Most indoor air pollution comes from sources inside the building.For example, adhesives, carpeting, upholstery, manufacturedwood products, copy machines, pesticides, and cleaning agentsmay emit volatile organic compounds (VOCs), includingformaldehyde. Environmental tobacco smoke contributes highlevels of VOCs, other toxic compounds, and respirableparticulate matter. Research shows that some VOCs can causechronic and acute health effects at high concentrations, and someare known carcinogens. Low to moderate levels of multiple VOCsmay also produce acute reactions. Combustion products such ascarbon monoxide, nitrogen dioxide, as well as respirable particles,can come from unvented kerosene and gas space heaters,woodstoves, fireplaces and gas stoves.We test for VOCs using the The Leadership in Energy andEnvironmental Design (LEED) Green Building Rating requirements.