Published: April 3, 2020

Shelly MillerHow can you keep your indoor air quality healthy if you’re stuck at home amid a global pandemic?

Professor Shelly Miller of the Paul M. Rady Department of Mechanical Engineering and the Environmental Engineering Program has been tackling these and other questions in her Fundamentals of Environmental Engineering class. Here she addresses some common questions posed by students.

Miller is also part of a free, online panel titled “Our Health Post-Coronavirus: A New Frontier” at 2 p.m. Friday, April 10. The talk, part of the Conference on World Affairs, will be conducted via zoom. Visit the CWA webpage for more information.

Q: How can people who live in cold climates (like myself) combat indoor air pollution, especially during a time like this where people are spending the majority of their time inside? It’s been snowing for the past two days where I live.

It is so tough in the winter. Minimizing sources of air pollution inside is the main thing. The biggest source is typically cooking, especially with natural gas stoves, so use your exhaust hood all the time when cooking. Cook over lower heat, too. If you don’t have an exhaust hood that exhausts directly outside, you can and should open a window, or you can leave on your bathroom fans, but this will typically cause more cold air to leak into your home and you will need heat more. Make sure to take off your shoes indoors; it also helps to have track mats at each door. When cleaning, use simple products with 60% alcohol and fragrance free (if you can find them!)

Q: How are indoor air quality levels monitored and maintained? Should I be paying attention to the levels of lead and bioaerosols in addition to the carbon monoxide that we monitor? Can changing my choices as a consumer (non-flame-retardant furniture, no aerosols, electric stove) lead to lower levels of indoor air pollutants?

The main source of lead in a home is paint, and you may find this kind of paint in homes that are older than 1978. If your home is newer, there should not be lead paint. Here is what the EPA says about this topic: Lead Paint. As long as you do not disturb the paint, which will typically be under layers of newer paint, and if it is in good shape and not flaking off of surfaces, it should be OK. However, it can get in the dust if it is flaking or peeling.

Some main bioaerosols of concern in homes are indoor allergens: dust mites, pet allergens, cockroaches, indoor and outdoor molds. If you do not have allergies or asthma, then bioaerosols are typically not a worry, except of course these days when we have this highly infectious virus spreading around. Which is why we should all be staying home – a selfless act to protect public health and for the greater good – so make sure you wash your hands and do everything the CDC recommends. 

You can definitely change your consumer habits and reduce toxic sources in your home. You can purchase non-flame retardant furniture, buy fragrance-free household products, minimize carpeting in your home, do not purchase textiles treated with PFAS, and use your exhaust hood while cooking.

Q: Now that my family is all inside the home, how do we minimize indoor air pollution (not just spread of viruses, but also other hazards like carbon monoxide). I live in a fairly old home, so our ventilation system is not very good – should we be changing our air filters more? Do those air filters in homes really help at all?

Older homes are typically leakier, which is actually a good thing. That means more outside air can leak into and out of your home if there is a pressure/temperature differential between indoors and outdoors. Your air exchange rate will be higher, more like 1 air-changes-per-hour (1 ach), compared to a tighter home that has a lower air exchange rate (like 0.2 ach).

To increase ventilation you can leave on bathroom fans and also use your stove exhaust hood a lot (as long as they vent directly outdoors), especially when cooking. You can also leave on your whole house fan to run continuously and, yes, change the filters more often. The filters do help; they are typically not very efficient but better than nothing. There is not much evidence that running a whole house fan will improve indoor air quality, but it does mix your indoor air and run it through a coarse filter, so it might be beneficial – we need more research here! You could also upgrade to an electric filter or purchase an air cleaner. And make sure you have a CO alarm.