# Find the acceptable concentration of CO

• s3a
In summary, the conversation discusses the acceptable concentration of carbon monoxide (CO) in terms of mg/m^3 based on the "National Ambient Air Quality Objectives". The problem at hand is to find the acceptable concentration of CO in ppm at a temperature of -30°C and a pressure of 0.92 atm. The equation PV = nRT is mentioned, but it is noted that this problem involves more arithmetic than chemistry. The main piece of information needed is P/R, and the temperature in this context is not specified. The formula for ppm is given as weight/volume * 10^6, but there is not enough information to accurately calculate this. It is suggested that the given concentration of 35 mg/m^3
s3a

## Homework Statement

Based on the “National Ambient Air Quality Objectives”, the acceptable hourly average concentration of carbon monoxide (CO) is 35 mg/m^3.

Find the acceptable concentration of CO in ppm if the temperature is -30 °C and pressure is 0.92 atm.

Express the concentration as a percent by volume.

PV = nRT (maybe)

## The Attempt at a Solution

Hello, everyone!

So far, I get the following.:
101.325 kPa * V = (35E-3 g / 28.01 g) mol * 8.31 kPa L / (mol K) * (-30 + 273.15) K

V = 0.0249180252056537913 L

Am I on the right track? If so, what do I do next? If not, then what must I do?

Any input would be greatly appreciated!

Last edited:
Write the ppm definition.

Right equation, otherwise not really. We often get questions supposedly of chemistry here which are really problems of arithmetic that students learned years before starting chemistry.

You are given a concentration in mg/m-3 at one T and P. You want to know in the first place the mg /m-3 at another T, P. That is per unit volume - the volume in question, that is the m3 doesn't change. From your equation in 2 what remains the same between the two situations is P/R, can you see? That is the main bit of non-arithmetical knowledge. The other is knowing what is really meant by T in this context.

Work out the new mg/m-3 then what that is in ppm.

Last edited:
epenguin said:
You are given a concentration in mg/m-3 at one T and P.

Not exactly, original T and P are not given.

epenguin said:
Work out the new mg/m-3 then what that is in ppm.

As original statement doesn't contain any additional information, I am ready to assume it is to be understood as "35 mg/m3 at any conditions".

It doesn't say anything about whether is it ppm v/v or w/w, which makes it ambiguous and impossible to answer.

The way I read the question is 35 mg / m^3 at standard conditions is the legislative rule, and that what is sought is the adaption of the legislative rule to the new conditions ( -30 °C and 0.92 atm pressure).

Edit:
As for the ppm formula that you're asking for, according to this link ( https://sciencing.com/calculate-ppm-5194302.html ), it's weight / volume * 10^6.

s3a said:
The way I read the question is 35 mg / m^3 at standard conditions is the legislative rule, and that what is sought is the adaption of the legislative rule to the new conditions ( -30 °C and 0.92 atm pressure).

I am not convinced about the STP part, but you can definitely try this way. Note, that 35 mg of CO at STP means some easy to calculate volume in a well defined volume of air (1 m3). If you change T, P you change it for both gases. Will the ratio of volumes CO/air change? Will the molar ratio of CO/air change? Will the mass ratio of CO/air change? Does it make any sense to make these calculations?

As for the ppm formula that you're asking for, according to this link (...), it's weight / volume * 10^6.

Weight over volume - what units for weight, what units for volume? As long as they are not well defined there is no way to have an unambiguous result.

Compare http://www.chembuddy.com/?left=concentration&right=ppm-ppb-ppt

I still think assuming it is 35 mg per cubic meter of air regardless of T, P is the only way to add sense to the question.

## 1. What is the acceptable concentration of CO?

The acceptable concentration of CO, or carbon monoxide, varies depending on the specific situation. In general, the acceptable level of CO in ambient air is 9 parts per million (ppm) over an 8-hour period, and 35 ppm over a 1-hour period. However, these levels may be lower in certain indoor environments or for individuals with health conditions.

## 2. How is the acceptable concentration of CO determined?

The acceptable concentration of CO is determined through scientific research and risk assessment. This involves studying the effects of CO on human health and the environment, as well as considering factors such as exposure duration and population sensitivity. Government agencies and organizations such as the Environmental Protection Agency (EPA) and the World Health Organization (WHO) set guidelines for acceptable CO levels.

## 3. What are the sources of CO in the environment?

CO can be produced by both natural and human activities. Natural sources include volcanic eruptions and forest fires, while human sources include vehicle exhaust, industrial processes, and burning of fossil fuels. Indoor sources of CO can also include gas stoves, fireplaces, and tobacco smoke.

## 4. What are the health effects of exposure to high levels of CO?

Exposure to high levels of CO can be dangerous and even fatal. CO binds to hemoglobin in the blood, reducing the amount of oxygen that can be transported to the body's tissues. This can lead to symptoms such as headaches, dizziness, nausea, and confusion. Prolonged exposure to high levels of CO can result in unconsciousness, permanent brain damage, and death.

## 5. How can the acceptable concentration of CO be reduced?

The acceptable concentration of CO can be reduced by limiting or eliminating sources of CO, such as reducing vehicle emissions and properly maintaining gas appliances. In indoor environments, installing CO detectors can also help to monitor and alert individuals to high levels of CO. Additionally, proper ventilation and air circulation can help to reduce CO levels in enclosed spaces.

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