diff --git a/MQ135.cpp b/MQ135.cpp
old mode 100755
new mode 100644
index 676ed31..70d5393
--- a/MQ135.cpp
+++ b/MQ135.cpp
@@ -27,49 +27,66 @@ v1.0 - First release
 MQ135::MQ135(uint8_t pin) {
   _pin = pin;
 }
-
-
 /**************************************************************************/
 /*!
-@brief  Get the correction factor to correct for temperature and humidity
-
-@param[in] t  The ambient air temperature
-@param[in] h  The relative humidity
+@brief  Get the resistance of the sensor, ie. the measurement value
 
-@return The calculated correction factor
+@return The sensor resistance in Ohms
 */
 /**************************************************************************/
-float MQ135::getCorrectionFactor(float t, float h) {
-  return CORA * t * t - CORB * t + CORC - (h-33.)*CORD;
+float MQ135::getResistance() {
+  int val = analogRead(_pin);
+  return ((1024./(float)val) * 5. - 1.)*RLOAD;
 }
-
 /**************************************************************************/
 /*!
-@brief  Get the resistance of the sensor, ie. the measurement value
-
-@return The sensor resistance in kOhm
+@brief  Get the ppm of CO sensed
+@return ppm value of CO in air
 */
 /**************************************************************************/
-float MQ135::getResistance() {
-  int val = analogRead(_pin);
-  return ((1023./(float)val) * 5. - 1.)*RLOAD;
+float MQ135::getCOPPM() {
+  return scaleFactorCO * pow((getResistance()/r0CO), -exponentCO);
 }
+/**************************************************************************/
+/*!
+@brief  Get the ppm of CO2 sensed (assuming only CO2 in the air)
 
+@return The ppm of CO2 in the air
+*/
+/**************************************************************************/
+float MQ135::getCO2PPM() {
+  return scaleFactorCO2 * pow((getResistance()/r0CO2), -exponentCO2);
+}
 /**************************************************************************/
 /*!
-@brief  Get the resistance of the sensor, ie. the measurement value corrected
-        for temp/hum
+@brief  Get the ppm of Ethanol sensed 
 
-@param[in] t  The ambient air temperature
-@param[in] h  The relative humidity
+@return The ppm of Ethanol in the air
+*/
+/**************************************************************************/
+float MQ135::getEthanolPPM() {
+  return scaleFactorEthanol * pow((getResistance()/r0Ethanol), -exponentEthanol);
+}
+/**************************************************************************/
+/*!
+@brief  Get the ppm of NH4 sensed 
 
-@return The corrected sensor resistance kOhm
+@return The ppm of NH4 in the air
 */
 /**************************************************************************/
-float MQ135::getCorrectedResistance(float t, float h) {
-  return getResistance()/getCorrectionFactor(t, h);
+float MQ135::getNH4PPM() {
+  return scaleFactorNH4 * pow((getResistance()/r0NH4), -exponentNH4);
 }
+/**************************************************************************/
+/*!
+@brief  Get the ppm of CO2 sensed (assuming only CO2 in the air)
 
+@return The ppm of CO2 in the air
+*/
+/**************************************************************************/
+float MQ135::getToluenePPM() {
+  return scaleFactorToluene * pow((getResistance()/r0Toluene), -exponentToluene);
+}
 /**************************************************************************/
 /*!
 @brief  Get the ppm of CO2 sensed (assuming only CO2 in the air)
@@ -77,25 +94,59 @@ float MQ135::getCorrectedResistance(float t, float h) {
 @return The ppm of CO2 in the air
 */
 /**************************************************************************/
-float MQ135::getPPM() {
-  return PARA * pow((getResistance()/RZERO), -PARB);
+float MQ135::getAcetonePPM() {
+  return scaleFactorAcetone * pow((getResistance()/r0Acetone), -exponentAcetone);
 }
+/**************************************************************************/
+/*!
+@brief  Get the resistance RZero of the sensor for calibration purposes
 
+@return The sensor resistance RZero in kOhm
+*/
+/**************************************************************************/
+float MQ135::getRZeroCO() {
+  return getResistance() * pow((atmCO/scaleFactorCO), (1./exponentCO));
+}
 /**************************************************************************/
 /*!
-@brief  Get the ppm of CO2 sensed (assuming only CO2 in the air), corrected
-        for temp/hum
+@brief  Get the resistance RZero of the sensor for calibration purposes
 
