Catching COVID-19 on a train is just as likely wherever you sit or stand, according to new research.
There is no 'safe spot' that reduces risk as airborne diseases spread along the length of a carriage.
In the absence of effective ventilation systems, commuters have nowhere to escape or hide, scientists say.
The study found air flow is slowest in the center - yet this has no affect on an individual's vulnerability.
First author Rick de Kreij, of Cambridge University, explained: "If an infectious person is in the middle of the carriage, then they’re more likely to infect people than if they were standing at the end.
"However, in a real scenario, people don't know where an infectious person is, so infection risk is constant no matter where you are in the carriage."
The findings in the journal Indoor Air are based on computer simulations and controlled experiments in a real train carriage.
They also showed masks are more effective than social distancing at preventing transmission - especially in trains that are not ventilated with fresh air.
The results also demonstrate how challenging it is for individuals to calculate absolute risk.
Mr de Kreij called on train operators to improve ventilation systems to help keep passengers safe from respiratory infections - including flu.
He said: "In order to improve ventilation systems it's important to understand how airborne diseases spread in certain scenarios, but most models are very basic and can’t make good predictions.
"Most simple models assume the air is fully mixed, but that’s not how it works in real life.
"There are many different factors which can affect the risk of transmission in a train - whether the people in the train are vaccinated, whether they're wearing masks, how crowded it is, and so on.
"Any of these factors can change the risk level, which is why we look at relative risk, not absolute risk - it's a toolbox that we hope will give people an idea of the types of risk for an airborne disease on public transport."
His team developed a one-dimensional model which illustrates how an airborne disease such as COVID-19 can spread.
It's based on a single train carriage with closing doors at either end and can be adapted to fit different types of transport - such as planes or buses.
The motion is linear - to the left or right only. It considers the essential physics for transporting airborne contaminants while being much cheaper than 3D models.
It was validated using measurements of controlled carbon dioxide tests conducted in a full-scale railway carriage.
CO2 levels from participants were measured at several points. The evolution of the gas showed a high degree of overlap with the modeled concentrations.
Many commuter trains in the UK have been manufactured to be as cheap as possible when it comes to comfort - getting the maximum number of seats per carriage.
In addition, instead of pulling fresh air in from outside - which has to be heated or cooled at more cost - they recirculate it.
So, if it’s impossible for passengers to know whether they're sharing a train carriage with an infectious person, what should they do to keep themselves safe?
Mr de Kreij said: "Space out as much as you reasonably can - physical distancing isn't the most effective method but it does work when capacity levels are below 50 percent.
"And wear a high-quality mask which will not only protect you from COVID-19 — but other common respiratory illnesses."
The researchers are now looking to extend their 1D model into a slightly more complex, yet still energy-efficient, zonal version where cross-sectional flow is characterized in different zones.
It could also be extended to include thermal stratification which would offer a better understanding of the spread of an airborne contaminant.
Stories and infographics by ‘Talker Research’ are available to download & ready to use. Stories and videos by ‘Talker News’ are managed by SWNS. To license content for editorial or commercial use and to see the full scope of SWNS content, please email [email protected] or submit an inquiry via our contact form.
We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of ALL the cookies. However, you may visit "Cookie Settings" to provide a controlled consent.
This website uses cookies to improve your experience while you navigate through the website. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. We also use third-party cookies that help us analyze and understand how you use this website. These cookies will be stored in your browser only with your consent. You also have the option to opt-out of these cookies. But opting out of some of these cookies may affect your browsing experience.
Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously.
Cookie
Duration
Description
__hssc
1 hour
HubSpot sets this cookie to keep track of sessions and to determine if HubSpot should increment the session number and timestamps in the __hstc cookie.
__hssrc
session
This cookie is set by Hubspot whenever it changes the session cookie. The __hssrc cookie set to 1 indicates that the user has restarted the browser, and if the cookie does not exist, it is assumed to be a new session.
_GRECAPTCHA
5 months 27 days
Google Recaptcha service sets this cookie to identify bots to protect the website against malicious spam attacks.
cookielawinfo-checkbox-advertisement
1 year
Set by the GDPR Cookie Consent plugin, this cookie records the user consent for the cookies in the "Advertisement" category.
cookielawinfo-checkbox-analytics
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checkbox-functional
11 months
The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checkbox-necessary
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-others
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-performance
11 months
This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
CookieLawInfoConsent
1 year
CookieYes sets this cookie to record the default button state of the corresponding category and the status of CCPA. It works only in coordination with the primary cookie.
ts
1 year 1 month 1 day
PayPal sets this cookie to enable secure transactions through PayPal.
usprivacy
1 year 1 month
This is a consent cookie set by Dailymotion to store the CCPA consent string (mandatory information about an end-user being or not being a California consumer and exercising or not exercising its statutory right).
viewed_cookie_policy
11 months
The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.
Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features.
Cookie
Duration
Description
__cf_bm
30 minutes
Cloudflare set the cookie to support Cloudflare Bot Management.
li_gc
5 months 27 days
Linkedin set this cookie for storing visitor's consent regarding using cookies for non-essential purposes.
lidc
1 day
LinkedIn sets the lidc cookie to facilitate data center selection.
UserMatchHistory
1 month
LinkedIn sets this cookie for LinkedIn Ads ID syncing.
v1st
1 year 1 month 1 day
The v1st cookie is set by TripAdvisor to collect details about how visitors use the website, by displaying user reviews, awards and information received on the TripAdvisor community.
Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors.
Cookie
Duration
Description
_gat
1 minute
Google Universal Analytics sets this cookie to restrain request rate and thus limit data collection on high-traffic sites.
_p_hfp_client_id
less than a minute
Elfsight sets this cookie to implement social platforms on the website and enables the social platforms to track the users by assigning them a specific ID.
dmvk
session
The dmvk cookie is set by Dailymotion to record data of visitor behaviour on the website.
SRM_B
1 year 24 days
Used by Microsoft Advertising as a unique ID for visitors.
Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc.
Cookie
Duration
Description
__hstc
6 months
Hubspot set this main cookie for tracking visitors. It contains the domain, initial timestamp (first visit), last timestamp (last visit), current timestamp (this visit), and session number (increments for each subsequent session).
_clck
1 year
Microsoft Clarity sets this cookie to retain the browser's Clarity User ID and settings exclusive to that website. This guarantees that actions taken during subsequent visits to the same website will be linked to the same user ID.
_clsk
1 day
Microsoft Clarity sets this cookie to store and consolidate a user's pageviews into a single session recording.
_fbp
3 months
Facebook sets this cookie to display advertisements when either on Facebook or on a digital platform powered by Facebook advertising after visiting the website.
_ga
1 year 1 month 4 days
Google Analytics sets this cookie to calculate visitor, session and campaign data and track site usage for the site's analytics report. The cookie stores information anonymously and assigns a randomly generated number to recognise unique visitors.
_ga_*
1 year 1 month 4 days
Google Analytics sets this cookie to store and count page views.
_gat_gtag_UA_*
1 minute
Google Analytics sets this cookie to store a unique user ID.
_gcl_au
3 months
Google Tag Manager sets the cookie to experiment advertisement efficiency of websites using their services.
_gid
1 day
Google Analytics sets this cookie to store information on how visitors use a website while also creating an analytics report of the website's performance. Some of the collected data includes the number of visitors, their source, and the pages they visit anonymously.
AnalyticsSyncHistory
1 month
Linkedin set this cookie to store information about the time a sync took place with the lms_analytics cookie.
CLID
1 year
Microsoft Clarity set this cookie to store information about how visitors interact with the website. The cookie helps to provide an analysis report. The data collection includes the number of visitors, where they visit the website, and the pages visited.
CONSENT
2 years
YouTube sets this cookie via embedded YouTube videos and registers anonymous statistical data.
hubspotutk
6 months
HubSpot sets this cookie to keep track of the visitors to the website. This cookie is passed to HubSpot on form submission and used when deduplicating contacts.
ln_or
1 day
Linkedin sets this cookie to registers statistical data on users' behaviour on the website for internal analytics.
MR
7 days
This cookie, set by Bing, is used to collect user information for analytics purposes.
SM
session
Microsoft Clarity cookie set this cookie for synchronizing the MUID across Microsoft domains.
Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. These cookies track visitors across websites and collect information to provide customized ads.
Cookie
Duration
Description
ANONCHK
10 minutes
The ANONCHK cookie, set by Bing, is used to store a user's session ID and verify ads' clicks on the Bing search engine. The cookie helps in reporting and personalization as well.
bcookie
1 year
LinkedIn sets this cookie from LinkedIn share buttons and ad tags to recognize browser IDs.
bscookie
1 year
LinkedIn sets this cookie to store performed actions on the website.
fr
3 months
Facebook sets this cookie to show relevant advertisements by tracking user behaviour across the web, on sites with Facebook pixel or Facebook social plugin.
IDE
1 year 24 days 1 minute
Google DoubleClick IDE cookies store information about how the user uses the website to present them with relevant ads according to the user profile.
li_sugr
3 months
LinkedIn sets this cookie to collect user behaviour data to optimise the website and make advertisements on the website more relevant.
muc_ads
1 year 1 month 4 days
Twitter sets this cookie to collect user behaviour and interaction data to optimize the website.
MUID
1 year 24 days
Bing sets this cookie to recognise unique web browsers visiting Microsoft sites. This cookie is used for advertising, site analytics, and other operations.
personalization_id
1 year 1 month 4 days
Twitter sets this cookie to integrate and share features for social media and also store information about how the user uses the website, for tracking and targeting.
test_cookie
15 minutes
doubleclick.net sets this cookie to determine if the user's browser supports cookies.
ttwid
1 year
Tiktok sets this cookie to keep track of user authentication and session information.
VISITOR_INFO1_LIVE
5 months 27 days
YouTube sets this cookie to measure bandwidth, determining whether the user gets the new or old player interface.
VISITOR_PRIVACY_METADATA
6 months
YouTube sets this cookie to store the user's cookie consent state for the current domain.
YSC
session
Youtube sets this cookie to track the views of embedded videos on Youtube pages.
yt-remote-connected-devices
never
YouTube sets this cookie to store the user's video preferences using embedded YouTube videos.
yt-remote-device-id
never
YouTube sets this cookie to store the user's video preferences using embedded YouTube videos.
yt.innertube::nextId
never
YouTube sets this cookie to register a unique ID to store data on what videos from YouTube the user has seen.
yt.innertube::requests
never
YouTube sets this cookie to register a unique ID to store data on what videos from YouTube the user has seen.