BME680 gas sensor's value keeps increasing - arduino

Question

I've been trying to get the BME680 to work and for the most part it seems to be working great. I do have one issue and that is with the gas sensor.
I write all the contents of the BME680 out to a webpage and all of the other values remain consistent.
Temperature: 77.29 *F
Humidity: 59.12 %
Pressure: 1010.45 millibars
Air Quality: 3.24 KOhms
On every refresh of the page the values for Temperature, Humidity, and Pressure all remain close to their values. They correct for a little while and show the minor fluctuations correctly. When it starts to rain the pressure goes down, the humidity goes up, etc... The issue is the Gas Sensor. On ever refresh the value keeps increasing. Regardless of whether I refresh it once per minute or per hour it keeps increasing. I'm clearly doing something wrong.
#include <Wire.h>
#include <SPI.h>
#include <Adafruit_Sensor.h>
#include "Adafruit_BME680.h"
#include <WiFi101.h>
#include <WiFiUdp.h>
#include "arduino_secrets.h"
///////please enter your sensitive data in the Secret tab/arduino_secrets.h
char ssid[] = SECRET_SSID; // your network SSID (name)
char pass[] = SECRET_PASS; // your network password (use for WPA, or use as key for WEP)
int keyIndex = 0; // your network key Index number (needed only for WEP)
int status = WL_IDLE_STATUS;
WiFiServer server(80);
#define SEALEVELPRESSURE_HPA (1023.03)
Adafruit_BME680 bme; // I2C
void setup() {
//Serial.begin(9600);
pinMode(LED_BUILTIN, OUTPUT); // set the LED pin mode
bme.begin();
// Set up oversampling and filter initialization
bme.setTemperatureOversampling(BME680_OS_8X);
bme.setHumidityOversampling(BME680_OS_2X);
bme.setPressureOversampling(BME680_OS_4X);
bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
bme.setGasHeater(320, 150); // 320*C for 150 ms
// check for the presence of the shield:
if (WiFi.status() == WL_NO_SHIELD) {
//Serial.println("WiFi shield not present");
while (true); // don't continue
}
// attempt to connect to WiFi network:
while ( status != WL_CONNECTED) {
// Connect to WPA/WPA2 network. Change this line if using open or WEP network:
status = WiFi.begin(ssid, pass);
// wait 10 seconds for connection:
delay(10000);
}
server.begin(); // start the web server on port 80
}
void loop() {
WiFiClient client = server.available(); // listen for incoming clients
if (client) { // if you get a client,
//Serial.println("new client"); // print a message out the serial port
String currentLine = ""; // make a String to hold incoming data from the client
while (client.connected()) { // loop while the client's connected
if (client.available()) { // if there's bytes to read from the client,
char c = client.read(); // read a byte, then
//Serial.write(c); // print it out the serial monitor
if (c == '\n') { // if the byte is a newline character
// if the current line is blank, you got two newline characters in a row.
// that's the end of the client HTTP request, so send a response:
if (currentLine.length() == 0) {
// HTTP headers always start with a response code (e.g. HTTP/1.1 200 OK)
// and a content-type so the client knows what's coming, then a blank line:
client.println("HTTP/1.1 200 OK");
client.println("Content-type:text/html");
client.println();
if (! bme.performReading()) {
client.print("Failed to perform reading :(<br>");
return;
}
// the current weather condidtions
client.print("Temperature: ");
client.print((bme.temperature * 9/5) + 32);
client.print(" *F<br>");
client.print("Humidity: ");
client.print(bme.humidity);
client.print(" %<br>");
client.print("Pressure: ");
client.print(bme.pressure / 100.0);
client.print(" millibars<br>");
client.print("Air Quality: ");
client.print(bme.gas_resistance / 1000.0);
client.print(" KOhms<br>");
delay(2000);
// The HTTP response ends with another blank line:
client.println();
// break out of the while loop:
break;
}
else { // if you got a newline, then clear currentLine:
currentLine = "";
}
}
else if (c != '\r') { // if you got anything else but a carriage return character,
currentLine += c; // add it to the end of the currentLine
}
}
}
// close the connection:
client.stop();
//Serial.println("client disonnected");
}
}

Answer 1

I see two important points. Two for the beginning. Missing the ambient temperature and the sea-level.
Default ambient is: 25deg.C
Default sea-level is: 500 meter
Add this with correct values to your code. Then you have todo some automatic calibrations after burn in time. My own experience is that 2 weeks 24/7 is needed to get the sensor much old as needed. Next step look in the BOSCH original library and example code. Then start over again. Currently i'm rewriting the driver for the BME and BMP series for Tasmota (github). Lot's of work believe me. And i'm from the physics and chemical side. So some research helps always.