Air quality has been "extremely" poor in Cork at various times in recent days according to the latest data.
The measurements come as Cork City Council launches a new strategy to combat pollutants around the city that are hampering health and everyday activities.
The Cork Air Quality Twitter account posts automated readings every three hours of real time data taken from the air quality sensor network PurpleAir. It shows the city fluctuated from moderate to very poor and extremely poor over the past few days.
The account advises that when the air is moderate to "enjoy your usual outdoor activities", but that "sensitive groups should consider reducing intense outdoor activities". When air quality is very poor, the account advises restricting intense activity outside.
PurpleAir monitoring showed that over the past week, the average marking for air quality hovered in the poor range.
While air quality in Cork is generally good, according to the Centre for Research into Atmospheric Chemistry (CRAC) based at UCC, there are times when pollution builds in winter to levels that are potentially hazardous.
Cork City Council and CRAC set up the PurpleAir sensor network as a pilot project across the city to monitor particulate matter in the atmosphere in recent years.
Particulate matter is the combination of solid and liquid particles suspended in the air, such as dust, pollen, soot, smoke, and liquid droplets.
The recent drop in air quality comes as Cork City Council announced it is putting its Draft Air Quality Strategy for 2021 to 2026 out for feedback from the public.
The strategy outlines the actions that the local authority will undertake between 2021 and 2026 to reduce the concentrations of air pollutants in the city area, thereby positively impacting on the health and quality of life of residents and visitors, it said.
The strategy will focus on seven aspects, including improving health, air monitoring, travel, electric vehicles and charging infrastructure.
It will also improve regulation and enforcement, concentrate on so-called "green infrastructure", and be led by research and innovation.
Director of operations, David Joyce, said: “The strategy builds on significant work being conducted by Cork City Council to develop a high-quality air monitoring system and to develop initiatives that will significantly lower the levels of pollutants in the air in the city."
Cork City Council is focused on addressing air pollution and continues to enforce the prohibition on the sale of smoky fuel, he added.
The local authority aims for "sustainability, quality of life, and resilience to be at the heart of our city as it grows", according to Mr Joyce.
A survey earlier this week by the Irish Heart Foundation and the Asthma Society of Ireland found that most Irish people remain wholly unaware that fossil fuel burning at home is the main cause of air pollution.
Just over one in 10 believe smoky fuels, including coal, turf and wet wood to heat homes to be the leading source of air pollution - they are actually responsible for the majority of more than 1,200 air pollution deaths in Ireland every year.
“Home fuel burning is having a hugely detrimental impact on the nation’s health – with children, older people and those living with chronic diseases being the worst affected,” said Irish Heart Foundation CEO, Dr Tim Collins.