The chemistry and emissions in indoor environments are important because it not only leads to indoor exposure, where human spend most of their time, but also contributes to outdoor air pollution. My research focuses on the reactive and partitioning processes in the atmosphere indoors and outdoors. One distinctive aspect of the indoor environment in comparison with outdoors is the large surface area that acts as both a sink and source of many gas-phase chemicals. Understanding the gas-surface interactions of indoor pollutants and reaction on surfaces is crucial for controlling indoor air quality and assessing its impact on human exposure. In this talk, I will present the results from the indoor air quality field campaign (House Observation of Microbial and Environmental Chemistry, HOMEChem) that revealed indoor surfaces as a dominant reservoir for many volatile species in a real-world experiment (e.g., ventilation, cleaning, cooking and air conditioner operation). I will also present results from lab and field studies of reactive chemistry of chlorine bleach cleaning emissions and its impact on indoor air quality and potential contribution to outdoors.