Every Monday we’ll answer your questions on Covid-19 and health in a feature published online. You can submit a question here.

This week, HuffPost UK reader Jo asked: As Covid-19 spreads through water droplets, how can swimming pools possibly be safe?

Swimming pools are back open in parts of the UK – but some people are sceptical of whether it’s safe to use them. So, what’s the deal?

During the peak of the virus, no cases were reported of Covid-19 spreading in swimming pools or through water. But that doesn’t mean it’s without risks. 

“The risk is not from the SARS-CoV-2 virus surviving and transmitting through the water per se,” says Dr Julian Tang, associate professor in respiratory sciences at the University of Leicester. “The water itself, with the standard bleach or other detergent-based disinfectants, will be effective in killing this virus – it is lipid-enveloped and fragile.”

The risk really occurs above the water, he says, from swimmers chatting at the end of their lanes when they’re within typical conversational distances of 0.5m to 1m. This is because the main route the virus spreads is in droplets propelled into the air when a person speaks, coughs, sings, sneezes or laughs.

Submit a coronavirus health question to HuffPost UK.

Professor Vincenzo Romano Spica is an expert in public health from the University of Rome and one of the lead authors of a paper on swimming pool safety during Covid-19. He tells HuffPost UK he believes it’s safe to go swimming – and he would feel comfortable going swimming himself, in Italy, where he lives.

Chlorinated pools are considered safest, as they’re maintained and regularly disinfected, which can help to deactivate the virus. The World Health Organisation (WHO) suggests “swimming in a well-maintained, properly chlorinated pool is safe”.

That said, there are some other key risk factors to think about first. 

Are cases in your area rising?

A key thing to consider before reaching for your goggles is how many people in your local area (or the area where you plan to swim) have Covid-19.

In places where cases are rising and lockdowns are being enforced, swimming pools would be more risky to visit than areas where there are a handful of cases. You can find out how many cases are in your local area.

In Italy and other European countries where incidence is low, Prof Romano Spica believes it’s safe to swim. But in parts of the USA, India and other areas where outbreaks are emerging or present, it’s a no-go.

How busy is the pool?

WHO recommends people avoid crowded swimming pools and keep at least one metre away from people who sneeze or cough. Among epidemiologists, two metres is still considered to be the optimum distance. 

Crowding and personal distancing are key factors, more than water, says Prof Romano Spica, so the emptier the pool is, the better. Under UK government guidance, leisure facilities should ensure an appropriate number of people are allowed in the swimming pool at any one time.

How close are you to other swimmers?

“It’s possible that exposure may occur in adjacent lanes if swimmers are too close together,” says Dr Tang. He offers the example of an infected swimmer coming to the surface and exhaling strongly before taking their next breath, just as another swimmer comes the other way and passes them, inhaling strongly before their next stroke. There would be potential to breathe in the virus.

“But the frequency of this type of encounter would be rare,” he points out, “and if the lanes are wider and each swimmer stays within the middle of their lane, this reduces the transmission risk further as this is effectively a form of social distancing.”

What is the pool used for?

Find out what the pool is used for before you decide to visit. If, for instance, the pool is used for exercise and sport, there’s likely to be greater physical distancing (as there’ll hopefully be lanes in place) and not as many people using it. It’s also less likely there’ll be bodily fluids knocking around than, say, a pool on holiday. 

But on the other hand, pools that form part of residential complexes or are aimed at allowing people of different ages to sunbathe, refresh, play and socialise, can often result in overcrowded conditions, which would pose more of a risk. There’s also more of a chance that people will be shouting and laughing – both of which can spread the virus to people nearby.

Indoor vs outdoor pools – which is best?

HuffPost UK reader Brian asked whether it’s safe to go swimming in indoor pools. In the UK it’s deemed safe to swim in indoor pools, which opened at the end of July. But outdoor pools are considered safer.

“Outdoor pools have the advantage of sunlight and wind to destroy the virus and/or blow it away before it reaches the other person,” says Dr Tang. 

Dr Tang adds that swimming indoors (or outdoors) wouldn’t be high risk if the lanes are wider, with only one swimmer per lane; and if swimmers don’t talk to each other at the end of their lanes, or before entering or after leaving the pool. He concludes: “Being antisocial is being safe!”

If you’re worried about transmission in an indoor setting, arrive in your swimming gear, so you don’t have to use changing rooms, and take your own equipment/aids. This is advised by Swim England. Use hand sanitiser before entering and when leaving the pool, too. 

To protect others, in the event that you might be asymptomatic, you could consider wearing a face cover when you’re not using the pool.

If you feel nervous about returning, phone your leisure centre beforehand to see what practices they have in place to keep people safe. You could also ask what the least busy times are to visit, for peace of mind. 

The text above is a summary, you can read full article here.