Parts per Million (ppm): Study with Video Lessons, Practice Problems & Examples

Parts per million (PPM) and parts per billion (PPB) are units used to express extremely dilute solution concentrations. PPM represents grams or milliliters of solute per 1,000,000 parts, with 1 PPM equating to 1 milligram per liter. The formula for PPM is: $\frac{\mathrm{grams}of\mathrm{solute}}{\mathrm{grams}of\mathrm{solution}}10^6$. PPB, on the other hand, indicates grams or milliliters per 1,000,000,000 parts, with 1 PPB equal to 1 microgram per liter, calculated similarly using $\frac{\mathrm{grams}of\mathrm{solute}}{\mathrm{grams}of\mathrm{solution}}10^9$.

Parts per Million (ppm) Concept 1

Here we're going to say that extremely dilute solution concentrations are expressed in parts per million, abbreviated as PPM, or parts per billion, abbreviated as PPB. Now we're going to say here units can either be in mass or volume when it comes to PPM or PPB. Now let's take a look at parts per million. We're going to say this represents the number of parts either in grams or milliliters per 1,000,000 parts. And remember, 1,000,000 is 106. In an aqueous solution, a helpful thing to help you with parts per million is that 1 parts per million is equivalent to 1 milligram per 1 liter. So here, if we take a look at parts per million, we can look at it in either our form of mass or in a form of volume. And if we're looking at parts per million in terms of mass, we're going to say it equals grams of solute divided by grams of solution times 106. And if we're looking at parts per million in terms of volume, then it becomes milliliters of solute divided by milliliters of solution times 106. So this setup should be kind of reminiscent of mass percent where it'd be grams over grams times 100%. Now, instead of doing 100%, we're now dealing with 106 because we're dealing with 1,000,000 parts, 1,000,000 parts. Alright. So just keep in mind, we deal with PPM and later on PPB when discussing very extremely dilutive concentrations.

Parts per Million (ppm) Example 1

What is the concentration in parts per million of DDT, a non-biodegradable pesticide in 2 milligrams in 1 kilogram of needlefish tissue? Alright. So we want parts per million. So that's going to equal the grams of our solute divided by grams of solution times 10 to the 6. We have an issue though. These units are not in grams. One's in grams, one's in milligrams, one's in kilograms. Convert them both to grams first. So we have 2 milligrams. And remember, 1 milligram, 1 milli is 10-3. So that's 2.0×10-3g. And then remember, 1 kilogram is equivalent to 1,000 grams. So we take that and plug it in. So we have 2.0×10-3g divided by 1000g times 106. When we do that we get back 2.0 PPM. So that will be our part per million of DDT for this particular example question.

Parts per Million (ppm) Concept 2

PPB, otherwise known as parts per billion, represents the number of parts either in grams or milliliters per 1,000,000,000 parts. And remember, 1,000,000,000 is 109. Now when in aqueous solutions, just remember that we can make the connection that 1 ppb equals 1 microgram per 1 liter. Now, when dealing with parts per billion in terms of mass, we're going to say it's equal to grams of solute divided by grams of solution times 109. And when looking at parts per billion in terms of volume, it then becomes milliliters of solute divided by milliliters of solution times 109. So just keep in mind, when dealing with parts per billion in an aqueous solution, there's this connection. And also the difference between parts per billion when dealing with mass and when dealing with volume.

Parts per Million (ppm) Example 2

A 2.4 liter sample of an aqueous solution contains 0.012 milliliters of ammonia. What is the concentration of ammonia in the solution expressed as parts per billion?

Alright. Since we're dealing with volume here, that must mean we are dealing with parts per billion in terms of volume. So, we'd say here parts per billion would equal the milliliters of our solute divided by milliliters of our solution, which in this case is our sample, times 10⁹.

Here we plug in 0.012 milliliters of our ammonia, which is our solute, divided by now we need to convert liters into milliliters. And remember that for every 1 liter, it's 10³ milliliters. So here, that comes out to 2,400 milliliters, which is what we're going to place over here. And then times 10⁹. When we do that, that's going to give me, as an answer, 5,000 parts per billion.

And out of the choices shown, option B will be the correct answer. So, B, 5000 parts per 1,000,000,000, will be the correct concentration of NH₃ expressed in parts per billion.

A 5.12 L sample of solution contains 0.230 g of potassium sulfate, K₂SO₄. Determine the concentration of K₂SO₄ in ppm if the density of the solution is 1.30 g/mL.

• A. 34.6 ppm
• B. 28.9 ppm
• C. 22.3 ppm
• D. 43.6 ppm

Calculate the concentration in parts per billion of the following aqueous solution:0.91 mg of caffeine in a total volume of 131 mL.