-@param[in] t  The ambient air temperature
-@param[in] h  The relative humidity
+@return The sensor resistance RZero in kOhm
+*/
+/**************************************************************************/
+float MQ135::getRZeroCO2() {
+  return getResistance() * pow((atmCO2/scaleFactorCO2), (1./exponentCO2));
+}
+/**************************************************************************/
+/*!
+@brief  Get the resistance RZero of the sensor for calibration purposes
 
-@return The ppm of CO2 in the air
+@return The sensor resistance RZero in kOhm
+*/
+/**************************************************************************/
+float MQ135::getRZeroEthanol() {
+  return getResistance() * pow((atmEthanol/scaleFactorEthanol), (1./exponentEthanol));
+}
+/**************************************************************************/
+/*!
+@brief  Get the resistance RZero of the sensor for calibration purposes
+
+@return The sensor resistance RZero in kOhm
 */
 /**************************************************************************/
-float MQ135::getCorrectedPPM(float t, float h) {
-  return PARA * pow((getCorrectedResistance(t, h)/RZERO), -PARB);
+float MQ135::getRZeroNH4() {
+  return getResistance() * pow((atmNH4/scaleFactorNH4), (1./exponentNH4));
 }
+/**************************************************************************/
+/*!
+@brief  Get the resistance RZero of the sensor for calibration purposes
 
+@return The sensor resistance RZero in kOhm
+*/
+/**************************************************************************/
+float MQ135::getRZeroToluene() {
+  return getResistance() * pow((atmToluene/scaleFactorToluene), (1./exponentToluene));
+}
 /**************************************************************************/
 /*!
 @brief  Get the resistance RZero of the sensor for calibration purposes
@@ -103,21 +154,111 @@ float MQ135::getCorrectedPPM(float t, float h) {
 @return The sensor resistance RZero in kOhm
 */
 /**************************************************************************/
-float MQ135::getRZero() {
-  return getResistance() * pow((ATMOCO2/PARA), (1./PARB));
+float MQ135::getRZeroAcetone() {
+  return getResistance() * pow((atmAcetone/scaleFactorAcetone), (1./exponentAcetone));
 }
+/**************************************************************************/
+/*!
+@brief  Get the ppm of CO sensed
+@return ppm value of CO in air
+*/
+/**************************************************************************/
+float MQ135::getCO(float res) {
+  return scaleFactorCO * pow((res/r0CO), -exponentCO);
+}
+/**************************************************************************/
+/*!
+@brief  Get the ppm of CO2 sensed (assuming only CO2 in the air)
 
+@return The ppm of CO2 in the air
+*/
+/**************************************************************************/
+float MQ135::getCO2(float res) {
+  return scaleFactorCO2 * pow((res/r0CO2), -exponentCO2);
+}
 /**************************************************************************/
 /*!
-@brief  Get the corrected resistance RZero of the sensor for calibration
-        purposes
+@brief  Get the ppm of Ethanol sensed 
 
-@param[in] t  The ambient air temperature
-@param[in] h  The relative humidity
+@return The ppm of Ethanol in the air
+*/
+/**************************************************************************/
+float MQ135::getEthanol(float res) {
+  return scaleFactorEthanol * pow((res/r0Ethanol), -exponentEthanol);
+}
+/**************************************************************************/
+/*!
+@brief  Get the ppm of NH4 sensed 
 
