Ventilation is essential for maintaining an acceptable environment in terms of humidity, heat or cold. A poorly designed ventilation system may cause uneven distribution of the air supply, resulting in cooler environment at the front part of the ventilation line, and warmer at the back. The best solutions are:

• Check that thermostats are working properly.
  
• Rearrange partitions to avoid unwanted air currents or blockage of air flow.
  
• Regular maintenance.
  
• Smoking produces an offensive odour and harmful substances. The best solution is to ban smoking inside offices.

Legionnaires' Disease is caused by the bacteria, Legionella pneumophila and is typically manifested as severe pneumonia often culminated in respiratory failure. Cooling towers, evaporative condensers and hot water systems can become their growth and distribution sites. They flourish well in stagnant and contaminated freshwater sources of ventilation units. The best solutions are:

• Remove all potential nourishing water sources for Legionella, such as stagnant water in drip pans, cooling coils and sumps.
  
• Clean humidifers or ventilation units regularly ( e.g. bimonthly or quarterly)
  
• User air cooled condensers instead of freshwater cooling towers.