**Maximum Allowable Concentration of CO2 in Air**

The maximum allowable concentration of CO2 in air for safe working is 5000 ppm (parts per million). This means that the level of CO2 in the air should not exceed 5000 ppm to ensure the safety of workers.

**Explanation:**

Carbon dioxide (CO2) is a colorless and odorless gas that is naturally present in the atmosphere. It is produced through various natural and anthropogenic processes, including respiration, combustion of fossil fuels, and industrial activities. While CO2 is a natural component of the atmosphere, elevated levels can have adverse effects on human health and safety.

When the concentration of CO2 in the air increases, it can lead to a decrease in the oxygen concentration. This can result in a condition known as oxygen deprivation or asphyxiation, which can be harmful and potentially fatal. Therefore, it is crucial to establish a maximum allowable concentration of CO2 in the air to ensure the safety of workers in various industries.

**Occupational Safety Standards:**

Occupational safety standards and guidelines have been established by regulatory bodies to protect workers from the harmful effects of various gases, including CO2. These standards provide maximum allowable concentration limits for CO2 in the workplace to maintain a safe working environment.

**Maximum Allowable Concentration:**

The maximum allowable concentration of CO2 in the air for safe working is set at 5000 ppm. This means that in any given workplace, the concentration of CO2 should not exceed 5000 ppm to ensure the safety of workers.

Exceeding this limit can result in symptoms such as headaches, dizziness, shortness of breath, and confusion. Prolonged exposure to high levels of CO2 can lead to more severe health effects, including respiratory problems, cardiovascular issues, and even death.

Therefore, it is essential for employers to monitor and control the levels of CO2 in the workplace to ensure the health and safety of their employees. This can be achieved through proper ventilation systems, regular air quality testing, and compliance with occupational safety standards.

In summary, the maximum allowable concentration of CO2 in the air for safe working is 5000 ppm. It is crucial to adhere to this limit to prevent adverse health effects and maintain a safe working environment.