diff --git a/docs/issues.md b/docs/issues.md
index 13abc96..7b2aa12 100644
--- a/docs/issues.md
+++ b/docs/issues.md
@@ -17,9 +17,9 @@ El usuario reporta desbordamiento ("ovf") al utilizar valores muy altos en `setA
 Se detectó que la resistencia del sensor se calculaba con `_VOLT_RESOLUTION` en lugar del voltaje de alimentación real. Se añadieron los métodos `setVCC` y `getVCC` y se modificaron las ecuaciones para usar `VCC`. Esta corrección se refleja en la versión 3.0.1 de la biblioteca.
 
 ### #70 Parameters to model temperature and humidity dependence
-**Estado:** abierto
+**Estado:** resuelto en la rama `work`
 
-Los usuarios solicitan factores de corrección para temperatura y humedad aplicables a otros sensores (MQ-4 y MQ-8) además del MQ-135. Aún no se han añadido estos parámetros. Se anima a la comunidad a contribuir con implementaciones y ejemplos.
+Se añadieron variables opcionales de "correction factor" en todos los ejemplos y se extendieron las funciones `calibrate` y `readSensorR0Rs` para aceptar este parámetro opcional. Así, el usuario puede ajustar las lecturas en función de temperatura y humedad cuando el datasheet lo permita. Los coeficientes deben consultarse para cada sensor.
 
 ### #67 Sensor won't finish the Calibration process if done in clean air
 **Estado:** abierto
diff --git a/examples/Alcoholimeter/Alcoholimeter.ino b/examples/Alcoholimeter/Alcoholimeter.ino
index 6bca692..73c1b50 100644
--- a/examples/Alcoholimeter/Alcoholimeter.ino
+++ b/examples/Alcoholimeter/Alcoholimeter.ino
@@ -87,7 +87,8 @@ void setup() {
 
 void loop() {
   MQ3.update(); // Update data, the arduino will read the voltage from the analog pin
-  alcoholPPM = MQ3.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  alcoholPPM = MQ3.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   Serial.print("Alcohol now (PPM): ");
   Serial.println(alcoholPPM);
   delay(500); //Sampling frequency
diff --git a/examples/ESP32/ESP32.ino b/examples/ESP32/ESP32.ino
index cf7c862..7e16d47 100644
--- a/examples/ESP32/ESP32.ino
+++ b/examples/ESP32/ESP32.ino
@@ -87,7 +87,8 @@ void setup() {
 
 void loop() {
   MQ3.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ3.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ3.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ3.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/ESP32/ESP32_WROOM_32D/ESP32_WROOM_32D.ino b/examples/ESP32/ESP32_WROOM_32D/ESP32_WROOM_32D.ino
index 9784e9d..8430341 100644
--- a/examples/ESP32/ESP32_WROOM_32D/ESP32_WROOM_32D.ino
+++ b/examples/ESP32/ESP32_WROOM_32D/ESP32_WROOM_32D.ino
@@ -129,7 +129,8 @@ void loop()
 {
   MQ2.update(); // Update data, the arduino will read the voltage from the analog pin
   //MQ2.serialDebug(); // Will print the table on the serial port
-  Serial.print(MQ2.readSensor()); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  Serial.print(MQ2.readSensor(false, correctionFactor)); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   Serial.println(" PPM");
   delay(500); //Sampling frequency
 }
diff --git a/examples/ESP8266/ESP8266.ino b/examples/ESP8266/ESP8266.ino
index 99c1fb2..4eb03c7 100644
--- a/examples/ESP8266/ESP8266.ino
+++ b/examples/ESP8266/ESP8266.ino
@@ -87,7 +87,8 @@ void setup() {
 
 void loop() {
   MQ3.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ3.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ3.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ3.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/LinearVsExponential/LinearVsExponential.ino b/examples/LinearVsExponential/LinearVsExponential.ino
index 9634e1a..75474d4 100644
--- a/examples/LinearVsExponential/LinearVsExponential.ino
+++ b/examples/LinearVsExponential/LinearVsExponential.ino
@@ -81,17 +81,18 @@ void setup() {
 
 void loop() {
   MQ4.update(); // Update data, the arduino will read the voltage from the analog pin
+  float correctionFactor = 0; // Optional environmental correction
   
