have the wherewithal - prepare your home for vacation &
leave until it's safe to come back. Arrange to meet your
homeowner's insurance requirements for an unoccupied home.
can't leave, prevent outdoor air from entering your home;
close windows, doors, and shut down any systems connected to
the outdoors (ex. portable a/c units). You may have to be
creative so use what resources you have or can buy or
borrow. If you are unable to develop creative solutions ask
a family member, friend, neighbour or hire a tradesperson.
are outdoor air intakes/ducts (sometimes called fresh air
ducts) connecting the outdoors to your air systems (furnace,
a/c, HRV/ERV, central vac etc.) block them (don’t close any
damper unless you know how to return the damper to its
original positions)...same for wood burning fireplaces and
stoves seal up/block so there is no connection between the
indoors and outdoors....take pictures to remind yourself
what you have done...so you can return the system to its
previous state when it's safe. If you don't know if you have
an outdoor air duct(s), this would be a good time to hire an
HVAC contractor to explain the system(s) you have.
individuals living in spaces conditioned with electric,
steam or hot water systems may or may not have separate
ventilation systems. If you do live in spaces with these
types of systems, and have an independent ventilation system
follow the same advice for those with furnaces and outdoor
air intakes/ducts. Your spaces may be of a vintage that had
no ventilation system; that is no fans to exhaust indoor air
from the home and no fans to bring outdoor air into the
home. In these vintage homes typically windows and building
enclosure leakage was relied upon for ventilation. Do your
best to seal up leakage paths.
live in an older condo or apartment there is a high
probability that outdoor air could be introduced to the
common hallways unless the building operator shuts off the
air handling systems. Block the airflow under and around the
door with a towel and tape.
have an option to set your furnace fan to recirculation - do
so...ensure the duct fitted air filter (located before the
furnace intake) is MERV 13+ or the equivalent to the 3M
1900+ series...lower performing filters (<MERV 8) can
recirculate smoke particles throughout your home eventually
settling onto surfaces which will then be disturbed by the
movement of occupants and pets. If you have the wherewithal,
have a carbon based filter
installed after the particulate filter to help remove some
combustion related gases. Follow the manufacturers recommend
guidance for replacement.
sustained use of exhaust fans including kitchen, bath,
clothes dryer, and central vacuum systems. These have the
potential to pull smoke into the home through leakage
pathways such as windows, doors, and duct work connected to
the outdoors etc.
you can all heat generating devices and
activities...exercising, cooking, cleaning, laundry plus
computers, TV's etc... until it is safe to open windows or
operate A/C and exhaust fans. Adding heat to home is never
good when it's already hot and smoky outside and cooling and
clean air is needed inside - but not available.
filtration such as the Corsi-Rosenthal Box are your
friend...use them. MERV 13 or 3M 1900 or better is the
minimum. Have replacement filters on hand. Some have
installed MERV 13+ filters in window openings to enable
outdoor air to enter the home filtered (in part) before
being drawn into the in-space filter units.
Relocate to a basement. Basements are often better isolated
from the outdoors than above grade rooms...and they will be
respirators for added protection...don’t use the typical
blue surgical masks handed out at hospitals - they do not
provide a face seal...i.e. they leak. You can purchase N95
online or at DIY building supply store. If you are at risk
due to exposure of smoke particles and gases follow the
respirator guidance from 3M, see <
worsening situation, if possible, isolate yourself in a
single smaller room in the basement...bring with you
in-space filtration & masks. All things being equal, a Corsi-Rosenthal
Box in a small room will be more effective than in a larger
have CO2 monitors - keep an eye on them...don't panic if
they run high <3500 ppm...use any opportunity of clean
outdoor air to ventilate your rooms. This frequently happens
when the wind changes direction or fire crews have
redirected fires or fires have been controlled through
intervention or natural suppression (rain).
are sensitive to elevated CO2 >1000 ppm follow (if possible)
a strategy of moving between two rooms (airlock technique
c/o Thekla Richter). One room is being ventilated outdoors
to drop CO2 down, then isolated and then cleaned with a
combination of MERV 13+ (equal to 3M 1900+) and activated
charcoal filters. Once the CO2 is below an ideal 800 ppm
then move into the clean room and repeat cleaning on the
vacant room. If you are not able to make this strategy work,
wear specialized masks and cartridges recommended by 3M. See
Figure 6 from our isolation page for an ideal case where
two bedrooms share a common bathroom. Isolate one room and
ventilate to outdoors using bath fan and open window, then
reverse the process. Occupy the room that has been
ventilated and cleaned.
are at elevated risk (elderly, infirm, asthmatic etc.) let
neighbours, family and friends know and call your family
physician and let them know - before you become stressed.
know someone who is high-risk do the right thing and help
are several newer public places that may offer relief such
as recreation centers, shopping malls, movie theatres etc.
is a corresponding heat wave get below grade on the north
side of a building and elevate the air speed with air
filters, if necessary, wear saturated towels wetted with
cold tap water...remain calm, reduce your exertion levels,
wear light clothes and stay hydrated...follow guidelines for
the fatalities in BC's recent heat wave died indoors...when
emergency response was overwhelmed due to the number of
calls...many could have survived had the above been
initiated with help from emergency services, neighbours,
friends and family...this includes taking cool baths or
wearing saturated wet towels in elevated air speeds (fans –
ceiling, floor, desk).
stay hydrated. The ability for one's body to cool is
intimately tied to the heart's ability to pump blood and is
based on the bloods viscosity (think honey vs. water). A
dehydrated body puts stress on the cardiovascular system
preventing adequate cooling and respiration.