News

Guest post by Michael Forster, Edaphic Scientific Pty Ltd

Everyone knows that plants need carbon dioxide to grow. But fewer people know that carbon dioxide can also effect plant transpiration and even the water balance of entire ecosystems and catchments. Even fewer people know that carbon dioxide can affect biodiversity and which plant species are more common than other species.

Let’s just leave aside all of the topics on how increasing carbon dioxide is leading to global warming and how this, in turn, is impacting on plant species. Let’s just focus purely on how increasing atmospheric carbon dioxide changes the fundamental physiology of plants and how this, in turn, can lead to changes in transpiration and which species are more common in a forest.

Firstly, how do we know all of this? Scientists have been conducting experiments for years now where they have artificially increased atmospheric carbon dioxide around plants and forests.

They do this via experiments called FACE – or Free Air Carbon Enrichment – where massive towers gorge out copious amounts of CO2. Image: FACE experiment at Duke University, North Carolina, USA (source: https://www.czen.org/content/duke-forest-face-experiment)

Another approach is to grow a large tree in what is called a Whole Tree Chamber and manipulate carbon dioxide levels in the chamber. Image: Whole Tree Chamber Experiment at University of Western Sydney, Australia (source: http://www.uws.edu.au/hie/facilities/whole_tree_chambers)

What these experiments have generally shown is that plants actually like it when there is more carbon dioxide in the atmosphere. Plants generally grow larger and faster with more CO2. The process is similar to when you add fertilizer to the soil to assist the plant’s growth. Instead, we are adding fertilizer to the atmosphere in the form of more carbon dioxide. As there is more carbon dioxide in the atmosphere, it is generally easier for plants to perform photosynthesis and accumulate biomass.

In terms of transpiration, or plant water use, an increase in atmospheric CO2 means that stomata, or the pores on leaves that exchange gases between the leaf and the atmosphere, do not need to open as much. This means that, at the scale of a leaf, less water is lost and there is lower transpiration. With increased photosynthesis and lower water loss, then the water efficiency of plants is increased.

So it seems that more carbon dioxide in the atmosphere is a good thing for plants – they grow faster and use less water. However, nothing in biology is so simple. Yes the water loss at the scale of a leaf is lower, however, there are more leaves on the plant because it is growing faster and bigger. So, at the scale of the entire plant, water use or transpiration is actually higher.

This may seem trivial but consider this: a 30 metre (100 foot) tall tree transpires about 200 litres (53 gallons) on a good day. A forest of woodland contains many thousands to millions of individual trees all transpiring about 200 litres per day. This can impact on water reserves – particularly around dams for drinking water or irrigation. With increased atmospheric carbon dioxide, all of those trees may potentially transpire more water and having a greater impact on water supplies.

Also, not all species of plants are created equally. Increasing carbon dioxide does improve growth but some species perform better than others. In a woodland or rainforest, some species may grow better and out compete their neighboring plants. That is, some species may become more common and others scarce. This may then impact on the animals that rely on those plants for food and shelter.
Increasing atmospheric carbon dioxide can benefit plants – something greenhouse and glasshouse growers use to their advantage. However, the process and outcomes are complex. In the real world increasing carbon dioxide does not benefit all plants.

Graduate student uses our K-33 CO2 sensor to study the NOx-PM tradeoff in modern deisel engine design.

Recently we had a client purchase a pSense portable CO2 meter to measure CO2 levels in his poultry production facility in Italy. 

 If you or your children are an indoor ice skater or hockey player, you should be aware of the potential danger of indoor ice arenas resurfaced with gas-powered ice resurfacing machines like Zambonis.

Exhaust Fumes in a Enclosed Areas

Carbon monoxide fumes and micro-particles from Zamboni engine exhaust linger inside enclosed ice rinks, and can hurt those who inhale them. Unlike carbon dioxide (CO2), carbon monoxide (CO) is potentially harmful at even small levels. OSHA limits carbon monoxide exposure to 25ppm both for short-term exposure limit (STEL) and time-weighted average (TWA) over an 8-hour workday.

With an ice resurfacing machine only running for a few minutes a day, it would seem like this is a small problem. Yet regular news articles appear across the country describing people in enclosed ice rinks being sent to the hospital with CO poisoning.

• As far back as 2002, the EPA issued an extensive report detailing the need for ice rink owners and managers to be acutely aware of the dangers of "Indoor Air Problems for Ice Arenas," such as what causes the problems, how CO and NO2 gases and particulate matter (PM) affects your health, and the "Action Steps of Ice Arena Owners and Managers."
• In 2009, ESPN ran a story titled "Study finds health hazards at rinks." The article stated that "In the past six months, nearly 200 people have been sickened by carbon monoxide, nitrogen dioxide or ultra-fine particles emitted from poorly maintained ice resurfaces at indoor ice arenas."
• In 2011, 61 people in Gunnison, Colorado were sent to the hospital with CO poisoning.

Long-term exposure can be harmful too. Former Ice Capades dancer Linda Davis was diagnosed with long-term carbon monoxide exposure in her 40s, after decades of ice time. She has lung damage, chronic memory problems, and must use a respirator.

One solution is for ice-rink owners to replace old gas-powered ice-resurfacing machines with newer electric ones. However, this can be a significant capital expense. A better solution would be for ice rink owners to voluntarily test the CO and NO2 levels with their current equipment, and take corrective action if necessary. For example, CO2Meter.com’s Carbon Monoxide CO Handheld Detector can quickly warn ice-rink owners, skaters, or ice-rink employees if CO reaches dangerous levels.

Ice-rinks could also choose a more permanent solution, the Carbon Monoxide (CO) Fixed Gas Detector w/ Remote Sensor (0-50ppm) is a wall mounted gas detection solution that has 3 configurable relays, connects to most BMS systems, and has audible and visual indicators to alert of an unsafe breathing environment. 

 

Conclusion

Few states in the US have laws requiring carbon monoxide detectors in ice rinks, and OSHA air quality standards are “suggestions”, not requirements. For people who spend much of their time in an indoor ice arena, knowing the CO levels in the air around them is important for their health and safety. For questions on the right option for you, contact the experts at CO2Meter online or call 877.678.4259.