Final answer:
The number of carbon dioxide particles in the atmosphere has been steadily increasing over time due to human activities, especially the burning of fossil fuels since the Industrial Revolution. This rapid increase is much faster than historical fluctuations and is expected to continue if current trends persist.
Step-by-step explanation:
Over time, the concentration of carbon dioxide (CO₂) particles in the atmosphere has been increasing.
In the context of the Douglas bag method, the number of CO₂ particles in the bag would reflect the person's respiratory activity and how much CO₂ they exhale.
When analyzing atmospheric CO₂ over historical periods, based on the ice core samples from Greenland and Antarctica, levels fluctuated between 180-280 ppm, where higher concentrations were associated with warmer interglacial periods.
However, after the onset of the Industrial Revolution, CO₂ levels have risen sharply, exceeding the preindustrial maximum of 300 ppm.
This unprecedented increase in atmospheric CO₂, now measured above 400 ppm, is attributed to the burning of fossil fuels and has occurred over a few centuries, a much faster rate than historical increases which took place over thousands of years.
Scientists predict that CO₂ levels could double before the end of the twenty-first century, largely due to human industrial activity, which could profoundly impact the global climate and ecosystems.