diff --git a/caimira/models.py b/caimira/models.py
index 2698ef02..71fbdec3 100644
--- a/caimira/models.py
+++ b/caimira/models.py
@@ -971,10 +971,6 @@ class InfectedPopulation(_PopulationWithVirus):
         ER = (self.virus.viral_load_in_sputum *
               self.activity.exhalation_rate *
               10 ** 6)
-        
-        # if self.people_present(time) == 0:
-        #     return ER
-        # else:
         return ER * self.people_present(time)
 
     @property
diff --git a/caimira/tests/models/test_dynamic_population.py b/caimira/tests/models/test_dynamic_population.py
new file mode 100644
index 00000000..80808524
--- /dev/null
+++ b/caimira/tests/models/test_dynamic_population.py
@@ -0,0 +1,98 @@
+import numpy as np
+import numpy.testing as npt
+import pytest
+
+from caimira import models
+import caimira.dataclass_utils as dc_utils
+
+@pytest.fixture
+def full_exposure_model():
+    return models.ExposureModel(
+        concentration_model=models.ConcentrationModel(
+            room=models.Room(volume=100),
+            ventilation=models.AirChange(
+                active=models.PeriodicInterval(120, 120), air_exch=0.25),
+            infected=models.InfectedPopulation(
+                number=1,
+                presence=models.SpecificInterval(((8, 12), (13, 17), )),
+                mask=models.Mask.types['No mask'],
+                activity=models.Activity.types['Seated'],
+                expiration=models.Expiration.types['Breathing'],
+                virus=models.Virus.types['SARS_CoV_2'],
+                host_immunity=0.
+            ),
+        ),
+        short_range=(),
+        exposed=models.Population(
+            number=10,
+            presence=models.SpecificInterval(((8, 12), (13, 17), )),
+            mask=models.Mask.types['No mask'],
+            activity=models.Activity.types['Seated'],
+            host_immunity=0.
+        ),
+        geographical_data=(),
+    )
+
+
+@pytest.fixture
+def baseline_infected_population_number():
+    return models.InfectedPopulation(
+        number=models.IntPiecewiseContant(
+            (8, 12, 13, 17), (1, 0, 1)),
+        presence=None,
+        mask=models.Mask.types['No mask'],
+        activity=models.Activity.types['Seated'],
+        virus=models.Virus.types['SARS_CoV_2'],
+        expiration=models.Expiration.types['Breathing'],
+        host_immunity=0.,
+    )
+
+
+@pytest.fixture
+def baseline_exposed_population_number():
+    return models.Population(
+        number=models.IntPiecewiseContant(
+            (8, 12, 13, 17), (1, 0, 1)),
+        presence=None,
+        mask=models.Mask.types['No mask'],
+        activity=models.Activity.types['Seated'],
+        host_immunity=0.,
+    )
+
+@pytest.mark.parametrize(
+    "time",
+    [4., 8., 10., 12., 13., 14., 16., 20., 24.],
+)
+def test_population_number(full_exposure_model: models.ExposureModel,
+                           baseline_infected_population_number: models.InfectedPopulation, time: float):
+
+    int_population_number: models.InfectedPopulation = full_exposure_model.concentration_model.infected
+    assert isinstance(int_population_number.number, int)
+    assert isinstance(int_population_number.presence, models.Interval)
+
+    piecewise_population_number: models.InfectedPopulation = baseline_infected_population_number
+    assert isinstance(piecewise_population_number.number,
+                      models.IntPiecewiseContant)
+    assert piecewise_population_number.presence is None
+    
+    assert int_population_number.person_present(time) == piecewise_population_number.person_present(time)
+    assert int_population_number.people_present(time) == piecewise_population_number.people_present(time)
+
+
+@pytest.mark.parametrize(
+    "time",
+    [4., 8., 10., 12., 13., 14., 16., 20., 24.],
+)
+def test_concentration_model_dynamic_population(full_exposure_model: models.ExposureModel,
+                                                baseline_infected_population_number: models.InfectedPopulation,
+                                                baseline_exposed_population_number: models.Population,
+                                                time: float):
+
+    dynamic_model: models.ExposureModel = dc_utils.nested_replace(
+        full_exposure_model,
+        {
+            'concentration_model.infected': baseline_infected_population_number,
+            'exposed': baseline_exposed_population_number,
+        }
+    )
+    assert full_exposure_model.concentration(time) == dynamic_model.concentration(time)