-@return The corrected sensor resistance RZero in kOhm
+@return The ppm of NH4 in the air
 */
 /**************************************************************************/
-float MQ135::getCorrectedRZero(float t, float h) {
-  return getCorrectedResistance(t, h) * pow((ATMOCO2/PARA), (1./PARB));
+float MQ135::getNH4(float res) {
+  return scaleFactorNH4 * pow((res/r0NH4), -exponentNH4);
+}
+/**************************************************************************/
+/*!
+@brief  Get the ppm of CO2 sensed (assuming only CO2 in the air)
+
+@return The ppm of CO2 in the air
+*/
+/**************************************************************************/
+float MQ135::getToluene(float res) {
+  return scaleFactorToluene * pow((res/r0Toluene), -exponentToluene);
+}
+/**************************************************************************/
+/*!
+@brief  Get the ppm of CO2 sensed (assuming only CO2 in the air)
+
+@return The ppm of CO2 in the air
+*/
+/**************************************************************************/
+float MQ135::getAcetone(float res) {
+  return scaleFactorAcetone * pow((res/r0Acetone), -exponentAcetone);
+}
+/* RETURN THE RZERO WITH A PARAMETER OF RESISTANCE*/
+float MQ135::getCorrectedRZero(float r) {
+  return r * pow((atmCO2/scaleFactorCO2), (1./exponentCO2));
+}
+float MQ135::getCorrectedRZeroCO(float r) {
+  return r * pow((atmCO/scaleFactorCO), (1./exponentCO));
+}
+float MQ135::getCorrectedRZeroEthanol(float r) {
+  return r * pow((atmEthanol/scaleFactorEthanol), (1./exponentEthanol));
+}
+float MQ135::getCorrectedRZeroNH4(float r) {
+  return r * pow((atmNH4/scaleFactorNH4), (1./exponentNH4));
+}
+float MQ135::getCorrectedRZeroToluene(float r) {
+  return r * pow((atmToluene/scaleFactorToluene), (1./exponentToluene));
+}
+float MQ135::getCorrectedRZeroAcetone(float r) {
+  return r * pow((atmAcetone/scaleFactorAcetone), (1./exponentAcetone));
+}
+/*CORRECTED RESISTANCE*/
+float MQ135::getCorrectedResistance(float t, float h) {
+  return getResistance()/getCorrectionFactor(t, h);
+}
+/*CORRECTION FACTOR*/
+float MQ135::getCorrectionFactor(float t, float h) {
+  return CORA * t * t - CORB * t + CORC - (h-33.)*CORD;
+}
+
+float MQ135::getCalibratedCO2(float t, float h){
+  return scaleFactorCO2 * pow((getCorrectedResistance(t, h)/getCorrectedRZero(getCorrectedResistance(t, h))), -exponentCO2);
+}
+float MQ135::getCalibratedCO(float t, float h) {
+  return scaleFactorCO * pow((getCorrectedResistance(t, h)/getCorrectedRZeroCO(getCorrectedResistance(t, h))), -exponentCO);
+}
+float MQ135::getCalibratedEthanol(float t, float h) {
+  return scaleFactorEthanol * pow((getCorrectedResistance(t, h)/getCorrectedRZeroEthanol(getCorrectedResistance(t, h))), -exponentEthanol);
+}
+float MQ135::getCalibratedNH4(float t, float h) {
+  return scaleFactorNH4 * pow((getCorrectedResistance(t, h)/getCorrectedRZeroNH4(getCorrectedResistance(t, h))), -exponentNH4);
+}
+float MQ135::getCalibratedToluene(float t, float h) {
+  return scaleFactorToluene * pow((getCorrectedResistance(t, h)/getCorrectedRZeroToluene(getCorrectedResistance(t, h))), -exponentToluene);
+}
+float MQ135::getCalibratedAcetone(float t, float h) {
+  return scaleFactorAcetone * pow((getCorrectedResistance(t, h)/getCorrectedRZeroAcetone(getCorrectedResistance(t, h))), -exponentAcetone);
 }
diff --git a/MQ135.h b/MQ135.h
old mode 100755
new mode 100644
index 22cefec..6304556
--- a/MQ135.h
+++ b/MQ135.h
@@ -1,55 +1,125 @@
-/**************************************************************************/
-/*!
-@file     MQ135.h
-@author   G.Krocker (Mad Frog Labs)
-@license  GNU GPLv3
-
-First version of an Arduino Library for the MQ135 gas sensor
-TODO: Review the correction factor calculation. This currently relies on
-the datasheet but the information there seems to be wrong.
-
-@section  HISTORY
-
-v1.0 - First release
-*/
-/**************************************************************************/
-#ifndef MQ135_H
-#define MQ135_H
-#if ARDUINO >= 100
- #include "Arduino.h"
-#else
- #include "WProgram.h"
-#endif
-
-/// The load resistance on the board
-#define RLOAD 10.0
-/// Calibration resistance at atmospheric CO2 level
-#define RZERO 76.63
-/// Parameters for calculating ppm of CO2 from sensor resistance
-#define PARA 116.6020682
