Show me anything, and I’ll investigate it. This investigation was spurred by an article blurb I reviewed for a potential spot in AESP’s monthly member e-magazine, Strategies. The headline: Connection Between Home Energy Efficiency and Respiratory Health in Low-Income Homes. That sounds fine enough until I got to the reported root cause: too much infiltration; i.e., ventilation; i.e., fresh air! The study says people living in drafty homes have higher rates of chronic cough, asthma, and asthma-like symptoms.
I find it amazing how numerous topics I’ve written in the past converge into a topic like wasting energy via infiltration reportedly degrades health. How? I can only guess, but the symptom found more frequently in homes with high infiltration rates was higher asthma rates. How can this be? Unless your job includes managing a machine shown below (harvesting soybeans in Iowa), the air indoors is not cleaner or better than what is outdoors.
Next, I investigated air quality in the test area: Denver, Aurora, Boulder, Loveland, and Fort Collins. Who knew these places had squalid air quality? It could be that inversion layers trap smog and ozone. An inversion layer creates a boundary between upper elevations and city-level elevations. This causes brown bubbles of air over cities like Salt Lake City, Los Angeles, and New York. Are the cited test locations in Colorado that bad?
Compare Your Air
Introducing, The American Lung Association’s Compare Your Air. I found this in an effort to see how awful Denver’s air quality is. Indeed, Denver’s air is horrible, according to the Lung Association – but so is every other major city, as shown in the following table.
Still more complexing, per the chart below, the rates of various ailments among the cities are similar, except, Denver, Aurora, et al., have statistically significant lower rates of these ailments.
For the Lung Association, somehow the ozone and particulate grades are not translating to ailments. For the authors of the underlying study for this post, I would say some things far exceed the effects of infiltration/ventilation. The subjects of observable and unobservable factors, as described in Unmasking the Randomized Control Trial, come to mind.
Eyes need to open to see observables. The observables I see are that despite the Lung Association’s poor air quality grades for Denver, the population is demonstrably healthier than in other cities around the country. Ailment rates in Denver might be on par with the ailment rates in the other cities. There is one observable question, at least.
Other than that, we have the second law of thermodynamics, which tells us that in the absence of energy input, in this case, to clean the air, outdoor air when introduced to an indoor space gets dirtier. In hospitals, for example, fresh air flows from clean, fresh outdoor air (e.g., surgery or ICU) to dirty (bathrooms, kitchens, or laundry). I.e., things get worse with no energy input. The vast majority of maintaining indoor air quality in buildings is done by introducing sufficient outdoor air into occupied spaces.
How is outdoor air cleaned? Good luck finding much on that, but I do know this: the catalyst to form every raindrop and snowflake is a speck of dust. The energy input: the sun.
There are also zillions of microbe species that have evolved to digest practically any pollutant. For instance, although it wasn’t my bag at the time, Michaels used to engineer (verb) cleanups for underground petroleum plumes. Toward the end of the run, it was realized that microbes are more cost-effective than humans cleaning soil. We merely needed to pull the leaking tanks to stop the flow. Microbes took care of the mess.
I think everyone remembers the British Petroleum deep-water horizon geyser a few years ago. Microbes handled the vast majority of the cleanup. Microbes will even devour nuclear waste – something I read a long time ago, and I see in this more recent article, is that they consume waste faster than previously thought.
The name of the game is don’t overwhelm the system with pollutants. Nature, that is, things that happen outdoors, does a remarkable job of cleaning the air, water, and soil. Except for some of the most expensive, energy-intensive, manmade vehicles like spacecraft and submarines, any occupied, manmade, hermetically sealed environment is not going to be cleaner than ambient outdoor air.
I’m all for efficiency of course, but if there is a direct correlation between infiltration in isolation of other factors, and worse indoor air quality, I’ll eat crow for a year. It might taste good with the right recipe.
I like learning and correlating anything, but asthma has the least correlation to anything I’ve ever seen, as demonstrated in this report by the Asthma and Allergy Foundation of America. Finding #1: of the largest 100 cities in the country, McAllen, Texas, is the poorest, least insured, most pollinated, with the fewest specialists, AND it has the lowest asthma rate in the country. The twenty cities with the highest poverty rates have asthma rates that are inversely related (less poverty, more asthma). The chart below represents asthma rank (best = 100) versus the highest rate of poverty (poorest on the left). The results appear to have come from a random number generator.
Conclusion: more data and analysis required.
 Lines represent weighted average rates for all cities shown.