro, ambient air monitoring is carried out over a given time period, which may be anything from a few minutes to several days, during which time the analyser samples the ambient air at intervals of between one and thirty minutes. At the end of the test, the device gives readings for the current, peak and whole-test average rates for both CO and CO2. You can save these directly to your log and/or print them out as paper reports. 

Even when it comes to report printing, the Sprint Pro gives you options, so you can print as much or little of the relevant information as you need. This can be very handy when you have just taken literally hundreds of samples over a 7-day period! 

Ambient air monitoring for CO is available on all Sprint Pro models 

Why do I need ambient air monitoring functionality? 

Regardless of specialist certification, having the capacity to analyse ambient air is increasingly useful to HVAC professionals and gas engineers. This is particularly true in light of the COVID-19 pandemic, when the benefits of fresh air and good indoor ventilation have been highlighted. Excessive CO and CO2 are threats to both human and environmental health, and with growing awareness of this, and sustainability becoming an increasingly important social/political/policy topic, the need to quantify and measure them is likely to increase. 

Balloon gas safety: The dangers of Helium and Nitrogen 

Balloon gas is a mixture of helium and air. Balloon gas is safe when used correctly but you should never deliberately inhale the gas as it is an asphyxiant and can result in health complications. Like other asphyxiants, the helium in balloon gas occupies some of the volume normally taken by air, preventing that air being used to keep fires going or to keep bodies functioning.  

There are other asphyxiants used in industrial applications. For example, use of nitrogen has become almost indispensable in numerous industrial manufacturing and transport processes. While the uses of nitrogen are numerous, it must be handled in accordance with industrial safety regulations. Nitrogen should be treated as a potential safety hazard regardless of the scale of the industrial process in which it is being employed. Carbon dioxide is commonly used as an asphyxiant, especially in fire suppression systems and some fire extinguishers. Similarly, helium is non-flammable, non-toxic and doesn’t react with other elements in normal conditions. However, knowing how to properly handle helium is essential, as a misunderstanding could lead to errors in judgement which could result in a fatal situation as helium is used in many everyday situations. As for all gases, proper care and handling of helium containers is vital. 

What are the dangers? 

When you inhale helium knowingly or unknowingly it displaces air, which is partly oxygen. This means that as you inhale, oxygen that would normally be present in your lungs has been replaced with helium. As oxygen plays a role in many functions of your body, including thinking and moving, too much displacement poses a health risk. Typically, inhaling a small volume of helium will have a voice-altering effect, however, it may also cause a bit of dizziness and there is always the potential for other effects, including nausea, light headedness and/or a temporary loss of consciousness – all the effects of oxygen deficiency. 

  • As with most asphyxiants, nitrogen gas, like helium gas, is colourless and odourless. In the absence of nitrogen detecting devices, the risk of industrial workers being exposed to a dangerous nitrogen concentration is significantly higher. Also whilst helium often rises away from the working area due to its low density, nitrogen remains, spreading out from the leak and not dispersing quickly. Hence systems operating on nitrogen developing undetected leaks is a major safety regulatory concern. Occupational health preventive guidelines attempt to address this increased risk using additional equipment safety checks. The problem is low oxygen concentrations affecting personnel. Initially symptoms include mild shortness of breath and cough, dizziness and perhaps restlessness, followed by rapid breathing chest pain and confusion, with prolonged inhalation resulting in high blood pressure, bronchospasm and pulmonary edema. 
  • Helium can cause these exact same symptoms if it is contained in a volume and can’t escape. And in each case a complete replacement of the air with the asphyxiant gas causes rapid knockdown where a person just collapses where they stand resulting in a variety of injuries. 

Balloon Gas Safety Best Practice 

In accordance with OSHA guidelines, mandatory testing is required for confined industrial spaces with the responsibility being placed on all employers. Sampling atmospheric air within these spaces will help to determine its suitability for breathing. Tests to be carried out on the sampling air most importantly include oxygen concentrations, but also combustible gas presence and tests for toxic vapours to identify build ups of those gases. 