-#define PARB 2.769034857
-
-/// Parameters to model temperature and humidity dependence
-#define CORA 0.00035
-#define CORB 0.02718
-#define CORC 1.39538
-#define CORD 0.0018
-
-/// Atmospheric CO2 level for calibration purposes
-#define ATMOCO2 397.13
-
-class MQ135 {
- private:
-  uint8_t _pin;
-
- public:
-  MQ135(uint8_t pin);
-  float getCorrectionFactor(float t, float h);
-  float getResistance();
-  float getCorrectedResistance(float t, float h);
-  float getPPM();
-  float getCorrectedPPM(float t, float h);
-  float getRZero();
-  float getCorrectedRZero(float t, float h);
-};
-#endif
+/**************************************************************************/
+/*!
+@file     MQ135.h
+@author   G.Krocker (Mad Frog Labs)
+@license  GNU GPLv3
+
+First version of an Arduino Library for the MQ135 gas sensor
+TODO: Review the correction factor calculation. This currently relies on
+the datasheet but the information there seems to be wrong.
+
+@section  HISTORY
+
+v1.0 - First release
+*/
+/**************************************************************************/
+#ifndef MQ135_H
+#define MQ135_H
+#if ARDUINO >= 100
+ #include "Arduino.h"
+#else
+ #include "WProgram.h"
+#endif
+
+/// To convert readed resistance into ohms
+#define RLOAD 10.0
+/// R0 for AIR
+#define r0Air 1
+/// R0 for CO **measured with 24hrs of exposure**
+#define r0CO 69.65
+/// R0 for CO2 **realized 24 hrs of exposure**
+#define r0CO2 553.232
+/// R0 for Ethanol **measured with 24hrs of exposure**
+#define r0Ethanol 240.293
+/// R0 for Ammonium **measured with 24hrs of exposure**
+#define r0NH4 164.8282
+/// R0 for Toluene **measured with 24hrs of exposure**
+#define r0Toluene 130.726
+/// R0 for Acetone **measured with 24hrs of exposure**
+#define r0Acetone 224.6261
+/// Parameters Equation for CO
+#define scaleFactorCO 662.9382
+#define exponentCO 4.0241
+/// Parameters Equation for CO2
+#define scaleFactorCO2 116.6020682
+#define exponentCO2 2.769034857
+///	Paremeters Equation for Ethanol
+#define scaleFactorEthanol 75.3103
+#define exponentEthanol 3.1459
+/// Parameters Equation for NH4
+#define scaleFactorNH4 102.694
+#define exponentNH4 2.48818
+/// Parameters Equation for Toluene
+#define scaleFactorToluene 43.7748
+#define exponentToluene 3.42936
+/// Parameters Equation for Acetone
+#define scaleFactorAcetone 33.1197
+#define exponentAcetone 3.36587
+/// Parameters to model temperature and humidity dependence
+#define CORA 0.00035
+#define CORB 0.02718
+#define CORC 1.39538
+#define CORD 0.0018
+/// Atmospheric CO Level for calibration purposes
+#define atmCO 1
+/// Atmospheric CO2 level for calibration purposes
+#define atmCO2 407.57
+/// Atmospheric Ethanol Level for calibration purposes https://www.mathesongas.com/pdfs/msds/00224106.pdf
+#define atmEthanol 22.5
+/// Atmospheric NH4 level for calibration purposes
+#define atmNH4 15
+/// Atmospheric Toluene level for calibration purposes
+#define atmToluene 2.9
+/// Atmospheric Acetone level for calibration purposes
+#define atmAcetone 16
+
+class MQ135 {
+ private:
+  uint8_t _pin;
+
+ public:
+  MQ135(uint8_t pin);
+  float getResistance();
+  
+  float getCOPPM();
+  float getCO2PPM();
+  float getEthanolPPM();
+  float getNH4PPM();
+  float getToluenePPM();
+  float getAcetonePPM();
+  
+  float getRZeroCO();
+  float getRZeroCO2();
+  float getRZeroEthanol();
+  float getRZeroNH4();
+  float getRZeroToluene();
+  float getRZeroAcetone();
+  
+  float getCO(float res);
+  float getCO2(float res);
+  float getEthanol(float res);
+  float getNH4(float res);
+  float getToluene(float res);
+  float getAcetone(float res);
+  
+  
+  float getCorrectedRZero(float r);
+  float getCorrectedRZeroCO(float r);
+  float getCorrectedRZeroEthanol(float r);
+  float getCorrectedRZeroNH4(float r);
+  float getCorrectedRZeroToluene(float r);
+  float getCorrectedRZeroAcetone(float r);
+  
+  float getCorrectedResistance(float t, float h);
+  float getCorrectionFactor(float t, float h);
+  
+  float getCalibratedCO2(float t, float h);
+  float getCalibratedCO(float t, float h);
+  float getCalibratedEthanol(float t, float h);
+  float getCalibratedNH4(float t, float h);
+  float getCalibratedToluene(float t, float h);
+  float getCalibratedAcetone(float t, float h);
+
+
+};
+#endif