Pencemaran udara di Surabaya dapat disebabkan oleh gas emisi kendaraan bermotor berupa timbal (Pb). Ruellia Ungu (Ruellia Simplex C. Wright), Kamboja Pagoda (Plumeria pudica), Mondokaki (Tabernaemontana sp. var. variegate) adalah tanaman yang dapat dimanfaatkan sebagai penyerap timbal (Pb) di udara. Penelitian ini dilakukan untuk melihat adanya perbedaan kadar timbal pada tanaman Ruellia Ungu (Ruellia simplex C. Wright), Kamboja Pagoda (Plumeria pudica) dan Mondokaki (Tabernaemontana sp. Var. variegate) sebagai absorben timbal (Pb) di udara. Sampel daun diambil dari tiga lokasi yaitu : Jalan Diponegoro, Jalan Dr. H. Ir. Soekarno, dan Jalan Darmo di kota Surabaya. Sampel daun dari setiap tanaman diambil sebanyak 15 daun pada tiga titik di ketiga lokasi, sampel akan diuji kadar timbal (Pb) dengan metode pengabuan kering menggunakan alat Atomic Absorption Spectrophotometry (AAS) di Laboratorium Kimia Fisika Universitas Negeri Surabaya dan kadar klorofil daun dengan spektrofometer di Laboratorium Fisiologi Universitas Negeri Surabaya. Hasil penelitian yang telah dilakukan menunjukkan ketiga tanaman berpotensi mengabsorbsi timbal (Pb) di udara. Tanaman Ruellia Ungu memiliki kadar timbal daun tertinggi sebesar 0,75 mg/L, dibandingkan dengan Mondokaki dan Kamboja Pagoda. Tanaman Ruellia Ungu memiliki kadar klorofil tertinggi sebesar 19,72 mg/L dibandingkan dengan tanaman Mondokaki dan Kamboja Pagoda. Kadar timbal (Pb) berpengaruh terhadap luas permukaan daun Ruellia Ungu dan Mondokaki, sedangkan pada Kamboja Pagoda tidak berpengaruh.
Air pollution in Surabaya can be caused by motorized gas emissions in the form of lead (Pb). Ruellia Ungu (Ruellia Simplex C. Wright), Kamboja Pagoda (Plumeria pudica), Mondokaki (Tabernaemontana sp. var. Variegate) are plants that can be used as lead absorbers (Pb) in the air. This research was conducted to see the differences in lead levels in Purple Ruellia (Ruellia simplex C. Wright) plants, Cambodia Pagoda (Plumeria pudica) and Mondokaki (Tabernaemontana sp. Var. Variegate) as lead (Pb) absorbent in the air. Leaf samples were taken from three locations, namely: Jalan Diponegoro, Jalan Dr. H. Ir. Soekarno, and Jalan Darmo in the city of Surabaya. Leaf samples from each plant were taken as many as 15 leaves at three points in all three locations, the samples will be tested for lead levels (Pb) by dry ashing method using the Atomic Absorption Spectrophotometry (AAS) tool at the Physical Chemistry Laboratory of the State University of Surabaya and leaf chlorophyll levels with a spectropometer at Laboratory of Physiology, Surabaya State University. The results of research that have been carried out show that the three plants have the potential to absorb lead (Pb) in the air. The Ruellia Ungu plant has the highest leaf lead content of 0.75 mg / L, compared to Mondokaki and Cambodia Pagoda. The Ruellia Ungu plant has the highest chlorophyll content of 19.72 mg / L compared to the Mondokaki and Cambodia Pagoda plants. Lead content (Pb) affects the surface area of the leaves of Ruellia Ungu and Mondokaki, while in Cambodia the Pagoda has no effect.