Meet the companies tackling nine of humanity's biggest problems -- and making millions saving us from ourselves.
Problem #4: Dirty Air
Problem #4: Dirty Air
The background: Three billion households worldwide depend on wood and charcoal to prepare food, but a person cooking over an open fire that's burning wood or kerosene inhales the equivalent of the smoke from two packs of cigarettes a day. Respiratory infections are the leading cause of death in children under the age of 5 and kill 1.6 million people overall each year.

The solution: Sun Ovens International, based in Elburn, Ill., sells a family-size solar oven for $259 that's used in 130 countries. A much larger solar cooker, including a trailer and a set of pots and pans, sells for $10,500 and is designed for schools, hospitals, and orphanages. The solar oven uses mirrors to redirect the sun's rays into an insulated box.

The ovens have been popular in Haiti; the United States and Canadian militaries will use them for humanitarian projects in Afghanistan, and they'll soon be available in Uganda and Nepal.

The payoff: Sun Ovens has sold about 32,000 of its family-size ovens and 260 institutional units. Last year it generated $720,000 in revenue.

The opportunity: Sun's CEO estimates there's a worldwide market for more than 300 million family-size solar ovens, which would generate at least $75 million in revenue annually.

Global Warming

Oil Dependency

Hunger and Malnutrition

Dirty Air

Dirty Water

Overfishing

Epidemics

Drug-Resistant Infections

Waste Disposal
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Most stock quote data provided by BATS. Market indices are shown in real time, except for the DJIA, which is delayed by two minutes. All times are ET. Disclaimer.

Morningstar: © 2014 Morningstar, Inc. All Rights Reserved.

Factset: FactSet Research Systems Inc. 2014. All rights reserved.

Chicago Mercantile Association: Certain market data is the property of Chicago Mercantile Exchange Inc. and its licensors. All rights reserved.

Dow Jones: The Dow Jones branded indices are proprietary to and are calculated, distributed and marketed by DJI Opco, a subsidiary of S&P Dow Jones Indices LLC and have been licensed for use to S&P Opco, LLC and CNN. Standard & Poor's and S&P are registered trademarks of Standard & Poor’s Financial Services LLC and Dow Jones is a registered trademark of Dow Jones Trademark Holdings LLC. All content of the Dow Jones branded indices © S&P Dow Jones Indices LLC 2014 and/or its affiliates.