Weather data such light intensity (lux), temperature and relative humidity are measured and recorded
by a DIY home unit. The data should be interpreted as one local condition. The tutorial and specifcation of this unit can be found here. You can make one of this with less than $20.
Wind data is retrieved and powered by Darksky API. It has a friendly API plus large sets of data.
Particulate concentration of PM2.5 measured by Nova Fitness SDS011. Healthy effect categories are based on the US EPA approach. While SDS011 is intented to measure the outdoor PM concentrations, the available space limits the representation of the PM concentration to a balcony (~10th floors) in the south of Hanoi.