Smoke/Gas Leakage Indicator or Alarm

#include<LiquidCrystal.h>
const int rs=2,en=3,d4=4,d5=5,d6=6,d7=7;
LiquidCrystal lcd(rs,en,d4,d5,d6,d7); 
const int red=8,green=10;
int i;
void setup() {
lcd.begin(16,2);
pinMode(green,OUTPUT);
pinMode(red,OUTPUT);
pinMode(9,INPUT);  
lcd.setCursor(0,0);
lcd.print("smoke Detector");  
}

void loop() {


if(digitalRead(9)==1)
{
  digitalWrite(green,LOW);
  digitalWrite(red,HIGH);
  lcd.setCursor(0,1);
  lcd.print("Smoke Detected");
}

else
{
  digitalWrite(green,HIGH);
  digitalWrite(red,LOW);
  lcd.setCursor(0,1);
  lcd.print("No smoke detted ");
}


}