Are “DIY projects” valuable or publishable? I’m 17 and will be joining a UG physics program soon. I’ve done a lot of DIY projects over the years, ranging from electric arc speakers to air-quality and climate-control systems. Most of my projects involved Arduinos.

I’ve been thinking of conducting a five-year study on air quality and climate change using ten sensors (gas, dust, temperature, and humidity) and an Arduino. I will collect data for five years and then conclude my findings.


Can I publish such research anywhere?
Do these type of projects have any value or are they a waste of time?
You are asking whether you will be able to publish these data and use it as an edge. It all depends, as user2768's answer mentions, on the value that your work has. Specifically, you have to come up with a valid and important research question that you work will answer. For example,


the 5-year or even 10-year array of data for a number of sensors staying in your basement are useless
the online tool to monitor the dust quantity in the air in your neighbourhood is useful as a community project, is likely to be useful to your neighbours / town administration, and can be commercialized, but is unlikely to turn into a scientific article. I know of such a service in my city, and you can take some inspiration from it: Tion CityAir.
monitoring gas release and dust particle concentration next to a nearby industry plant or landfill is useful. It can become particularly useful if the administration of the plant / landfill is about to introduce some environmental safety measures and is seeking to quantify their efficiency. In this case, your research will be answering a well-defined question: "Are enter new safety measures here improving the air quality?". This is valuable and publishable. In this case, 5-year arrays of data are not required; most important is to monitor the air quality some time before the planned safety upgrade and some time after; I'd suggest at least three months before and after.


Bottom line: starting a 5-year data flow is easy. Coming up with a valid design of experiment is harder. 

Specific points to account when planning an air quality monitoring experiment: 


Are your gas sensors able to monitor the exact gases you are interested in? If you are targeting plant monitoring, ammonia and sulfur oxides come to mind, but there might be so much more. 
What particular dust particles you are able to quantify? For the environmental safety applications, PM2.5 particles are often the most risk-inducing.