The organic compounds in the solid road dust were analyzed by pyrolysis-gas chromatography-mass spectrometry (py-GC-MS) using a G1942N model instrument (Agilent). The samples (1e5mg) were heated to 600C for 1min, and the evolved gas was analyzed by GC-MS with the oven temperature increasing at a rate of 10C min 1 from 50C to 320C. The compounds corresponding to prominent peaks were identified from among candidate compounds in the NIST 17 mass spectral library with a match quality above 90% by selecting those that matched with the highest probability. The compounds were grouped into 5 groupsdreference compounds, benzene derivatives, PAH derivatives, amines, and hydrocarbons excluding reference compounds. The reference compounds referred to saturated or unsaturated hydrocarbons with more than 10 carbon atoms, which were ubiquitous amongthedustsamples.Thesumofthepeakareas(%)wasdivided by the sum of the reference peak areas to calculate the relative abundance.The py-GC-MS spectra are shown in Fig. S2,and the list of compounds corresponding to each group is summarized in Table S4.