Dust sensor code with a few errors
You have to use the begin command. Instead of:

SDS011(byte pin_rx, byte pin_tx)  

...

SDS011 my_sds;


Use

SDS011 my_sds;


(Thus remove the first line: SDS011(byte pin_rx, byte pin_tx)).

And in setup add:

my_sds.begin(0, 1);


This follows the library function of SDS011:

void begin(uint8_t pin_rx, uint8_t pin_tx);


Other errors: because you forgot the ; in

SDS011(byte pin_rx, byte pin_tx) 


the next line:

float p10,p25;


is misinterpreted, and p10 and p25 are not known. Therefore errors are shown while trying to use p10 and p25.

These errors will go when changing the begin code as described earlier.