   //https://jayconsystems.com/blog/understanding-a-gas-sensor 
   //Set math model to calculate the PPM concentration and the value of constants
   MQ4.setRegressionMethod(0); //_PPM =  pow(10, (log10(ratio)-b)/a)
   MQ4.setA(-0.318); MQ4.setB(1.133); // A -> Slope, B -> Intersect with X - Axis
-  float LPG1 = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float LPG1 = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   
   //Set math model to calculate the PPM concentration and the value of constants
   MQ4.setRegressionMethod(1); //_PPM =  a*ratio^b
   MQ4.setA(1012.7); MQ4.setB(-2.786); // Configure the equation to to calculate CH4 concentration
-  float LPG2 = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float LPG2 = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   //  exposure to 2000 ppm of LPG gas is immediately dangerous to life and health. In this section
   if(LPG1>=2000 || LPG2>=2000) Serial.println("Warning - Very high concentrations detected!");
diff --git a/examples/MQ-135-ALL/MQ-135-ALL.ino b/examples/MQ-135-ALL/MQ-135-ALL.ino
index 8220570..3ffae99 100644
--- a/examples/MQ-135-ALL/MQ-135-ALL.ino
+++ b/examples/MQ-135-ALL/MQ-135-ALL.ino
@@ -78,24 +78,25 @@ void setup() {
 
 void loop() {
   MQ135.update(); // Update data, the arduino will read the voltage from the analog pin
+  float correctionFactor = 0; // Optional environmental correction
 
   MQ135.setA(605.18); MQ135.setB(-3.937); // Configure the equation to calculate CO concentration value
-  float CO = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CO = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(77.255); MQ135.setB(-3.18); //Configure the equation to calculate Alcohol concentration value
-  float Alcohol = MQ135.readSensor(); // SSensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Alcohol = MQ135.readSensor(false, correctionFactor); // SSensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(110.47); MQ135.setB(-2.862); // Configure the equation to calculate CO2 concentration value
-  float CO2 = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CO2 = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(44.947); MQ135.setB(-3.445); // Configure the equation to calculate Toluen concentration value
-  float Toluen = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Toluen = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   
   MQ135.setA(102.2 ); MQ135.setB(-2.473); // Configure the equation to calculate NH4 concentration value
-  float NH4 = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float NH4 = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(34.668); MQ135.setB(-3.369); // Configure the equation to calculate Aceton concentration value
-  float Aceton = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Aceton = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   Serial.print("|   "); Serial.print(CO); 
   Serial.print("   |   "); Serial.print(Alcohol);
   // Note: 400 Offset for CO2 source: https://github.com/miguel5612/MQSensorsLib/issues/29
diff --git a/examples/MQ-135/MQ-135.ino b/examples/MQ-135/MQ-135.ino
index dfbc5e4..27c61b4 100644
--- a/examples/MQ-135/MQ-135.ino
+++ b/examples/MQ-135/MQ-135.ino
@@ -89,7 +89,8 @@ void setup() {
 
 void loop() {
   MQ135.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ135.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-136/MQ-136.ino b/examples/MQ-136/MQ-136.ino
index 9c68f01..9b422ce 100644
--- a/examples/MQ-136/MQ-136.ino
+++ b/examples/MQ-136/MQ-136.ino
@@ -82,7 +82,8 @@ void setup() {
 
 void loop() {
   MQ136.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ136.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ136.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ136.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-2/MQ-2.ino b/examples/MQ-2/MQ-2.ino
index 28ade0c..296fbef 100644
--- a/examples/MQ-2/MQ-2.ino
+++ b/examples/MQ-2/MQ-2.ino
@@ -87,7 +87,8 @@ void setup() {
 
 void loop() {
   MQ2.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ2.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ2.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ2.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-3/MQ-3.ino b/examples/MQ-3/MQ-3.ino
index 1266d8e..9779c73 100644
--- a/examples/MQ-3/MQ-3.ino
+++ b/examples/MQ-3/MQ-3.ino
@@ -88,7 +88,8 @@ void setup() {
 
 void loop() {
   MQ3.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ3.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ3.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ3.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-303A/MQ-303A.ino b/examples/MQ-303A/MQ-303A.ino
index 65c3039..3bd4f40 100644
--- a/examples/MQ-303A/MQ-303A.ino
+++ b/examples/MQ-303A/MQ-303A.ino
@@ -86,7 +86,8 @@ void setup() {
 
