You can use the fontsetup package for easy configuration of fonts if you are willing to use XeLaTeX/LuaLaTeX. It supports two sans serif fonts Fira Sans and GFS Neohellenic, both with math support as of writing this answer.
\documentclass{article}
\usepackage[fira]{fontsetup}
%\usepackage[gfsneohellenic]{fontsetup}
\begin{document}
\section{Some section header.}
The quick brown fox jumps over the lazy dog.
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.
1234567890
\begin{align*}
\oint_{\gamma} \sum_{i=0}^n \int \bigcup \bigcap \\
\symup{\alpha \beta \gamma \delta \epsilon \zeta \eta \theta \iota \kappa \lambda \mu \nu \xi \omega \pi \rho \sigma \phi \psi \tau \omega}\\
\alpha \beta \gamma \delta \epsilon \zeta \eta \theta \iota \kappa \lambda \mu \nu \xi \omega \pi \rho \sigma \phi \psi \tau \omega \\
\partial \hbar \symbb{R, C, N, Z, Q}
\end{align*}
\end{document}
Fira: 
GFS Neohellenic: 
There exists Lato Math, but not on CTAN, probably because it is not polished enough. Generated .otf file from GitHub: LatoMath.otf.
\documentclass{article}
\usepackage{unicode-math}
\setmainfont{Lato}
\setmathfont{LatoMath.otf}
\begin{document}
\section{Some section header.}
The quick brown fox jumps over the lazy dog.
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.
1234567890
\begin{align*}
\oint_{\gamma} \sum_{i=0}^n \int \bigcup \bigcap \\
\symup{\alpha \beta \gamma \delta \epsilon \zeta \eta \theta \iota \kappa \lambda \mu \nu \xi \omega \pi \rho \sigma \phi \psi \tau \omega}\\
\alpha \beta \gamma \delta \epsilon \zeta \eta \theta \iota \kappa \lambda \mu \nu \xi \omega \pi \rho \sigma \phi \psi \tau \omega \\
\partial \hbar \symbb{R, C, N, Z, Q}
\end{align*}
\end{document}
You can use the notomath package for sans serif text and math (on pdfLaTeX, LuaLaTeX and XeLaTeX). Noto math has open type support planned for the future as well.
\documentclass{article}
\usepackage[sfdefault]{notomath}
\begin{document}
\section{Some section header.}
The quick brown fox jumps over the lazy dog.
THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.
1234567890
\begin{align*}
\oint_{\gamma} \sum_{i=0}^n \int \bigcup \bigcap \\
\alpha \beta \gamma \delta \epsilon \zeta \eta \theta \iota \kappa \lambda \mu \nu \xi \omega \pi \rho \sigma \phi \psi \tau \omega \\
\partial \hbar \mathbb{R, C, N, Z, Q}
\end{align*}
\end{document}
I don't know how to make the summation and the integral signs sans serif in Noto.
