This dataset contains direct infusion ultra-high resolution mass spectrometry measurements made at the Institute of Atmospheric Physics land station, Beijing (IAP-Beijing) site during the summer and winter APHH-Beijing campaign for the Atmospheric Pollution & Human Health in a Chinese Megacity (APHH) programme.

Daily quartz microfiber filters were collected with a Tisch high volume sampler. The extracted organic fraction of the collected PM2.5 particles was analysed using an LTQ Orbitrap Velos mass spectrometer with electrospray ionisation to obtain high resolution mass spectra which enable the assignment of molecular formulae to the detected masses.

For both seasons, 10 filters were analysed, containing the 5 filters with the highest and lowest mass loadings for each season. The files names are labeled according to the ID of the analysed filter. All dates and times are given in Beijing local time.