PurpleAir monitors showed that the air around CIT, UCC and Ballinlough were particularly polluted.
The sensors measure the level of particulate matter, or pollution, in the air.
Professor John Wenger of UCC's Centre for Research into Atmospheric Chemistry says these PurpleAir sensors were installed across Cork city as a pilot scheme, in conjunction with Cork City Council.
"The EPA has set up air quality monitoring stations across the country, with some located in Cork city. There is one on UCC, CIT, the South Link Road and in Heatherton Park in Ballinlough," Professor Wenger told The Echo.
"However, these can cost €20,000 to €30,000 per station. The Council and UCC have a pilot project whereby we use PurpleAir sensors, which cost $200 to $300 each, so we can monitor the air quality of a wider area.
"We can use these low-cost sensors to give us indicated measurements. We have deployed a whole network of these, and the results have indicated a huge amount of air pollution."
Professor Wenger says that this air pollution could potentially be caused by people burning solid fuels.
"Buring coal, peat and wood in the home... it might give a warm, cosy fire on a cold night but it is very polluting.
"Cork city has a ban on smoky coal but is it being taken seriously? Peat and wood also contribute to pollution as well.
"You would certainly smell the pollution in the evenings and people with compromised health may be affected."
This morning the CIT sensor had a PM2.5 Air Quality Index of 155, which is high enough for people to potentially experience health effects if they are exposed to this air for 24 hours.
Members of sensitive groups, such as those with asthma or other respiratory illnesses, may experience more serious health effects.
"The sensors measure particulate matter, or PM. These are tiny particles which we can't see. They scatter light and give a smokey atmosphere at night," Professor Wenger explains.
"The smaller the PM, the further it can travel into our organ systems. So, for example, PM2.5 can be breathed into our lungs and go deep into our respiratory system. Some smaller particles can even enter our bloodstream."
"Many studies have shown that air pollution causes a spectrum of health defects, and it affects the brain, organs, our breathing and our heart.
"The World Health Organisation has recognised air pollution as the largest environmental health risk in the world."
Professor Wenger says while the sensors are low-cost, they seem to be working. "We don't know how accurate they are yet, but they seem to be working. They pick up the spikes in pollution in the evening times. They have great potential for further deployment.
"The data is streamed and is freely available, it gives us a good comparison of air pollution across Europe. Last night, Cork city was among, if not the, most polluted place in Europe according to this data."