In the middle of a pandemic, how dangerous is dropping your mask and downing a few beers in a bar? Are you risking a side of Covid with your cocktail?
A good indoor CO2 reading is anything under 800 parts per million. Photo: No metadata
Armed with a carbon dioxide monitor, RNZ went on a Friday night pub crawl to investigate the air quality of central Auckland bars.
Although there's no way of seeing how many virus particles are circulating in a space, measuring carbon dioxide (CO2) levels is one way to get a fair idea.
With every breath, we take in air and exhale CO2, but a certain proportion of the air we inhale is laden with other people's outbreaths. With that comes a plethora of virus particles.
Read more from this series:
- Whose breath are you breathing?
- Cost concerns scupper fresh air plans for Auckland buses
- Lack of classroom CO2 monitors may increase Covid-19 risk
- Why your gym's air might not be fit to breathe
University of Auckland aerosol chemist Dr Joel Rindelaub says carbon dioxide levels have become a proxy for Covid-19 risk.
"Every time you talk, breathe, or cough, you're emitting tiny little particles in the air that are just going to float around, and that other people can breathe in. So you're breathing in someone else's respiratory particles. Once they get in your body, they can then infect you."
Bars are likely to increase risk because talking expels "thousands more" particles than breathing, says Rindelaub.
If there's a person infected with Covid-19 in the same space, then you risk catching it too.
A good indoor CO2 reading is anything under 800 parts per million. Levels between 800 and 1000ppm show the environment is risky, and anything over 1000ppm is high risk.
Rindelaub says levels above 2000ppm are a "red flag".
So on a typical Friday night out in Auckland, what is the air quality like inside bars?
It's early when we visit the first bar of the night, which is medium-sized and isn't very full yet. Windows are shut, but the door is open.
After enjoying our first drink there, the next stop is a small bar. The only free table is toward the back of the bar, away from the open front door. There are 18 people inside, around the same as the previous bar, but this is a smaller space.
The third bar is bigger, with 25 people inside, but groups are well spaced out. The front door is open and letting in plenty of air. This is the best reading taken all evening, and falls into the safe category of under 800ppm of CO2.
This is another big bar, which isn't crowded and has high ceilings. It's the first bar of the night with closed doors. It's just above what's considered the safe indoor level.
There are 24 people in this medium-sized bar. There's air conditioning going here and the door is open, but only to an indoor space where more people are sitting and talking
Now things are getting rowdy. There's a band belting out cover tunes and people are singing and dancing. This is the first place where we've hit "red flag" levels of over 2000ppm of carbon dioxide. It's a large bar, but it's the busiest yet, with about 150 people inside.
The next stop is also at "red flag" levels but conditions inside are completely different to the previous bar. It's small, there are only 22 people inside and the music is quiet, so you don't need to shout to be heard. The doors are closed.
This bar is huge, with plenty of people - about 100 - in well spaced-out groups. There are scattered outbreaks of dancing. Doors are open, but the spot in the back where this reading was taken shows levels are in the high-risk range.
The second-to-last stop of the evening is a small bar with live music and dancing. The front doors are open, but with about 50 people inside it doesn't seem to be helping much.
We arrive at the last bar of the night just as a band finishes playing, with people pouring out of the venue. About 80 to 100 people are inside. At 1880 it's still high risk, but it doesn't reach the red flag level.
Managing risk
Of the 10 bars visited, only one had a CO2 level below 800ppm, considered a safe level to reduce the risk of Covid-19 transmission. Three had levels which Rindelaub describes as a "red flag".
No venues had their own CO2 monitor on display. Rindelaub says this means patrons have no way of knowing their risk.
As a "science geek", he would love indoor establishments to have visible CO2 monitors so staff and patrons can see the risk and know when to open doors and windows.
RNZ asked Hospitality New Zealand if it encourages the use of CO2 monitors inside bars, but it said it was too busy to answer questions.
Raise The Bar union leader Chloe Ann-King thinks the industry doesn't take health and safety seriously enough. The union represents hospitality workers, including bar staff, who are on the front line, night after night.
"Hospo is a high-risk industry," she says. "The music's loud, so when you're at the bar, customers are having to lean in and yell at you their order. You can feel their spit on your face, they're drunk."
She thinks CO2 monitors inside hospitality venues would be a good idea.
"If you can't measure the air you don't know when you need to open a door or turn on the aircon or put on a fan at the very least.
"Arguably that should be a requirement under health and safety [regulations]."
She's heard of workers catching Covid-19 and getting reinfected within three months, and says hospitality staff often battle on through sickness and injury. Part of this is due to an entrenched culture, she says, but the fact that workers are not eligible for sick leave until they've been at a job for six months is another contributing factor.
"I really hate to think of the consequences for a lot of hospo workers who have Long Covid and ongoing health problems because of being reinfected."