Regardless of the duration of stay, OSHA requires all employers to provide an attendant just outside a permit-required space whenever personnel are working within. This person is required to constantly monitor the gaseous conditions within the space and call for rescuers if the worker inside the confined space becomes unresponsive. It is vital to note that at no time should the attendant attempt to enter the hazardous space to conduct a rescue unassisted. 

In restricted areas forced draft air circulation will significantly reduce the build-up of helium, nitrogen or other asphyxiant gas and limit the chances of a fatal exposure. While this strategy can be used in areas with low nitrogen leak risks, workers are prohibited from entering pure nitrogen gas environments without using appropriate respiratory equipment. In these cases, personnel must use appropriate artificially supplied air equipment. 

Detecting dangers in dairy: What gases should you be aware of? 

Global demand for dairy continues to increase in large part due to population growth, rising incomes and urbanisation. Millions of farmers worldwide tend approximately 270 million dairy cows to produce milk. Throughout the dairy farm industry there are a variety of gas hazards that pose a risk to those working in the dairy industry.  

What are the dangers workers face in the dairy industry?

Chemicals

Throughout the dairy farm industry, chemicals are used for variety of tasks including cleaning, applying various treatments such as vaccinations or medications, antibiotics, sterilising and spraying. If these chemicals and hazardous substances are not used or stored correctly, this can result in serious harm to the worker or the surrounding environment. Not only can these chemicals cause illness, but there is also a risk of death if a person is exposed. Some chemicals can be flammable and explosive whilst others are corrosive and poisonous. 

There are several ways to manage these chemical hazards, although the main concern should be in implementing a process and procedure. This procedure should ensure all staff are trained in the safe use of chemicals with records being maintained. As part of the chemical procedure, this should include a chemical manifest for tracking purposes. This type of inventory management allows for all personal to have access to Safety Data Sheets (SDS) as well as usage and location records. Alongside this manifest, there should be consideration for the review of current operation.  

  • What is the current procedure?  
  • What PPE is required?  
  • What is the process for discarding out of date chemicals and is there is a substitute chemical that could pose less of a risk to your workers? 

Confined Spaces

There are numerous circumstances that could require a worker to enter a confined space, including feed silos, milk vats, water tanks and pits in the dairy industry. The safest way to eliminate a confined space hazard, as mentioned by many industry bodies, is to employ a safe design. This will include the removal of any need to enter a confined space. Although, this may not be realistic and from time to time, cleaning routines need to take place, or a blockage may occur, however, there is a requirement to ensure there is the correct procedures to address the hazard. 

Chemical agents when used in a confined space can increase the risk of suffocation with gases pushing out oxygen. One way you can eliminate this risk is by cleaning the vat from the outside using a high-pressure hose. If a worker does need to enter the confined space, check that the correct signage is in place since entry and exit points will be restricted. You should consider isolation switches and check that your staff understand the correct emergency rescue procedure if something were to happen. 

Gas Hazards

Ammonia (NH3) is found in animal waste and slurry spreading on farming and agricultural land. It is characteristically a colourless gas with a pungent smell that arises through the decomposition of nitrogen compounds in animal waste. Not only is it harmful to human health but also harmful to livestock wellbeing, due to its ability to cause respiratory diseases in livestock, and eye irritation, blindness, lung damage, alongside nose and throat damage and even death in humans. Ventilation is a key requirement in preventing health issues, as poor ventilation heightens the damage caused by this gas.  

Carbon dioxide (CO2) is naturally produced in the atmosphere; although, levels are increased through farming and agricultural processes. CO2, is colourless, odourless, and is emitted from agricultural equipment, crop and livestock production and other farming processes. CO2 can congregate areas, such as waste tanks and silos. This results in oxygen in the air to be displaced and increasing the risk of suffocation for animals and humans.  Sealed silos, waste and grain storage spaces are specifically dangerous as CO2 can accumulate here and lead to them being unsuitable for humans without an external air supply. 