 void loop() {
   MQ303.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ303.readSensor(true); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ303.readSensor(true, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ303.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-309A/MQ-309A.ino b/examples/MQ-309A/MQ-309A.ino
index 6141b39..d9d4038 100644
--- a/examples/MQ-309A/MQ-309A.ino
+++ b/examples/MQ-309A/MQ-309A.ino
@@ -95,7 +95,8 @@ void loop() {
     // VH 0.9 Volts
     analogWrite(5, 2); // 255 is 100%, 2.295 is aprox 0.9% of Duty cycle for 60s
     MQ309.update(); // Update data, the arduino will read the voltage from the analog pin
-    MQ309.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+    float correctionFactor = 0; // Optional environmental correction
+    MQ309.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
     MQ309.serialDebug(); // Will print the table on the serial port
     delay(500); //Sampling frequency
   }
@@ -107,7 +108,8 @@ void loop() {
     // VL 0.2 Volts
     analogWrite(5, 1); // 255 is 100%, 0.51 is aprox 0.2% of Duty cycle for 120s
     MQ309.update(); // Update data, the arduino will read the voltage from the analog pin
-    MQ309.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+    float correctionFactor2 = 0; // Optional environmental correction
+    MQ309.readSensor(false, correctionFactor2); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
     MQ309.serialDebug(); // Will print the table on the serial port
     delay(500); //Sampling frequency
   } 
diff --git a/examples/MQ-4-ALL/MQ-4-ALL.ino b/examples/MQ-4-ALL/MQ-4-ALL.ino
index 329e747..b9e48a5 100644
--- a/examples/MQ-4-ALL/MQ-4-ALL.ino
+++ b/examples/MQ-4-ALL/MQ-4-ALL.ino
@@ -79,6 +79,7 @@ void setup() {
 
 void loop() {
   MQ4.update(); // Update data, the arduino will read the voltage from the analog pin
+  float correctionFactor = 0; // Optional environmental correction
   
   /*
     Exponential regression:
@@ -90,19 +91,19 @@ void loop() {
   smoke  | 30000000 | -8.308
   */
   MQ4.setA(3811.9); MQ4.setB(-3.113); // Configure the equation to to calculate CH4 concentration
-  float LPG = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float LPG = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   
   MQ4.setA(1012.7); MQ4.setB(-2.786); // Configure the equation to to calculate CH4 concentration
-  float CH4 = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CH4 = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   
   MQ4.setA(200000000000000); MQ4.setB(-19.05); // Configure the equation to to calculate CH4 concentration
-  float CO = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CO = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   
   MQ4.setA(60000000000); MQ4.setB(-14.01); // Configure the equation to to calculate CH4 concentration
-  float Alcohol = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Alcohol = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   
   MQ4.setA(30000000); MQ4.setB(-8.308); // Configure the equation to to calculate CH4 concentration
-  float Smoke = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Smoke = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   
   Serial.print("|    "); Serial.print(LPG);
   Serial.print("    |    "); Serial.print(CH4);
diff --git a/examples/MQ-4-LINEAR/MQ-4-LINEAR.ino b/examples/MQ-4-LINEAR/MQ-4-LINEAR.ino
index 15a5091..e1f45b4 100644
--- a/examples/MQ-4-LINEAR/MQ-4-LINEAR.ino
+++ b/examples/MQ-4-LINEAR/MQ-4-LINEAR.ino
@@ -81,7 +81,8 @@ void loop() {
   
   //https://jayconsystems.com/blog/understanding-a-gas-sensor 
   MQ4.setA(-0.318); MQ4.setB(1.133); // A -> Slope, B -> Intersect with X - Axis
-  float LPG = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  float LPG = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   //  exposure to 2000 ppm of LPG gas is immediately dangerous to life and health. In this section
   if(LPG>=2000) Serial.println("Warning - Very high concentrations detected!");
diff --git a/examples/MQ-4/MQ-4.ino b/examples/MQ-4/MQ-4.ino
index 0265adc..6341d18 100644
--- a/examples/MQ-4/MQ-4.ino
+++ b/examples/MQ-4/MQ-4.ino
@@ -87,7 +87,8 @@ void setup() {
 
 void loop() {
   MQ4.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ4.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-5/MQ-5.ino b/examples/MQ-5/MQ-5.ino
index add61e9..523b895 100644
--- a/examples/MQ-5/MQ-5.ino
+++ b/examples/MQ-5/MQ-5.ino
@@ -87,7 +87,8 @@ void setup() {
 
 void loop() {
   MQ5.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ5.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ5.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ5.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-6/MQ-6.ino b/examples/MQ-6/MQ-6.ino
index bc8308e..d6f2b13 100644
--- a/examples/MQ-6/MQ-6.ino
+++ b/examples/MQ-6/MQ-6.ino
@@ -87,7 +87,8 @@ void setup() {
 
