ongoing operations. Office paper, light bulbs, automobiles, furniture, and cleaning supplies are just a few examples of items regularly purchased by state governments.

By procuring and using environmentally preferable products and services, state governments have the perfect opportunity to substantially reduce the environmental impact of their own buildings and operations. Perhaps more importantly, in so doing states also demonstrate environmental leadership, increase public awareness of the benefits of buying green products, and encourage economic development of greener goods by fostering markets for environmentally preferable products.

Increasingly, state governments have identified green cleaning as a key strategy in achieving their sustainability objectives. As a result, 22 states have now adopted a green cleaning procurement policy of some kind. Historically, these state green cleaning laws and policies have focused on state agencies or state-owned buildings.

\section{Developments in State Green Cleaning Policies for Schools}

During the last five years or so, states increasingly focused on implementing green cleaning in K-12 schools, primarily because the children who are in these buildings every day are an especially vulnerable population. Ten states plus the District of Columbia now require or encourage schools to adopt green cleaning programs, and that number will continue to grow as information about such policies and programs becomes more readily available and other states emulate those that have gone before them.

These laws and policies on green cleaning in schools share several features. For example, they recognize the importance of high performance cleaning as necessary to maintain a sanitary and healthy indoor environment that is important for students' short- and long-term health---and that is ultimately conducive to student performance. In fact, there is a growing body of evidence that shows a positive correlation between student academic performance and the state of ``cleanliness'' within the school facilities.

At the same time, state policies on green cleaning also recognize that we can perform highly effective cleaning that removes harmful microorganisms, infectious agents, allergens, and other deleterious substances in an environmentally benign manner given the new products, technologies and processes that are available today. Moreover, given the state of today's marketplace, schools can transition to a comprehensive green cleaning program without adversely affecting their budgets. Indeed, many schools have experienced cost savings after switching over to an environmentally preferable cleaning program.

However, state policies vary considerably. Most laws require schools to use green cleaning products, but differ in how they establish criteria for meeting this requirement. Laws in New York and Illinois, for example, direct the state to adopt guidelines and specifications that schools must use in purchasing green cleaning products. In Connecticut and Iowa, such guidelines are not required, but schools must use products that meet third-party certification standards and/or are approved by the state. By contrast, Maryland law leaves it to each school district to adopt its own specifications for purchasing green cleaning products. Moreover, two state laws (Maine and Missouri) do not mandate green cleaning, but rather direct the state to develop voluntary green cleaning guidelines that school districts may elect to use.

\begin{figure}[h]
\centering
\includegraphics{figure_1.pdf}
\caption{Implementing Green Cleaning Programs in K-12 Schools. Connecticut, District of Columbia, Hawaii, Illinois, Iowa, Maine, Maryland, Missouri, Nevada, New York, and Vermont.}
\label{figure_1}
\end{figure}