cooking

Pulling Water From The Air

October 14, 2019 By EarthWise Leave a Comment

A couple of years ago, we reported on the early development of a device that harvests water from the air that even works in the low humidity environment of a desert. Since then, the researchers from UC Berkeley have continued to improve the device and it is now 10 times better than it was two years ago.

The harvester is based on a porous water-absorbing material called a metal-organic framework, or MOF. The latest version can pull more than five cups of water from low-humidity air per day for every kilogram of the improved MOF material and that is more than enough water to sustain a person. The harvester cycles around the clock and is powered by solar panels and a battery.

Previous techniques for condensing water from air at low humidity required cooling down the air to temperatures below freezing, which is not economically practical. The MOF-based device does not require any cooling.

The Berkeley researchers have formed a startup company – Water Harvester, Inc. – which is now testing and will soon market a device the size of a microwave oven that can supply 7 to 10 liters of water per day, which is enough drinking and cooking water for two or three adults.

An even larger version of the harvester, which would be the size of a small refrigerator, would provide 200 to 250 liters of water per day, enough for a household to drink, cook, and shower. The new company envisions a village-scale harvester that would produce 20,000 liters per day, still running off of solar panels and a battery.

Water Harvester believes the water needs for many people can come out of the thin air.

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Water harvester makes it easy to quench your thirst in the desert

Photo courtesy of Grant Glover (University of South Alabama) via UC Berkeley.

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.

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Researchers uncover indoor pollution hazards

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

Earth Wise is a production of WAMC Northeast Public Radio.

Meal Kits And The Environment

June 11, 2019 By EarthWise Leave a Comment

Meal kit services have become extremely popular in recent years. These are companies that deliver a box of pre-portioned ingredients and a chef-created recipe to your door to make home-cooked meals easy and practical for busy people. Leading companies like Blue Apron, HelloFresh, and Plated have been joined by dozens of others competing in the meal kit market. As of last year, annual sales for these things were over $3 billion and growing at more than a 20% annual rate.

A major rap against meal kits has been their environmental impact, mostly centered around the amount of packaging waste they generate. While there is most certainly lots of packaging waste associated with meal kits, it turns out that their overall carbon footprint is actually rather good compared with conventional ways to make homecooked meals.

A study from the University of Michigan looked at the cradle-to-grave impact of meal kits, taking into account every major step in the lifetime of the food ingredients and the packaging – agricultural production, packaging production, distribution, supply chain losses, consumption, and waste generation.

Surprisingly, meal kits have a much lower overall carbon footprint than the same meals made from ingredients purchased at the grocery store – even including their packaging. The main reason is that pre-portioned ingredients and a streamlined supply chain lower overall food losses and waste for meal kits compared to store-bought meals. Pre-portioning simply results in fewer ingredients that end up being wasted. Meal kits also have radically different supply chain structures than foods sold in supermarkets.

Whether the economics and culinary aspects of meals kits are advantageous for many people is an open question, but apparently from an environmental perspective, they are just fine.

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