Paint Odor

Question: I just painted the walls in my house, but I find the odor very irritating. How long will I be able to smell the paint and will it affect my health?

Answer: Different paint products use different ingredients, so it is difficult to comment on the health effects of paint in general. However, health effects associated with the paint will be significantly diminished as the paint dries. The best thing that you can do is to create conditions inside your home which would encourage a more rapid drying of the paint.

The reason you can smell the paint when it is wet, but not when it is dry, is because the ingredients that make paint liquid (usually water, oil, or solvent based depending on the type of paint) become dispersed in air as they evaporate from the painted surface. The chemical process that occurs during the drying of paint is called evaporation. Evaporation is where the liquid portion of the product changes from being a liquid to being a gas.

Just because it vaporizes doesn't mean it disappears altogether. For example, water liquid and water vapor are both still water, they just have slightly different properties. During the process of evaporation, another process occurs - dispersion. The best illustration of dispersion is when you take a bottle of cologne and open it in one corner of the room. Within a few seconds, you can smell that cologne clear across the room, even if the bottle has not been moved. That is because the cologne has changed state from liquid to gas, and then been dispersed (mixed in) with the rest of the air in the room. As the air flows through the room, it carries the odor of the cologne with it. Once you cap off the cologne (therefore removing the source), you will notice that the odor dissipates completely within a few moments. That is because as it mixes with the air in the room it becomes less concentrated and therefore your breathing in and smelling less of the cologne. This is what happens as paint dries. Eventually all of the liquid in the paint will evaporate and be dispersed, and there should be little or no odor remaining.

There are steps you can take to speed up the drying process. First, if you can wait until fall or winter, it is best to apply paint when the humidity is low. When the humidity is high, air has a harder time picking up excess moisture from paint, thus slowing the drying process. If you can't wait until there is less humidity, you could purchase or rent a dehumidifier and place it in the room which has been painted. You can also use fans to help dry paint. Fans serve several purposes. First, air that is moving has a greater capacity to pick up moisture; and second, in conjunction with open windows, fans help move the inside air to the outside where it can disperse even more rapidly, and they can help bring in fresh air from the outside. The process of moving air through a room is called "air exchange," and the more air exchanges you can accomplish, the faster you will remove the irritating odors.