The air in the cotton spinning mills had to be kept hot and humid (65 to 80 degrees) to prevent the thread breaking, so there was no ventilation. On the other hand, weaving sheds were too cold in winter.

I work for twelve hours of the day, and struggle home again.
And when the Factory Act is passed, I'll only work for ten.

Textile workers dreamed of a ten-hour day! From Wikipedia;

The Factory Act of 1847, also known as the Ten Hours Act was a United Kingdom Act of Parliament which restricted the working hours of women and young persons (13-18) in textile mills to 10 hours per day.

The Act of 1847 was the culmination of a campaign lasting almost fifteen years to bring in a 'Ten Hours Bill'; a great Radical cause of the period. Richard Oastler was a prominent and early advocate; the most famous Parliamentarian involved was Lord Ashley who campaigned long and tirelessly on the issue. The eventual success owed much to the mobilisation of support among the mill-workers by organisers such as John Doherty and sympathetic mill-owners such as John Fielden, MP who piloted the Act through the Commons.

The 1847 Act was passed soon after the fall from power of Sir Robert Peel's Conservative government, but the fiercest opponents of all ten-hour bills were the 'free trade' Liberals such as John Bright; the economic doctrines that led them to object to artificial tariff barriers also led them to object to government restricting the terms on which a man might sell his labour, and to extend that objection to women and young peoples.