This paper treats urban morphology as an environmental control surface. Its iconic operation is to test how changes in building height, density, street width, enclosure and openness alter the local distribution of noise and air pollution, rather than assuming that compactness or density carries a stable environmental value. The study uses a parametric Spacematrix-based method across thirty-one morphological models while controlling traffic mode, flows and speed, and translates exposure effects into disability-adjusted life years. The theoretical contribution is therefore a shift from generic sustainability claims to measurable morphological trade-offs: an opening that improves pollutant dispersion may simultaneously degrade acoustic protection, while densification can improve or worsen health outcomes depending on how traffic and built form interact. Methodologically, one variable is altered at a time to isolate causal influence. The broader intellectual bridge is to evidence-based design: urban form becomes a testable variable whose effects can be compared, quantified and used to formulate intervention priorities rather than treated as stylistic preference.