Nitrogen dioxide (NO2) is one of a group of highly reactive gases known as oxides of nitrogen or nitrogen oxides (NOx). At worst, it can cause sudden death when consumed even from short term exposure. This gas can cause suffocation and is emitted from silos following specific chemical reactions of plant material. It is recognisable by its bleach-like smell and its properties tend to create a red-brown haze. As it gathers above certain surfaces it can run into areas with livestock through silo chutes, and therefore poses a real danger to humans and animals in the surrounding area. It can also affect lung function, cause internal bleeding, and ongoing respiratory problems. 

When should gas detectors be used?

Gas detectors provide added value anywhere on dairy farms and around slurry silos, but above all: 

  • When and where slurry is being mixed 
  • During pumping and bringing out slurry
  • On and around the tractor during slurry mixing or spreading 
  • In the stable during maintenance work on slurry pumps, slurry scrapers and the like 
  • Near and around small openings and cracks in the floor, e.g., around milking robots 
  • Low to the ground in poorly ventilated corners and spaces (H2S is heavier than air and sinks to the floor) 
  • In slurry silos 
  • In slurry tanks 

Products that can help to protect yourself 

Gas detection can be provided in both fixed and portable forms. Installation of a fixed gas detector can benefit a larger space to provide continuous area and staff protection 24 hours a day. However, a portable detector can be more suited for worker’s safety. 

To find out more on the dangers in agriculture and farming, visit our industry page for more information. 

Carbon Dioxide: What are the dangers in the Food and Beverage Industry? 

Almost all industries must monitor gas hazards, with the food and beverage industry no exception. Although, there is a lack of awareness regarding the dangers of carbon dioxide (CO2) and the dangers those working in the industry face. CO2 is the most common gas in the food and beverage industry because it is used in the carbonation of drinks, to propel beverages to the tap in pubs and restaurants and to keep food items cold during transportation in the form of dry ice. It is also naturally produced in beverage manufacturing processes by leavening agents like yeast and sugar. Although CO2 may seem harmless at first glance as we exhale it with every breath, and plants need it for survival, the presence of carbon dioxide becomes a problem when its concentration rises to dangerous levels.

The Dangers of CO2

Carbon dioxide occurs naturally in the atmosphere (typically 0.04% in air). CO2 is colourless and odourless, heavier than air, and tends to sink to the floor. CO2 collects in cellars and at the bottom of containers and confined spaces such as tanks or silos.

Since CO2 is heavier than air, it quickly displaces oxygen at high concentrations can result in asphyxiation due to a lack of oxygen or breathable air. Exposure to CO2 is easy, especially in a confined space like a tank or a cellar. Early symptoms of exposure to high levels of carbon dioxide include dizziness, headaches, and confusion, followed by loss of consciousness. Accidents and fatalities occur in the food and beverage industry due to a carbon dioxide leak. Without proper detection methods and processes in place, everyone at a facility could be at risk.

Gas Monitors – what are the benefits?

Any application that uses carbon dioxide puts workers at risk, and the only way to identify high levels before it’s too late is to use gas monitors.

Gas detection can be provided in both fixed and portable forms. Installation of a fixed gas detector can benefit a larger space such as plant rooms to provide continuous area and staff protection 24 hours a day. However, a portable detector can be more suited for worker safety in and around the cylinder storage area and in spaces designated as a confined space. This is especially true for pubs and beverage dispensing outlets for the safety of workers and those unfamiliar with the environment, such as delivery drivers, sales teams or equipment technicians. The portable unit can easily be clipped to clothing and will detect pockets of CO2 using alarms and visual signals, indicating that the user should immediately vacate the area.

Personal gas detectors continuously monitor the air in workers’ breathing zone when worn correctly,  to give them better awareness and the information they need to make smart decisions in the face of danger. Not only can gas monitors detect carbon dioxide in the air, but they can also alert others if an employee is in danger. Carbon dioxide can be monitored using a single gas monitor or by using a multi-gas monitor with a dedicated carbon dioxide sensor. It is important to note the carbon dioxide can escalate to dangerous levels before an oxygen sensor would alarm.

Where do Flue Gas Analysers Fit into the UK Government’s Decarbonisation Plans?

