AirQuality source code is confusing

I currently working on Intel Edison, and have Grove Air Quality Sensor v1.1

Problem1 recreation:
Downloading the source, and install to Arduino library(Arduino IDEdownloaded from intel). Open the example, start Verify. And errors:

It seems that IDE doesn’t know about the function: ISR(TIMER2_OVF_vect).
I googled it and found it, it’s a kind of interrupt, and the source is just make sure every 2 seconds update the value.
So I rewrote this part using loop, delay 0.1 seconds and update every 20 times. But compiler reports:

So I commented out them, and recompile, finally it works!
Guys, can you run the examples without modification?

In the example source, it called airqualitysensor.init(14); in setup(). So this sensor should be connected to A0.
But AirQuality.cpp’s void AirQuality::init(int pin) function is built-in first_vol=analogRead(A0);//initialize first value which means it just read A0 even if you set to A1 pin.
This should not a problem, due to the value would be changed after 2 seconds(why 122 means 2 seconds?)
And why use interrupts to update the value?

Sorry for delayed reply. Air Quality library currently works on AVR based Arduino. This is the reason for many compiler errors.

All these are AVR GCC specific code :

//init the timer 
TCCR2A=0;//normal model
TCCR2B=0x07;//set clock as 1024*(1/16M)
TIMSK2=0x01;//enable overflow interrupt
Serial.println("Test begin...");

The sensor itself is just an Analog output. The Arduino Libray provided sets certain thresholds to detect the quality of Air. I think the original author used periodic sampling to average-out the output from the sensor. This is also to filter the raw analog value.

We will improve the existing documentation for Grove Air quality-sensor

Let me know if you need any further information.

I wanted use Grov- Air Quality Sensor V1.3 with udoo neo with Base shield v2 (connect A2) , but cannot use example from Seeedstudio site and github. Error (ISR (TIMER2_OVF_vect ). Why? Thanks.