• A. 0.14 ppb
• B. 0.0069 ppb
• C. 140 ppb
• D. 6900 ppb

Glucose makes up about 0.102% by mass of human blood. Calculate this concentration in ppm.

• A. 102 ppm
• B. 0.102 ppm
• C. 0.00102 ppm
• D. 1020 ppm

The average human body contains about 5,000 grams of blood. What mass of arsenic is present in the body if the amount in blood is 0.86 ppb?

• A. 5.8 x 10¹² g
• B. 4.3 x 10¹² g
• C. 4.3 x 10^-6 g
• D. 5.8 x 10^-6 g

A water sample contains the pollutant chlorobenzene with a concentration of 16 ppm (by volume). What volume of this water contains 5.01×10² mL of chlorobenzene?

• A. 3.1 x 10⁷ mL
• B. 3.2 x 10⁴ mL
• C. 1.6 x 10⁶ mL
• D. 8.0 x 10¹⁰ mL

Here’s what students ask on this topic:

What is the definition of parts per million (PPM) and how is it calculated?

Parts per million (PPM) is a unit used to express extremely dilute concentrations of a substance in a solution. It represents the number of parts of solute (either in grams or milliliters) per 1,000,000 parts of the solution. The formula for calculating PPM in terms of mass is:

$\frac{\mathrm{grams} \mathrm{of} \mathrm{solute}}{\mathrm{grams} \mathrm{of} \mathrm{solution}} \times {10}^6$

In terms of volume, it is:

$\frac{\mathrm{milliliters} \mathrm{of} \mathrm{solute}}{\mathrm{milliliters} \mathrm{of} \mathrm{solution}} \times {10}^6$

In aqueous solutions, 1 PPM is equivalent to 1 milligram per liter.

How do you convert parts per million (PPM) to milligrams per liter (mg/L)?

In aqueous solutions, converting parts per million (PPM) to milligrams per liter (mg/L) is straightforward because 1 PPM is directly equivalent to 1 mg/L. This is due to the fact that 1 liter of water weighs 1,000 grams, and thus 1 milligram of solute in 1 liter of water is 1 part per million. Therefore, the conversion is:

$\text{1 PPM = 1 mg/L}$

What is the difference between parts per million (PPM) and parts per billion (PPB)?

Parts per million (PPM) and parts per billion (PPB) are both units used to express very dilute concentrations, but they differ in scale. PPM represents the number of parts of solute per 1,000,000 parts of solution, while PPB represents the number of parts of solute per 1,000,000,000 parts of solution. In aqueous solutions, 1 PPM is equivalent to 1 milligram per liter (mg/L), and 1 PPB is equivalent to 1 microgram per liter (μg/L). The formulas are:

For PPM:

$\frac{\mathrm{grams} \mathrm{of} \mathrm{solute}}{\mathrm{grams} \mathrm{of} \mathrm{solution}} \times {10}^6$

For PPB:

$\frac{\mathrm{grams} \mathrm{of} \mathrm{solute}}{\mathrm{grams} \mathrm{of} \mathrm{solution}} \times {10}^9$

How do you calculate parts per billion (PPB) in a solution?

Parts per billion (PPB) is used to express extremely dilute concentrations of a substance in a solution. It represents the number of parts of solute (either in grams or milliliters) per 1,000,000,000 parts of the solution. The formula for calculating PPB in terms of mass is:

$\frac{\mathrm{grams} \mathrm{of} \mathrm{solute}}{\mathrm{grams} \mathrm{of} \mathrm{solution}} \times {10}^9$

In terms of volume, it is:

$\frac{\mathrm{milliliters} \mathrm{of} \mathrm{solute}}{\mathrm{milliliters} \mathrm{of} \mathrm{solution}} \times {10}^9$

In aqueous solutions, 1 PPB is equivalent to 1 microgram per liter (μg/L).

What are some practical applications of parts per million (PPM) and parts per billion (PPB) measurements?

Parts per million (PPM) and parts per billion (PPB) measurements are crucial in various fields for monitoring and controlling extremely dilute concentrations. In environmental science, PPM and PPB are used to measure pollutant levels in air, water, and soil, ensuring they meet safety standards. In chemistry and biology, these units help quantify trace elements and contaminants in samples. In the food industry, PPM and PPB are used to monitor additives and contaminants to ensure food safety. Additionally, in pharmaceuticals, these measurements ensure the purity and concentration of drugs. Overall, PPM and PPB are essential for maintaining safety, quality, and compliance across multiple industries.