When the UK government announced, in March 2021, that £1 billion of already-allocated funds would be redirected to projects designed to reduce greenhouse gases, the energy sector sat up and listened. And with good reason – as it turned out, £171 million will be allocated to an industrial decarbonisation plan that focuses on hydrogen gas generation and carbon capture and storage technologies.  

However, the news extended beyond green energy production and is relevant to domestic and industrial HVAC applications. In a gesture that reflects the role HVAC engineers and manufacturers can play in sustainability, more than £900 million will be spent upgrading public buildings, like schools and hospitals, with greener fittings such as heat pumps, solar panels and insulation, which will reduce carbon dioxide (CO2) emissions.

But where does this leave the individual households and business units that many HVAC staff visit daily? That is a question that several commentators have asked, and it seems that – for now at least – the main drive to reduce the environmental impact of privately-owned heating and plumbing systems will continue to come from the manufacturers, engineers and installers working in the HVAC sector. 

And that’s quite a responsibility. According to the Office for National Statistics, in 2020, there were approximately 27.8 million households in the UK; government statistics from 2019 indicate that around 15% of greenhouse gas emissions in the UK (specifically of carbon dioxide, along with methane, F gases and nitrous oxide) came from those residential settings. That’s a lot of excess CO2 to clean up. 

So, what can HVAC people do to help decarbonisation? 

If they have decent equipment, heating engineers and plumbers can help to reduce that figure by 15%. For example, they are well placed to measure CO2 and other greenhouse gases: while most flue gas analysers will measure CO2, some can also measure NO/NOx (for example, the Sprint Pro 5 and Sprint Pro 6) well.  

A flue gas analyser that gives a wide range of easy-to-read and interprets measurements allows engineers to see when appliances are not working correctly and whether an upgrade (for example, to a government-subsidised heat pump) might be in order. 

This is a pressing need: many households hang onto appliances for as long as possible, even though older appliances tend to be much less environmentally friendly than their modern counterparts. This is bad enough for the environment, but using a malfunctioning older appliance is the worst of all possible outcomes. 

A good flue gas analyser will provide the readings required to convince many customers to decarbonise their homes or businesses more effectively. It will also allow the engineer to fix many problems in more modern and efficient appliances, bringing them back to their original operating standards and protecting the planet once more. 

Helping to reach net zero 

In late 2021, the UK government set out its plan to reach net-zero emissions by 2050 and every heating engineer in the country has a part to play in that project. While checking flue gases may be an everyday event for many HVAC engineers, the fact remains that household and business emissions account for a substantial proportion of CO2 output and emissions of other dangerous gases. While persuading a single household to operate with lower carbon emissions may not seem like a big deal, the impact can be very substantial when this is scaled up across the country. 

What is Biogas?

Biogas most commonly known as biomethane is a renewable fuel constructed through the breakdown of organic matter (such as animal manure, municipal rubbish/ waste, plant material, food waste or sewage) by bacteria in an oxygen-free environment through a process called anaerobic digestion. Biogas systems use anaerobic digestion to repurpose these organic materials, converting them into biogas, of which consists of both energy (gas), and valuable soil products (liquids and solids). It can be used for many different functions; these include vehicle fuel and for heating and electricity generation.  

What industries is Biogas used in?

Biogas can be produced through the combustion process to produce heat only. When burned, one cubic metre of biogas produces around 2.0/2.5 kWh of thermal energy, providing the nearby buildings with the heat generated. The unused heat is dismissed, and unless it is heated and converted into hot water through a local pipe network into local houses, it is wasted. This concept of heating water and transferring to homes as part of central heating is popular in some Scandinavian countries. 

Biogas is eligible for support under the Renewable Transport Fuel Obligation due to the combustion of biomethane from vehicles being more environmentally friendly than those who use transport fuels such as modern petrol and diesel, thereby helping reduce greenhouse emissions. Examples of renewable transport fuels in vehicles that are formed out of biogas are compressed natural gas (CNG) or liquefied natural gas (LNG).  