 void loop() {
   MQ6.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ6.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ6.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ6.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-7/MQ-7.ino b/examples/MQ-7/MQ-7.ino
index 5a7eace..5da676a 100644
--- a/examples/MQ-7/MQ-7.ino
+++ b/examples/MQ-7/MQ-7.ino
@@ -100,7 +100,8 @@ void loop() {
     // VH 5 Volts
     analogWrite(5, 255); // 255 is DC 5V output
     MQ7.update(); // Update data, the arduino will read the voltage from the analog pin
-    MQ7.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+    float correctionFactor = 0; // Optional environmental correction
+    MQ7.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
     MQ7.serialDebug(); // Will print the table on the serial port
     delay(500); //Sampling frequency
   }
@@ -112,7 +113,8 @@ void loop() {
     // VH 1.4 Volts
     analogWrite(5, 20); // 255 is 100%, 20.4 is aprox 8% of Duty cycle for 90s
     MQ7.update(); // Update data, the arduino will read the voltage from the analog pin
-    MQ7.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+    float correctionFactor2 = 0; // Optional environmental correction
+    MQ7.readSensor(false, correctionFactor2); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
     MQ7.serialDebug(); // Will print the table on the serial port
     delay(500); //Sampling frequency
   } 
diff --git a/examples/MQ-8/MQ-8.ino b/examples/MQ-8/MQ-8.ino
index 14658d3..2f91b32 100644
--- a/examples/MQ-8/MQ-8.ino
+++ b/examples/MQ-8/MQ-8.ino
@@ -88,7 +88,8 @@ void setup() {
 
 void loop() {
   MQ8.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ8.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ8.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ8.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/MQ-9-ALL/MQ-9-ALL.ino b/examples/MQ-9-ALL/MQ-9-ALL.ino
index 57ea32b..d1c7b14 100644
--- a/examples/MQ-9-ALL/MQ-9-ALL.ino
+++ b/examples/MQ-9-ALL/MQ-9-ALL.ino
@@ -78,6 +78,7 @@ void setup() {
 
 void loop() {
   MQ9.update(); // Update data, the arduino will read the voltage from the analog pin
+  float correctionFactor = 0; // Optional environmental correction
   /*
   Exponential regression:
   GAS     | a      | b
@@ -87,13 +88,13 @@ void loop() {
   */
 
   MQ9.setA(1000.5); MQ9.setB(-2.186); // Configure the equation to to calculate LPG concentration
-  float LPG = MQ9.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float LPG = MQ9.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ9.setA(4269.6); MQ9.setB(-2.648); // Configure the equation to to calculate LPG concentration
-  float CH4 = MQ9.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CH4 = MQ9.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ9.setA(599.65); MQ9.setB(-2.244); // Configure the equation to to calculate LPG concentration
-  float CO = MQ9.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CO = MQ9.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   Serial.print("|    "); Serial.print(LPG);
   Serial.print("    |    "); Serial.print(CH4);
diff --git a/examples/MQ-9/MQ-9.ino b/examples/MQ-9/MQ-9.ino
index d7c3197..595c50a 100644
--- a/examples/MQ-9/MQ-9.ino
+++ b/examples/MQ-9/MQ-9.ino
@@ -115,7 +115,8 @@ void loop() {
   digitalWrite(PreaheatControlPin14, LOW);
   
   MQ9.update(); // Update data, the arduino will read the voltage from the analog pin
-  MQ9.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ9.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ9.serialDebug(); // Will print the table on the serial port
   
 }
\ No newline at end of file
diff --git a/examples/MQ-Board/MQ-Board.ino b/examples/MQ-Board/MQ-Board.ino
index be2b3ee..ce78fce 100644
--- a/examples/MQ-Board/MQ-Board.ino
+++ b/examples/MQ-Board/MQ-Board.ino
@@ -201,15 +201,16 @@ void readAllSensors()
   MQ7.update();
   MQ8.update();
   MQ9.update();
+  float correctionFactor = 0; // Optional environmental correction
   //Read the sensor and print in serial port
-  float MQ2Lecture =  MQ2.readSensor();
-  float MQ3Lecture =  MQ3.readSensor();
-  float MQ4Lecture =  MQ4.readSensor();
-  float MQ5Lecture =  MQ5.readSensor();
-  float MQ6Lecture =  MQ6.readSensor();
-  float MQ7Lecture =  MQ7.readSensor();
-  float MQ8Lecture =  MQ8.readSensor();
-  float MQ9Lecture =  MQ9.readSensor();
+  float MQ2Lecture =  MQ2.readSensor(false, correctionFactor);
+  float MQ3Lecture =  MQ3.readSensor(false, correctionFactor);
+  float MQ4Lecture =  MQ4.readSensor(false, correctionFactor);
+  float MQ5Lecture =  MQ5.readSensor(false, correctionFactor);
+  float MQ6Lecture =  MQ6.readSensor(false, correctionFactor);
+  float MQ7Lecture =  MQ7.readSensor(false, correctionFactor);
+  float MQ8Lecture =  MQ8.readSensor(false, correctionFactor);
+  float MQ9Lecture =  MQ9.readSensor(false, correctionFactor);
 
