Working with paint all day, every day can easily cause safety and health hazards without adequate precautions.
In older homes, getting air moving through is easier than modern homes, because new houses are 'tightly' built, meaning that ventilation has to be a conscious effort.
Proper ventilation during painting will benefit everyone.
If there is little or no ventilation during application, some people will suffer from health issues such as mild asthma or severe headaches that can last for some time after the actual painting process.
A properly ventilated room will also benefit the quality of the final job. A coat of paint on the walls and ceiling can add up to around 3,000 millilitres of water to the environment, so excessive humidity will impede the paint drying process, whereas adequate ventilation will speed up drying times.
However, in cooler temperatures, the binder in waterborne paints becomes harder, and can be a less hospitable place for surfactants and thickeners. Coupled with poor ventilation, some of those materials can find their way to the surface of the paint, causing a 'smeary' look to the final job.
How to improve ventilation
Improving ventilation therefore has its benefits.
While both air blowing and extraction methods are helpful, research has suggested that air blowing is more efficient as extraction can create pockets of solvent vapour by channelling smooth airflow, whereas air blowing will cause turbulence, dispersing and pockets of solvents.
Apart from the obvious methods of opening windows and doors to create natural air flows, or using ceiling fans and other equipment already available in the area you're painting, investing in specialised fans can pay off for your health and your overall result.