The fact that straw bales are a natural product complements their energy efficiency when looking at them as the chief constituent of straw homes. Most leftover straw is simply burnt. Why not put it to more productive use and use it as a building material?  Not only will it reduce the amount of particle pollution in the air, but by using a natural building material we eliminate the process of off gassing characteristic of home construction materials like formaldehyde and volatile organic compounds (VOCs).