PLANTS! Here are the details from Prevention magazine. For example:

• Plants can help spark your creativity at work! A study from Texas A&M University found that people who worked for an hour in a room decorated with 2 potted plants and a bouquet of flowers generated 13% more ideas than people in a room with abstract sculptures. Why would this happen? Studies show that plants are a mood booster, and good moods are associated with higher levels of dopamine – which is the hormone that controls the flow of information throughout the brain. So if you need to feel inspired at work, try sticking small, colorful plants on your desk – like African violets.
• Plants can also help you fight colds. Dry air can lead to a parched nose and throat – which can raise your risk of infection or sinusitis. Houseplants can inject moisture back into the air and boost humidity. In fact, according to a study from the Agricultural University of Norway, people with plants in their offices reported 37% less coughing and 25% less hoarseness after three months than when they left their offices plant-free! Just make sure you pick a plant that has a lot of leaves – they release the most moisture.
• They help cut your exposure to harmful chemicals! According to botanist Kyle Wallick, when plants take in oxygen and carbon dioxide, they also pull in any toxins floating around in the air. Since all plants filter toxins from the air, just pick your favorite and stick it nearby. Also, it wouldn’t hurt to put a plant near your computer printer – it’ll help filter the toxins some of them spew.