How to Stop Fragrance & Smoke Coming in From Neighbors

There are a few key things you can do to prevent infiltration of fragrance, smoke, pesticides, cleaning products, and other chemicals from entering your house.

Whether the offending chemicals are coming from a neighbor with an adjoining wall in an apartment or a duplex, another house, or the outdoor air, the main strategies are similar.

The first thing that most people do (buy an air purifier), is the last thing I would do (and is not even on this list). We need to start with far more effective strategies for preventing infiltration.

Read through all the strategies and adjust them to your circumstance.

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1. Airseal Your Home

The most important thing you need to do first is to air seal.

Start by finding and sealing any small areas where air could find its way through. In an apartment, you cannot do this perfectly but you can still make an impact.

• Airseal along the baseboards wherever there is a gap or where caulking is coming loose (or was never applied) – both the top of the baseboard and bottom of the baseboard. Use AFM Caulking Compound if you want it to be paintable and neutral cure silicone (or this one from Amazon) if you don’t need it to be paintable.
• Caulk around any fixtures that are on the shared wall or the exterior walls if that is where the odors are coming in – light fixtures, fire alarms, fire sprinklers, lights, etc.
• Place gasket covers under the electrical outlets and light switch plates. These are foam gaskets that you can buy from Amazon.
• Patch any holes in the drywall with a non-toxic dry mix drywall mud (you can use premixed spackle but only if you are not that sensitive to VOCs).
• Check the caulking around windows and doors and replace it if necessary.
• Add non-toxic weatherstripping to doors if neccesary.

This is the most important step, don’t skip it.

2. Find Out if Your HVAC System Brings in Air

You want to get to know how your HVAC system works so that you can find out if it’s bringing in air, when and where it’s bringing in air, and if that air is filtered.

Some systems have fresh air intakes, some have ways for “make up air” to come in to replace exhausted air – those can be passive or active, some homes have air exchangers, known as ERVs or HRVs, which move air in and then out.

The photo on the left is a passive make up air vent with a small filter on it.

You will want to know if these systems have filters on them (and can you add or replace them), where they bring air in, and how can you control them if needed to either stop air from coming in or to control when it comes in.

The photo on the left is an ERV air exchanger which brings air in and moves air out in a balanced way. It has MERV filters on it.

3. Control Negative Pressure to Prevent Air Infiltration

Any appliance that moves air out creates a vacuum that causes air to be sucked in through any route it can find. This is usually through small leaks that are found all over most buildings. This is the main way that contaminants are getting pulled into the building.

Even if you air-sealed as much as you can from the interior side, there is only so much you can do after a home is built. Plus when you are running exhaust in any way air still needs to come back in from somewhere, so you can’t stop this from happening in unpredictable ways and locations (unless you have dedicated “make up air”, which is not very common).

Which appliances create negative pressure:

• Portable AC units that have only one hose (use a dual hose portable AC unit instead)
• Exhaust fans in bathrooms
• Exhaust fans/range hoods over the stove or microwave if they exhaust to the outside (not just those grease catchers)
• Central vacuums
• Dryers
• Some woodstoves

When you run these appliances you are essentially pulling in air through any little place it can and this causes your neighbor’s chemicals or outdoor contaminants like smoke to infiltrate the house.

To stop this from happening only run these at times of the day when the offending pollutant is not being used by your neighbors or in the community.

If that is not possible you will want to provide easy access to make up air through a window that is not on the side of the building where the fragrance, smoke, or pesticides are coming from.

If that also doesn’t work in your situation, you can consider bringing in filtered make up air (see below section).

4. Use Positive Pressure When Needed

The IQ Air Multigas has a fresh air intake (pictured above). Instead of filtering your indoor air, it brings in fresh air from outside and filters that without exhausting any air outside.

This could be used to keep out contaminants in a few ways.

If you use this without the same amount of corresponding exhausted air, you are creating positive pressure. This is pushing air out through all those cracks and crevices where those contaminants were passively or actively making their way inside.

This can work really well to keep anything from leaching in. But this can’t be used in all climates at all times of the year. Especially in the winter in cold climates, this can’t be used, as there is a risk of this causing mold behind the walls.

You could also balance this with your exhausted air. You will need to measure the CFM of both of those to balance it. What that could do is allow you to use your exhaust fans when needed but control the air that is coming in so that it doesn’t bring pollutants in through all the small cracks and crevices in an uncontrolled way, but through this one controlled location (the IQ Air).

This also ensures that the replacement air is highly filtered.

If the contaminant is in the outdoor air on all sides – like forest fires – then you might still be able to use this highly filtered outside air, especially if you do need to use your exhaust fans.

If the outdoor contaminant is something that is short-lived, like a one-time pesticide spray then I would eliminate all negative and positive pressure for that time and seal things up as well as you can.

As far as I know, you can only buy this fresh air intake for the IQ air directly through their website. I have not seen any other air purifier companies that make something like this.

Related Posts:

• How to sequester offgassing of items
• How to offgas new furniture
• How to offgas a new house
• How to mitigate and seal fragrance and smoke

Corinne Segura is a Building Biologist Practitioner with 8 years of experience helping others create healthy homes.

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