hello, so i had a question, does the GP2Y1014AU0F sensor measure pm2.5 and pm10 ? one of them or both of them ???
i searched about pm2.5 sensor module in internet 
do you know the ranges for DSM501A sensor??
There is also no specification in the datasheet either.
Only this:
The datasheet can be found at Elecrow: https://wiki.elecrow.com/index.php?title=File:DSM501.pdf
so it can measure 2.5 and 10 pm
??
If it detect particles bigger than one micrometer, then it detects particles smaller than 2.5µm and 10µm particles. However, that is not specifically mentioned in the datasheet.
You are looking at sensors for indoor home usage.
For good specifications, you need industrial grade sensors.
Somewhere between home and industrial usage is the Panasonic SN-GCJA5 PM2.5 Laser Sensor for 25 dollars. Honeywell has the HPM Series for PM2.5 between 70 and 100 dollars.
i am actually looking for a cheap option, do you know a way to like manage what it measures? like how to code it too measure 1 pm ? i checked the arduino lib but it was only 2.5 and 10
That is not possible. They detect "dust".
Which Arduino library is that ?
If you mention something, please give links to it. I'm not an expert in dust sensors. I can read datasheets. That's all.
Arduino is for fast prototyping and learning about electronics and writing code.
There are many cheap sensors that are not accurate. Some make a library that presents a certain number, but it could be way off.
and do you know what connector do i have to use for it?? DSM501A i mean
There is something in the datasheet about the pin spacing, the sensor comes in 2mm pitch and 2.5mm pitch. The 2.5mm pitch is for a "S5B-EH" by JST.
I see now that it has normal output for particles larger than 1µm and another output that can be adjusted for particles larger than 2.5µm. But it is vague how that is done. The size of the particles is not measured.
That is completely different from the PM10 or PM2.5 standard.
PM10 is for particles of 10µm or less.
PM2.5 is for particles of 2.5µm or less.
https://en.wikipedia.org/wiki/Particulates
I think that if you use that library, then you get numbers that have nothing to do with PM10 or PM2.5.
Has someone checked the library with a calibrated sensor ? I don't think so.
So the lib is not real??
This is the open-source world. Everyone can make a library and write any code. Good or bad. The library shows numbers from the sensor, they increase if the dust increases. But those number are not PM10 or PM2.5.
You have to spend 100 dollars for a sensor.
There are libraries that calculate the lux from a LDR sensor, or a percentage of a certain gas with a MQ gas sensor, or the UV index from a sensor that has no UV sensor. The effort might be fun, but it is not serious.
The equipment to measure data in a laboratory on at an industrial plant is expensive for a reason.
And the final question, what is the difference between dust and pm2. 5??
I think that Wikipedia page explained it well.
Here is a more elaborated answer: https://www.epa.gov/pm-pollution/particulate-matter-pm-basics
i didnt get it, does the dust have anything to do with air quality??
"Air quality" and "Dust" are such vague words, they can be so many things.
The amount of particles in the air is one of the things for air quality.
The amount of certain gases is also important. A group of gases is called "VOC" gases. A simple sensor can detect those: https://www.sparkfun.com/products/18345
I just noticed that Adafruit has a PM2.5 particle sensor: https://www.adafruit.com/product/4632 With a tutorial and a blog. It is 45 dollars
The sensor itself is the cheapest in the range and made by a Chinese company Plantower: https://www.plantower.com/en/products_33/77.html
I used my 50 dollar on other sensors so I'm low on budget, I can spend 15 dollar and I'm looking for cheap sensors, I will use each sensor which is cheap, I will use the dust sensor if you recommend it (if it is required in air quality)
If you want to measure particles according to PM2.5, then the Adafruit sensor seems a good option.
Cheaper sensors measure "something", not PM2.5.