Electricity can be generated from the combustion of biogas. Electricity is easier to transport and measure than heat and gas supply, however, requires the right infrastructure in order for it to feed into the grid, that is expensive and complex. Although, generating green electricity can benefit the generators (households and communities) by using the Feed-in Tariffs (FiTs) or for bigger players can maximise the Renewable Obligation Certificates (ROCs) for industrial scale production, thereby leading to a reduction in cost as well as being better for the environment. 

Other industries include hospitality, manufacturing, retail and wholesale. 

Which gases does Biogas contain? 

Biogas consists mainly of methane and carbon dioxide. The most common ratio is 60% CH4 (methane) and 40% CO2 (carbon dioxide), However, the respective quantities of these will vary depending on the type of waste involved in the production of the resulting biogas, therefore the most common ratio will be 45 to 75% methane and carbon dioxide from 55 to 25%. Biogas also contains small amounts of hydrogen sulphide, siloxanes and some moisture.  

What are the key benefits?

There are several reasons why biogas technology is useful as an alternate form of technology: Primarily, the raw material used is very cheap, and to farmers it is practically free with the biogas having the ability to be used for a range of household and farming applications. The burning of biogas does not produce harmful gases; therefore, it is environmentally clean. One of the most convenient benefits of biogas is that the technology required for its production is relatively simple and can be reproduced in large or small scale without the need for a large initial capital investment. As this type of energy is a renewable, clean source of energy that relies on a carbon-neutral process, therefore no new amounts of carbon are released into the atmosphere when using biogas. As well as it helping to divert food waste from landfills, positively impacting the environment and economics. Biogas also helps to reduce soil and water contamination from animal and human waste, allowing for the maintenance of a healthy and safe environment for many communities worldwide. With methane being a contributor to climate change, biogas contributes to its reduction that is emitted into the atmosphere, helping to counteract its impact on climate change, thereby helping to possibly help with its immediate impact on the environment.  

However, biogas as a source of energy does have its disadvantages, one is that Biogas production is dependent on a biological process that doesn’t have the ability to be controlled fully. Additionally, biogas works better in warmer climates, this consequently means biogas doesn’t have the capacity to be accessible equally worldwide. 

Is Biogas Good or Bad?

Biogas is an outstanding source of clean energy, due to it possessing a lower impact on the environment than fossil fuels. Although biogas doesn’t have a zero impact on the ecosystems, it is carbon neutral. This is because biogas is produced from plant matter, of which has previously fixed carbon from carbon dioxide in the atmosphere. A balance between the carbon being let out as a result of producing biogas and the amount absorbed from the atmosphere is maintained. 

Have you ever thought about the dangers behind your favourite beverage?

Beer Production

It’s only natural for us to associate the need for gas detection in the oil and gas, and steel industries, but have you thought about the need to detect hazardous gases such as carbon dioxide and nitrogen in the brewing and beverage industry?

Maybe it’s because nitrogen (N2) and carbon dioxide (CO2) are naturally present in the atmosphere. It could be that CO2 is still under-valued as a hazardous gas. Although in the atmosphere CO2 remains at very low concentrations – around 400 parts per million (ppm), greater care is needed in brewery and cellar environments where in confined spaces, the risk of gas canisters or associated equipment leaking could lead to elevated levels. As little as 0.5% volume (5000ppm) of CO2 is a toxic health hazard. Nitrogen on the other hand, can displace oxygen.

CO2 is colourless, odourless and has a density which is heavier than air, meaning pockets of CO2 gather low on the ground gradually increasing in size. CO2 is generated in huge amounts during fermentation and can pose a risk in confined spaces such as vats, cellars or cylinder storage areas, this can be fatal to workers in the surrounding environment, therefore Health & Safety managers must ensure the correct equipment and detectors are in place.

Brewers often use nitrogen in multiple phases of the brewing and dispensing process to put bubbles into beer, particularly stouts, pale ales and porters, it also ensures the beer doesn’t oxidise or pollute the next batch with harsh flavours. Nitrogen helps push the liquid from one tank to another, as well as offer the potential to be injected into kegs or barrels, pressurising them ready for storage and shipment. This gas is not toxic, but does displace oxygen in the atmosphere, which can be a danger if there is a gas leak which is why accurate gas detection is critical.

