You Should Know


PM, Particulate matter, is the term for particles found in the air, including dust, dirt, soot, smoke, and liquid droplets. Particles can be suspended in the air for long periods of time. Some particles are large or dark enough to be seen as soot or smoke. Others are so small that individually they can only be detected with an electron microscope.

Sources of fine particles include all types of combustion activities (motor vehicles, power plants, wood burning, etc.) and certain industrial processes. Particles with diameters between 2.5 and 10 microns are referred to as “coarse.” Sources of coarse particles include crushing or grinding operations, and dust from paved or unpaved roads. Other particles may be formed in the air from the chemical change of gases. They are indirectly formed when gases from burning fuels react with sunlight and water vapor. These can result from fuel combustion in motor vehicles, at power plants, and in other industrial processes.


Volatile Organic Compounds (VOCs) are found in a wide variety of common household products: paints, varnishes, cleaning supplies, disinfectants, glues and adhesives, and even new carpet and building supplies. Look for ingredients like benzene, chloride, formaldehyde, ethylene, and toluene. VOCs can cause the following symptoms: irritation of the eyes, nose, and throat, headaches, nausea, and even severe chronic health conditions such as damage to the nervous system. The presence of VOCs can also exacerbate asthma. Like chemical cleaner vapors and aerosols, these too are more prevalent than they have been in the past.