Air quality readings during my trip to Puerto Rico

A photograph of a CO2 meter on my lap reading 2,074 ppm while deplaning in Puerto Rico, showing the poor air quality on the plane Air quality has a significant effect on human health. During the COVID-19 pandemic, it has become an especially critical issue. Why? Because COVID-19 spreads via aerosols that can float in the air for minutes to hours. Although there is currently no commercially available way to measure the presence of COVID-19 in the air, I’ve written about how measuring carbon dioxide (CO2) concentrations can act as a useful proxy for COVID-19 infection risk. Small, inexpensive CO2 meters are now widely available.

So when I took a deep (masked) breath and decided to accept an invitation to design and lead a two-day meeting industry leadership summit in Puerto Rico, I decided to bring my CO2 meter with me. What would I learn about the air quality in the airports, planes, and ground transportation I used, as well as my hotel and the summit’s convention center? Well, I uncovered significant air quality concerns in places that may surprise you. Read on to find out what I discovered. But first, a brief explanation of what CO2 measurements mean.

How do CO2 levels correlate with the risk for COVID-19 infection?

It’s complicated! Measurements of indoor COconcentrations can often be good indicators of airborne infection risk. But clear conclusions on the CO2 level corresponding to a given COVID-19 infection risk are currently lacking. Multiple factors influence the risk. These include exposure duration, the mixing of air in the vicinity, the exhalation volume and rate of infected individuals, and, of course, the use of masks, virus-removing air filtration, and UVC and far-UVC radiation. This article gives some idea of the complexities involved. The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has summarized current thinking on indoor CO2. ASHRAE takes the position that “indoor CO2 concentrations do not provide an overall indication of IAQ [indoor air quality], but they can be a useful tool in IAQ assessments if users understand the limitations in these applications.”

More research is required, especially because of “the ubiquity of indoor concentrations of CO2 in excess of 1,000 [parts per million] ppm.” And ASHRAE reports that “indoor concentrations of CO2 greater than 1,000 ppm have been associated with increases in self-reported, nonspecific symptoms commonly referred to as sick building syndrome symptoms.” To summarize, currently, there is insufficient research suggesting CO2 levels that indicate a significantly increased risk for COVID-19 infection. However, many authorities have tentatively proposed maximum levels of around 1,000 ppm CO2 as guidelines.

air quality
From a REHVA (The Federation of European Heating, Ventilation, and Air Conditioning) journal article on CO₂ monitoring and indoor air quality.

OK, enough of this; you probably want to know what I found. Here we go!

Flying

I flew JetBlue flights 261 and 462 between Boston (BOS) and San Juan (SJU). My outbound flight, on an Airbus A321, lasted 3 hours and 43 minutes. My return flight, on an Airbus A320, took 4 hours and 40 minutes. (Don’t ask.) On both flights, I had an aisle seat in row 15. As you can see from the photo at the top of this post, I perched my little CO2 meter on my knees when tray tables had to be up. The rest of the time, it nestled perfectly into the little tray table drink recess. Here’s an annotated graph of the CO2 readings I took on my outbound flight. Air quality plane

My key flight observations

  • Boarding the aircraft led to a large spike in CO2 levels. Levels increased sharply in the jetway as I approached the passenger door. Slowly walking down a packed aisle to my seat I saw readings around 2,000 ppm. Once in my seat, the levels dropped somewhat but were still high (1,600 ppm) when they closed the door.
  • Levels stayed high (above 1,500 ppm) while taxiing until we took off. We had been on the plane for about 50 minutes at this point.
  • I estimate that about 30% of the passengers were unmasked, as well as most of the flight attendants.
  • During the cruising portion of the flight, the CO2 level stayed at REHVA’s “upper range of reliable air quality” of 1,000 ppm. The level in the bathroom was 1,200 ppm.
  • Once we started our descent, levels rose a few hundred ppm. On landing, we were at 1,300 ppm.
  • During deplaning, levels soared again. I took the photo at the top of this post, showing a reading of 2,074 ppm, at this point.
  • As soon as they opened the passenger door, levels dropped to around 1,200 ppm.
  • On my return trip (which took close to five hours) I saw similar readings, except that:
    • The cruising flight COlevel was significantly higher (1,200 – 1,400) ppm.
    • The boarding peak was lower (1,500 ppm).
    • The deplaning peak was an unsettling 2,400 ppm.