   Serial.print("| "); Serial.print(MQ2Lecture);
   Serial.print("   |   "); Serial.print(MQ3Lecture);
diff --git a/examples/MQ135-ADS1115/MQ135-ADS1115.ino b/examples/MQ135-ADS1115/MQ135-ADS1115.ino
index 0a2aded..2a4dc3a 100644
--- a/examples/MQ135-ADS1115/MQ135-ADS1115.ino
+++ b/examples/MQ135-ADS1115/MQ135-ADS1115.ino
@@ -74,24 +74,25 @@ void loop() {
   short adc0 = ads.readADC_SingleEnded(0);
   float voltios = (adc0 * factorEscala)/1000.0;
   MQ135.externalADCUpdate(voltios); // Update data, the arduino will read the voltage from the analog pin
+  float correctionFactor = 0; // Optional environmental correction
 
   MQ135.setA(605.18); MQ135.setB(-3.937); // Configure the equation to calculate CO concentration value
-  float CO = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CO = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(77.255); MQ135.setB(-3.18); //Configure the equation to calculate Alcohol concentration value
-  float Alcohol = MQ135.readSensor(); // SSensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Alcohol = MQ135.readSensor(false, correctionFactor); // SSensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(110.47); MQ135.setB(-2.862); // Configure the equation to calculate CO2 concentration value
-  float CO2 = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float CO2 = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(44.947); MQ135.setB(-3.445); // Configure the equation to calculate Toluen concentration value
-  float Toluen = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Toluen = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(102.2 ); MQ135.setB(-2.473); // Configure the equation to calculate NH4 concentration value
-  float NH4 = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float NH4 = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
 
   MQ135.setA(34.668); MQ135.setB(-3.369); // Configure the equation to calculate Aceton concentration value
-  float Aceton = MQ135.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float Aceton = MQ135.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   Serial.print("|   "); Serial.print(CO); 
   Serial.print("   |   "); Serial.print(Alcohol);
   // Note: 200 Offset for CO2 source: https://github.com/miguel5612/MQSensorsLib/issues/29
diff --git a/examples/UnitTesting/UnitTesting.ino b/examples/UnitTesting/UnitTesting.ino
index 67322b8..9fd8569 100644
--- a/examples/UnitTesting/UnitTesting.ino
+++ b/examples/UnitTesting/UnitTesting.ino
@@ -251,7 +251,8 @@ test(MQ303A_VoltResolution)
   float vRes = 4.7;
   MQ303A.setVoltResolution(vRes);
   MQ303A.setADC(100);            // provide dummy ADC value
-  MQ303A.readSensor(true);       // dummy read for MQ303A
+  float correctionFactor = 0; // Optional environmental correction
+  MQ303A.readSensor(true, correctionFactor);       // dummy read for MQ303A
   assertEqualFloat(MQ303A.getVoltResolution(), vRes);
 }
 
