Dry powder inhaler (DPI) � a small, handheld plastic container that contains asthma relief medications in powder form. Unlike metered dose inhalers, which require users to push down on the device to release medicine, DPI�s use a breath-activated delivery. When a patient takes a deep enough breath on the DPI, it releases the right dose. Many children under age 5 have trouble activating a DPI.

High-efficiency particulate air (HEPA) filter � cleans the air by forcing it through filtering screens. The difference between a HEPA filter and others is its level of performance. To qualify as HEPA, a filter must not release more than 3 particles for every 10,000 it captures. While many asthma and allergy patients use free-standing HEPA filters in their homes, no clinical trial has definitively proven their effects on asthma. Some experts say using a HEPA filter screen on a home air conditioner's output system provides the same level of air purity as a free-standing machine.

Metered dose inhaler (MDI) � a small plastic container that contains an aerosol receptacle of asthma medication in liquid form. Also called a puffer. When a patient presses the top of the MDI, it releases the correct dose of medication in a mist. The patient breathes this mist into the lungs. Because patients often use MDI's incorrectly, doctors recommend using a spacer. Current legislation requires all aerosol inhalers phased out by December 31, 2008. To learn more about the new, non-aerosol HFA inhalers please read the American Lung Association�s press release.

Nebulizer � an electrical medicine delivery system that turns liquid asthma medications into a mist. Patients use the nebulizer by breathing the vapor in through a mask or mouthpiece. Because nebulizers are easier to use than inhalers, doctors often prescribe them for young children. One breathing treatment on a nebulizer delivers more medicine than an inhaler does, but the treatment takes longer and is less portable than an inhaler.

Peak flow meter � small, plastic device that measures how many liters per minute (lpm) of air an individual can blow in one fast breath. Lowered peak flow readings are a good early warning signal for asthma sufferers. Keeping track of peak flow can help asthmatics determine when to use bronchodilators and can help doctors prescribe the right dosage of medicines.

Puffer - another term for inhaler.

Spacer - a small holding chamber that connects to a MDI, trapping the medicine when a patient uses the inhaler. Spacers make inhalers easier to use for children, and they also ensure more efficient medicine delivery for all users, adults and children.