To summarize, these readings are troublesome. Aircraft ventilation systems reportedly filter out aerosols, assuming that the HEPA filters are regularly replaced. However, the close proximity of passengers (both flights were full) still allows people to infect others close to them, as this NY Times article illustrates. The high readings I saw indicate that in-flight ventilation was not fully operative during embarkation and deplaning on either flight. I am glad I wore a high-quality N95 mask during both.

Airports

BOS airport levels were around 600 ppm. At SJU I saw readings between 650 – 800 ppm. Both of these are acceptable. Neither airport was especially crowded, however, and I would be cautious about assuming it’s OK to go unmasked there.

Ground Transportation

This was a shocker to me. In the U.S. during the pandemic, when driving with others I’m used to having the car windows open, at least a little. Puerto Rico was hot and humid, and the vehicles I was in had the A/C on and windows closed. My client had arranged a car and driver to pick me up from the airport and drive me to the convention center for a couple of technical rehearsals and then to my hotel. Just the two of us in a Chevy Suburban quickly raised the CO2 level to around 1,500 ppm for the 30 minutes we were together. Luckily we were both masked.

I saw the same readings during my trip to the airport at the end of the event.

But I saw the highest readings during my travel in a shuttle bus bringing us to the opening reception. There were, perhaps, 20 of us on board. Readings spiked to over 3,000 ppm! And some of the passengers were unmasked.

The conference center

The conference center was far from maximum capacity and I only saw readings well below 1,000 ppm. We held the summit in four meeting rooms with high ceilings. We left the meeting room doors open, and my meter typically showed readings between 500 – 600 ppm. If the venue had been packed or the doors closed it might have been a different story.

My hotel

I was concerned about the air quality in my (large) hotel room because I expected it to have no openable windows due to San Juan’s climate, and this proved to be the case. Over the three nights I was there I noticed the same pattern. On entering the room during the day, readings were about 600 ppm. As evening approached, the readings slowly climbed to about 900 ppm.

I had reason to be concerned.

The increase in CO2 as evening approached was probably due to increased occupancy of nearby rooms. Building heating, ventilation, and cooling (HVAC) systems typically recirculate interior air, mixing together air from all the rooms in the building. So as guests retire to their rooms in the evening, the overall CO2 concentration in every room increases.

That means that although I was alone in my room I was breathing exhalations from other guests. If any of those guests had COVID-19, it’s possible that their aerosols would travel into the air I was breathing. There was nothing I could do to protect myself other than wearing a mask the whole time I was there (which obviously included sleeping!)

Commercial HVAC systems

Commercial HVAC systems include filters to remove dust and dirt. Typical HVAC filters will not stop COVID-19 aerosols unless they have been upgraded to MERV 13 or better (e.g. HEPA). They also need to be regularly replaced to work correctly.

Whether these mitigation measures have been performed at a hotel is hard to know. My hotel was modern, but that doesn’t mean its HVAC system was well-designed and safe. I have stayed at hundreds of hotels over the years. Some of them, based on the odor of the rooms, had ventilation problems of some kind. Paradoxically, the single-unit heating and cooling systems common in inexpensive lodgings could be safer because air entering the room only comes from outside.

Concerns like these have made me cautious about staying in accommodations that don’t have windows that can be opened. That wasn’t possible in Puerto Rico, and my CO2 monitor gave me at least some reassurance that air quality levels weren’t too bad. However, many commercial lodging offerings don’t offer this option. The inspection and, if necessary, re-engineering of hotel HVAC systems is an important step to protect guest health. Yes, it costs money, but if the owners have done this work they should publicize it as a reason to stay.