diff --git a/examples/external_A2D/external_A2D.ino b/examples/external_A2D/external_A2D.ino
index b3249e9..6f2938a 100644
--- a/examples/external_A2D/external_A2D.ino
+++ b/examples/external_A2D/external_A2D.ino
@@ -99,7 +99,8 @@ void setup() {
 void loop() {
   int yourA2DValue = random(0, 1024); // 10-bit emulation
   MQ3.setADC(yourA2DValue); // Update data, the arduino will read the voltage from the analog pin
-  MQ3.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  MQ3.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   MQ3.serialDebug(); // Will print the table on the serial port
   delay(500); //Sampling frequency
 }
\ No newline at end of file
diff --git a/examples/smokeDetector/smokeDetector.ino b/examples/smokeDetector/smokeDetector.ino
index 60e52a4..17b8fe9 100644
--- a/examples/smokeDetector/smokeDetector.ino
+++ b/examples/smokeDetector/smokeDetector.ino
@@ -88,7 +88,8 @@ void setup() {
   //Read the sensor and print in serial port
   //Lecture will be saved in lecture variable
   MQ4.update();
-  float smokePPM = MQ4.readSensor(); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
+  float correctionFactor = 0; // Optional environmental correction
+  float smokePPM = MQ4.readSensor(false, correctionFactor); // Sensor will read PPM concentration using the model, a and b values set previously or from the setup
   if(smokePPM > 1000) {Serial.println("Warning: High concentrations of smoke detected");}
   MQ4.serialDebug(); // Will print the table on the serial port
   delay(400);  
diff --git a/library.properties b/library.properties
index b1e7c3a..1100483 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=MQUnifiedsensor
-version=3.0.3
+version=3.0.5
 author= Miguel Califa <miguelangel5612@gmail.com>, Yersson Carrillo<miguelangel5612@gmail.com>, Ghiordy Contreras<miguelangel5612@gmail.com>
 maintainer= Miguel Califa <miguelangel5612@gmail.com>
 sentence= This library allows you to read the MQ sensors very easily.
diff --git a/src/MQUnifiedsensor.cpp b/src/MQUnifiedsensor.cpp
index b484c41..5b282c7 100644
--- a/src/MQUnifiedsensor.cpp
+++ b/src/MQUnifiedsensor.cpp
@@ -215,12 +215,13 @@ float MQUnifiedsensor::readSensor(bool isMQ303A, float correctionFactor, bool in
   //if(_PPM > 10000) _PPM = 99999999; //No negative values accepted or upper datasheet recommendation.
   return _PPM;
 }
-float MQUnifiedsensor::readSensorR0Rs()
+float MQUnifiedsensor::readSensorR0Rs(float correctionFactor)
 {
   //More explained in: https://jayconsystems.com/blog/understanding-a-gas-sensor
   _RS_Calc = ((_VCC*_RL)/_sensor_volt)-_RL; //Get value of RS in a gas
   if(_RS_Calc < 0)  _RS_Calc = 0; //No negative values accepted.
   _ratio = this->_R0/_RS_Calc;   // Get ratio RS_air/RS_gas <- INVERTED for MQ-131 issue 28 https://github.com/miguel5612/MQSensorsLib/issues/28
+  _ratio += correctionFactor;
   if(_ratio <= 0)  _ratio = 0; //No negative values accepted or upper datasheet recommendation.
   double ppm;
   if(_regressionMethod == 1){
@@ -242,7 +243,7 @@ float MQUnifiedsensor::readSensorR0Rs()
   //if(_PPM > 10000) _PPM = 99999999; //No negative values accepted or upper datasheet recommendation.
   return _PPM;
 }
-float MQUnifiedsensor::calibrate(float ratioInCleanAir) {
+float MQUnifiedsensor::calibrate(float ratioInCleanAir, float correctionFactor) {
   //More explained in: https://jayconsystems.com/blog/understanding-a-gas-sensor
   /*
   V = I x R 
@@ -259,7 +260,8 @@ float MQUnifiedsensor::calibrate(float ratioInCleanAir) {
   float R0; //Define variable for R0
   RS_air = ((_VCC*_RL)/_sensor_volt)-_RL; //Calculate RS in fresh air
   if(RS_air < 0)  RS_air = 0; //No negative values accepted.
-  R0 = RS_air/ratioInCleanAir; //Calculate R0 
+  R0 = RS_air/ratioInCleanAir; //Calculate R0
+  R0 += correctionFactor;
   if(R0 < 0)  R0 = 0; //No negative values accepted.
   return R0;
 }
diff --git a/src/MQUnifiedsensor.h b/src/MQUnifiedsensor.h
index 24874c2..11637c2 100644
--- a/src/MQUnifiedsensor.h
+++ b/src/MQUnifiedsensor.h
@@ -34,9 +34,9 @@ class MQUnifiedsensor
     void setADC(int value); //For external ADC Usage
     
     //user functions
-    float calibrate(float ratioInCleanAir);
+    float calibrate(float ratioInCleanAir, float correctionFactor = 0.0);
     float readSensor(bool isMQ303A = false, float correctionFactor = 0.0, bool injected=false);
-    float readSensorR0Rs();
+    float readSensorR0Rs(float correctionFactor = 0.0);
     float validateEcuation(float ratioInput = 0);
     
     //get function for info