Gas detection can be provided in the form of both fixed and portable. Installation of a fixed gas detector can benefit a larger space such as plant rooms to provide continuous area and staff protection 24 hours a day. However, for worker safety in and around cylinder storage area and in spaces designated as a confined space, a portable detector can be more suited. This is especially true for pubs and beverage dispensing outlets for the safety of workers and those who are unfamiliar in the environment such as delivery drivers, sales teams or equipment technicians. The portable unit can easily be clipped to belts or clothing and will detect pockets of CO2 using alarms and visual signals, indicating that the user should immediately vacate the area.

At Crowcon, we’re dedicated in growing a safer, cleaner, healthier future for everyone, every day by providing best in class gas safety solutions. It’s vital that once gas detectors are deployed, employees should not get complacent, and should be making the necessary checks an essential part of each working day as early detection can be the difference between life and death.

Quick facts and tips about gas detection in breweries:

  • Nitrogen and CO2 are both colourless and odourless. CO2 being 5 times heavier than air, making it a silent and deadly gas.
  • Anyone entering a tank or other confined space must be equipped with a suitable gas detector.
  • Early detection can be the difference between life and death.

What you need to be aware of when…

…zeroing your CO2 detector

Without wishing to sound accusing, where were you the last time you zeroed your CO2 detector?  In your vehicle?  In the office before you travelled to the location you were working in?

It might not have caused you problems so far, but the air around you can make a big difference to the performance of your CO2 detector.

What is zeroing?

Zeroing your detector means calibrating it so its ‘clean air’ gas level indication is correct.

When is zero not really zero?

Many CO2 detectors are programmed to zero at 0.04% CO2 rather than 0%, because 0.04% is the normal volume of CO2 in fresh air.  In this case, when you zero your detector, it automatically sets the baseline level to 0.04%.

What happens if you zero your CO2 monitor where you shouldn’t?

If you zero your detector where you shouldn’t, the actual CO2 concentration could be much higher than the standard 0.04% – up to ten times higher, in some cases.

The end result?  An inaccurate reading, and no true way of knowing how much CO2 you’re actually exposed to.

What are the dangers of CO2?

CO2 is already in the earth’s atmosphere, but it doesn’t take much for it to reach dangerous levels.

  • 1% toxicity can cause drowsiness with prolonged exposure
  • 2% toxicity is mildly narcotic and causes increased blood pleasure, pulse rate, and reduced hearing
  • 5% toxicity causes dizziness, confusion, difficulty in breathing, and panic attacks
  • 8% toxicity causes headaches, sweating and tremors. You’ll lose consciousness after five to ten minutes of exposure.

What can I do to make sure I’m safe?

Only zero your instruments if you really have to, and make sure you zero your detector in fresh air – away from buildings and CO2 emissions, and at arm’s length to make sure your own breath doesn’t affect the reading.

What if I think my zero reading is incorrect?

It’s best to test the instrument with 100% nitrogen to check the real zero point, and then with a known level of CO2 test gas. If the zero gas reading is incorrect, or any other gas reading for that matter, the detector will need a full service calibration – contact your local service provider for help.

If you have a Crowcon detector, you can use our Portables Pro software to correct its zero reading.  For further information, call Crowcon customer support on +44 (0)1235 557711.

The don’ts and don’ts of zeroing your CO2 detector

Unlike other toxic gases, carbon dioxide (CO2) is all around us, albeit at levels too low to cause health issues under normal circumstances. It raises the question, how do you zero a CO2 gas detector in an atmosphere where CO2 is present?

Continue reading “The don’ts and don’ts of zeroing your CO2 detector”

Carbon Dioxide – Friend and Foe?

Carbon dioxide (CO2) gas is commonly used in the manufacture of popular beverages. The leak at the Greene King brewery in Bury St Edmunds (UK) last week, is a reminder of the importance of effective gas detection. It resulted in twenty workers having to be rescued by emergency services and local residents being evacuated. So what is carbon dioxide, why is it dangerous and why do we have to monitor it carefully?

Continue reading “Carbon Dioxide – Friend and Foe?”