For more information about this important topic, read my article about COVID-19 transmission and air quality in buildings.

Conclusion

As I write this, I’ve been isolating for four days since my return and just performed my fourth daily rapid antigen test. All have been negative. So it looks like I’ve escaped getting COVID-19 during my first major travel since the pandemic began. I recommend travelers purchase an inexpensive CO2 meter and bring it with them.

I hope the information I’ve shared in this post is helpful in warning other travelers of potentially dangerous environments. COVID-19 is far from over. As the pandemic continues, monitor your air quality while traveling—and mask up.

Travel safe!

Venue ventilation for COVID-19

venue ventilation COVID-19: an illustration of a wall vent with air and question marks swirling outAttention, meeting planners! Safe meeting venue ventilation for COVID-19 is critical. As we start thinking about returning to in-person events, it’s crucial to check that venues are upgrading their HVAC systems to handle potentially virus-infused air.

There has been little public discussion on this important topic. In this post, I’ll explain why questions about venues’ HVAC safety should be at the top of your site visit checklist.

Before we start, I need to make clear I’m not an HVAC engineer. My (perhaps) relevant background is an ancient Ph.D. in high-energy particle physics. I also spent two years spent exploring ventilation systems—specifically air-to-air heat exchangers—when I owned a solar manufacturing company in the 1980s.

Introduction

Since the pandemic began, the science of COVID-19 transmission has evolved rapidly. Because early theories turned out to be inaccurate, current preventative measures are frequently misdirected. So I’ve included a short history of theories of COVID-19 transmission. These shed light on the reasons we’ve underestimated the importance of ventilation in creating safe environments for indoor events.

Next, I’ve outlined what current research indicates venues and properties should be doing.

Finally, I’ve aired my concerns about how well venues and properties are responding to the safety concerns I’ve introduced.

A short history of theories of COVID-19 transmission

Initial focus on surface contamination

Early reports on SARS-CoV-2 virus transmission falsely concluded that surface contamination was a significant transmission vector.

“COVID-19 is transmitted via droplets and fomites during close unprotected contact between an infector and infectee. Airborne spread has not been reported for COVID-19 and it is not believed to be a major driver of transmission based on available evidence.” [Emphasis added]
Report of the WHO-China Joint Mission on Coronavirus Disease 2019 (COVID-19), February 2020

This led to an epidemic of another kind—regularly cleaning and disinfecting surfaces. Meeting industry venues that have remained open during the pandemic adopted cleaning and disinfecting everything in sight as a visible assurance that their venues were safe places to gather.

“By May, [2020] the WHO and health agencies around the world were recommending that people in ordinary community settings — houses, buses, churches, schools and shops — should clean and disinfect surfaces, especially those that are frequently touched. Disinfectant factories worked around the clock to keep up with heavy demand.”
COVID-19 rarely spreads through surfaces. So why are we still deep cleaning?, Dyani Lewis, Nature, January 2021

However, current research suggests that the risk of infection from touching a heavily contaminated surface is less than 5 in 10,000. This is considerably lower than current estimates for SARS-CoV-2 infection through aerosols.

Despite this information, the current GBAC STAR™ Facility Accreditation Program for Cleaning, Disinfection, and Infectious Disease Prevention Accreditation Handbook concentrates on cleaning and disinfecting surfaces. The handbook barely mentions venue ventilation for COVID-19. The International Association of Venue Managers (IAVM)’s Public Assembly Facilities Recovery Guide (October 2020) has a section on HVAC systems, but still provides much more detail about cleaning and disinfecting.

By the way, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends that cleaning activities be performed after hours, rather than during meetings because “Vacuuming, sweeping, curtain cleaning, brooms, could potentially re-suspend infectious particles.” [ASHRAE Epidemic Commercial Task Force recommendations, updated March 2021, Page 10.]

Droplet transmission

After scientific consensus quickly moved to droplet transmission as a significant factor, face masks were strongly recommended, and mandated at most in-person meetings. However, there have been numerous reports of lax mask usage during F&B breaks and socials.

