ventilation

Controlled Environment Agriculture | Earth Wise

October 24, 2023 By EarthWise Leave a Comment

The term “controlled environment agriculture” (or CEA) refers to any number of systems embodying a technology-based approach to farming. CEA can range from simple shade structures to greenhouses to full indoor or vertical farms. At the most advanced level, CEA systems are fully automated, closed loop systems with controlled lighting, water, and ventilation. Many systems make use of hydroponics rather than traditional soil.

The goal of CEA systems is to provide optimum growing conditions for crops and prevent disease and pest damage.

A recent study by the University of Surrey in the UK sought to understand the impact of using CEA systems to grow lettuce, which is a high-value crop that is often grown in such systems.

The study found that, on average, CEA methods produce double the crop yields compared to field-based agriculture. They also found that the cultivation time of CEA yields was, on average, 40 days. This compares with an average cultivation time of 60-120 days for field-based agriculture. More specifically, production of lettuce using CEA was 50% faster in the summer and up to 300% faster in the winter.

Climate change presents many difficult challenges to society, not the least of which is its threat to food security. Controlled environment agriculture could allow cultivation of crops in harsh environments and in the face of changing climates. Quantifying the benefits CEA can have on yield and growth provides important information for advancing our understanding of where and when this technology can bring the most value to society.

**********

Web Links

Using artificial methods for growing crops could help solve global food security

Photo, posted February 24, 2013, courtesy of Cindy Kurman / Kurman Photography via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Living in a Carbon Bubble | Earth Wise

July 18, 2022 By EarthWise Leave a Comment

The earth’s atmosphere is a little over 0.04% carbon dioxide, currently about 420 parts per million. That’s more than it’s been in millions of years and is changing our climate. But these levels of CO2 are not enough to directly affect people.

However, people are sensitive to the amount of carbon dioxide they are breathing. It is actually an indoor pollutant. High concentrations have been shown to reduce our cognitive performance, our health, and our comfort. For example, a study in 2012 showed that performance in a variety of cognitive function tests was reduced by 12% when CO2 levels reached 1,000 parts per million and by 51% at 2,500 ppm.

How common are high levels of carbon dioxide? Pretty common. Offices often have CO2 levels of 600 ppm or higher, but 5% of US offices have average concentration about 1000 ppm and some conference rooms can reach 1900 ppm. Classrooms often reach average levels above 1000 ppm. Passenger aircraft have average levels around 1400 ppm during flight, and can peak over 4,000 ppm. Cars with one occupant with the windows closed and the air recirculating have levels above 4,000 ppm.

Where does it all come from? From us. We exhale CO2 and if we are in enclosed spaces with insufficient air circulation and ventilation, we end up living in a carbon dioxide bubble. Most of us live with high CO2 levels – all day and every day. It is a form of indoor pollution that has not gotten enough attention.

**********

Web Links

I’m living in a carbon bubble. Literally.

Photo, posted October 24, 2013, courtesy of Cory W. Watts via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Houseplants And Indoor Air Quality | Earth Wise

April 11, 2022 By EarthWise Leave a Comment

Many of us have houseplants in our homes and offices. The foliage and flowers add beauty and comfort to our indoor spaces. But it turns out that there are health advantages as well.

Many studies have demonstrated that indoor houseplants can help keep you happier and healthier by improving your mood, reducing fatigue, lowering stress and anxiety, and improving focus. Houseplants can also improve indoor air quality.

According to a new study by researchers from the University of Birmingham in the U.K. in partnership with the Royal Horticultural Society, ordinary houseplants can potentially make a significant contribution to reducing indoor air pollution.

The researchers tested three types of houseplants commonly found in homes in the U.K: Peace lily, corn plant, and fern arum. These plants are easy to maintain and not overly expensive.

In the study, the research team exposed these houseplants to nitrogen dioxide, which is a common indoor pollutant. The plants were isolated in a test chamber containing levels of nitrogen dioxide comparable to what might be in an office situated next to a busy road. The researchers found that all the plants were able to remove about half of the nitrogen dioxide in the chamber in just one hour.

In a poorly ventilated small office with high levels of air pollution, the researchers calculated that five houseplants would remove up to 20% of the nitrogen dioxide. In a larger space, the effect would be smaller – around 3.5% – although this figure could be increased by adding more plants.

Bringing nature indoors is one way to breathe cleaner air.

**********

Web Links

Common houseplants can improve air quality indoors

Reducing air pollution with plants

Photo, posted September 21, 2014, courtesy of Olin Gilbert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Indoor Pollution

July 26, 2019 By EarthWise 1 Comment

We mostly think of air pollution as an outdoor problem. The primary culprits are vehicle and factory exhaust as well as occasional wildfire smoke. What we don’t think about is the air quality inside our own homes.

Researchers at Washington State University have found that indoor pollution levels can be surprisingly high and that they vary throughout the day and increase as temperatures rise.

Indoor air pollution comes from a variety of sources, including building materials, furniture, household chemical products, and from activities like cooking. One of the most serious pollutants is formaldehyde, which often is emitted from gypsum wallboard. About half of the gypsum used in homes as drywall is made from waste products from the coal industry. When the material is heated, formaldehyde and possibly even mercury can be emitted.

Pollutant levels rise in homes as temperatures increase. Thus, the highest levels of pollution occur in the afternoon and the lowest are in the early morning. Before this research, manufacturers and builders assumed that pollution levels were pretty much constant over time.

Building laws require that homes are structurally sound, and that people are comfortable, but there is little regulation of air quality in people’s homes. One of the best ways to clear out harmful chemicals is with ventilation to the outdoors. But with increased concern about reducing energy use, builders are making homes more airtight, which may inadvertently be worsening the problem.

We need to balance making more energy efficient homes with protecting our health by being aware of the dangers that lurk in the air in our homes. Running the air conditioning or opening windows are good things to do.

**********

Web Links

Researchers uncover indoor pollution hazards

Photo, posted October 14, 2010, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Breathe Better With Air Conditioning

September 15, 2017 By EarthWise

For many people, commuting to and from work is a time-consuming, stressful part of their lives. In fact, the average American spends nearly an hour a day facing traffic jams and congested highways. There are direct health hazards in commuting as well. Drivers are exposed to increased amounts of air pollutants that have been linked to a wide range of medical problems including cardiovascular disease, respiratory issues and even lung cancer.