Social distancing was also recommended. Why? Because it was thought that the COVID-19 virus was mainly transmitted via large respiratory droplets that fall quickly. This belief is still popular and frequently cited today.

Airborne transmission

Unfortunately, the latest research now points to aerosol transmission of COVID-19 as a significant vector. Aerosols are small droplets and particles (formed when small droplets dry quickly in the airstream) that can remain suspended for many minutes to hours. They can travel far from the source of air currents. An excellent summary of this research is included in The Lancet‘s April 15, 2021 article: Ten scientific reasons in support of airborne transmission of SARS-CoV-2. Here’s the key introductory paragraph:

If an infectious virus spreads predominantly through large respiratory droplets that fall quickly, the key control measures are reducing direct contact, cleaning surfaces, physical barriers, physical distancing, use of masks within droplet distance, respiratory hygiene, and wearing high-grade protection only for so-called aerosol-generating health-care procedures. Such policies need not distinguish between indoors and outdoors, since a gravity-driven mechanism for transmission would be similar for both settings. But if an infectious virus is mainly airborne, an individual could potentially be infected when they inhale aerosols produced when an infected person exhales, speaks, shouts, sings, sneezes, or coughs. Reducing airborne transmission of virus requires measures to avoid inhalation of infectious aerosols, including ventilation, air filtration, reducing crowding and time spent indoors, use of masks whenever indoors, attention to mask quality and fit, and higher-grade protection for health-care staff and front-line workers. [Emphasis added.]

How to think about aerosols

You can think of COVID-19 aerosols as cigarette smoke, or the aroma from cooking food. Of course, aerosols diffuse over distance, which is why social distancing is still a good idea, and why transmission of COVID-19 outdoors is unlikely unless people are tightly packed together. Incidentally, this means that if you’re eating or drinking at a restaurant or bar and can smell the food of diners at a nearby table or the smells of cooking from the kitchen, you’re not in a safe situation as far as COVID-19 transmission is concerned.

Pre-pandemic building ventilation standards are inadequate for COVID-19

Interim guidance published by the California Department of Public Health points out that standard building environments have not been engineered to control exposures to small aerosols of hazardous viruses, such as COVID-19:

“Our understanding of the role that the built environment plays in the transmission of COVID-19 is evolving; recent literature has clearly demonstrated small aerosols can be carried well beyond the six (6) foot physical radius and remain suspended in room air where they can be inhaled. With the possible exception of hospitals, healthcare facilities, and research facilities that employ exhaust hoods, existing ventilation requirements, such as those established in the California Building Code and Title 24, were not intended to control exposures to small aerosols of hazardous infectious agents such as COVID-19.” [Emphasis added]
—General Considerations extract from the Interim guidance for Ventilation, Filtration, and Air Quality in Indoor Environments, California Department of Public Health, February 21, 2021

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) points out that many existing mechanical air filters will not remove enough levels of airborne COVID-19:

ASHRAE recommends that mechanical filter efficiency be at least MERV 13 and preferable MERV 14 or better to help mitigate the transmission of infectious aerosols. Many existing HVAC systems were designed and installed to operate using MERV 6 to MERV 8 filters. While MERV 13 and greater filters are better at removing particles in the 0.3 micron to 1 micron diameter size (the size of many virus particles) the higher efficiency does not come without a penalty. Higher efficiency filters may require greater air pressures to drive or force air through the filter. Care must be taken when increasing the filter efficiency in an HVAC system to verify that the capacity of the HVAC system is sufficient to accommodate the better filters without adversely affecting the system’s ability to maintain the owner’s required indoor temperature and humidity conditions and space pressure relationships.” [Emphasis added]
ASHRAE Epidemic Taskforce Building Readiness (updated March 16, 2021)

Updating HVAC systems is not plug and play

The above ASHRAE guidelines explain that you cannot simply swap existing filters with MERV 13 or better filters and pronounce your building “ready” to handle potentially COVID-19 infected people. Venues and properties will typically need to involve “licensed and certified professionals and companies that can perform the analysis, testing, design, construction, control programming, balancing, commissioning, maintenance and operation services required to make the adjustments and achieve the performance included in these recommendations.”

Major heating plant upgrades may be needed to create safe air quality for occupants.

Reopening unoccupied buildings

Finally, many properties and venues have been operating in low-occupancy mode for long periods. Reopening such buildings safely, even to pandemic-appropriate occupancy levels, can require several weeks of preparation for the HVAC plant and facility staff. Here is what the Centers for Disease Control and Prevention (CDC) recommends be done before resuming business operations:

  • Evaluate the building and its mechanical and life safety systems to determine if the building is ready for occupancy. Check for hazards associated with prolonged facility shutdown such as mold growth, rodents or pests, or issues with stagnant water systems, and take appropriate remedial actions.
  • Ensure that ventilation systems in your facility operate properly. For building heating, ventilation, and air conditioning (HVAC) systems that are shut down or on setback, review new construction startup guidance provided in ASHRAE Standard 180-2018, Standard Practice for the Inspection and Maintenance of Commercial Building HVAC Systems.
  • Increase circulation of outdoor air as much as possible by opening windows and doors if possible, and using fans. Do not open windows and doors if doing so poses a safety or health risk for occupants, including children (e.g., a risk of falling or of breathing outdoor environmental contaminants such as carbon monoxide, molds, or pollens).
  • To minimize the risk of Legionnaires’ disease and other diseases associated with water, take steps to ensure that all water systems and features (e.g., sink faucets, drinking fountains, decorative fountains) and water-using devices (e.g., ice machines, cooling towers) are safe to use after a prolonged facility shutdown.

COVID-19 Employer Information for Office Buildings, CDC, updated April 7, 2021

What are meeting venues doing to create safe ventilation?

I’m concerned about the lack of visible venue and property efforts to resolve the ventilation safety issues caused by COVID-19.

Over the last couple of months, I’ve reached out to industry contacts and meeting professionals on social media. I’ve asked for examples of venues and properties that have implemented (or are implementing) ventilation upgrades that will satisfy recent interim comprehensive guidelines such as those published by ASHRAE and the California Department of Public Health.

To date, I have heard of only one venue—a California hotel property that installed MERV 13 filters. If your venue has made or is making such upgrades, please let me know, either directly or via comments on this post.

Perhaps many venues are quietly making these changes. I hope that’s the case.

Perhaps some venues are ignoring the problem, hoping that, somehow, the COVID-19 pandemic will disappear, and they’ll be able to host in-person events without updating their HVAC plant. I doubt they’ll be so lucky.

Frankly, I’m surprised that those who have updated their venue ventilation for COVID-19, aren’t publicizing this as a competitive advantage. Our industry is yearning for the return of in-person meetings. Being able to say a property is compliant with current ventilation guidance seems like a great selling point. This article from the Washington Post (kindly shared with me by Joan Eisenstodt) exemplifies the kind of positive PR that’s possible.

After all, many smaller businesses have already taken the necessary steps to create safe ventilation in their buildings. My dentist and physical therapist, and my wife’s massage therapist have all created safe ventilation environments for their places of business. They’re happy to share the details with anyone who asks.

Is it too much to ask meeting venues to do the same?

More resources

Here are some additional resources that you may find useful. Again, please be cautious of any information you find that has not been published or updated in the last few months—it may be outdated.

Thank you

Many thanks to Joan Eisenstodt, Robert Carey, Anne Carey, Barbara McManus, Paul Radde, Dan Cormany, Sarah Diem, and Lauren Siring, who provided information and helpful suggestions and resources as I found my way into the complex topic of venue ventilation for COVID-19!

This April 2021 article includes information I’ve compiled from a variety of current sources. I’ve surely missed some valuable information.  Please help me improve and update what I’ve shared via your comments below. Thank you!

Image attribution: medical.mit.edu